Annotation of OpenXM_contrib/gnuplot/docs/gnuplot.texi, Revision 1.1.1.2
1.1 maekawa 1: \input texinfo @c -*-texinfo-*-
2:
3: @c %**start of header
4: @setfilename gnuplot.info
5: @settitle Gnuplot: An Interactive Plotting Program
6: @setchapternewpage odd
7: @c %**end of header
8:
9: @c define the command and options indeces
10: @defindex cm
11: @defindex op
12: @defindex tm
13:
14: @direntry
15: * GNUPLOT: (gnuplot). An Interactive Plotting Program
16: @end direntry
17:
18: @ifnottex
19: @node Top, gnuplot, (dir), (dir)
20: @top Master Menu
21: @end ifnottex
22:
23: @example
24: GNUPLOT
25:
26: An Interactive Plotting Program
27: Thomas Williams & Colin Kelley
28: Version 3.7 organized by: David Denholm
29:
30: Copyright (C) 1986 - 1993, 1998 Thomas Williams, Colin Kelley
31:
32: Mailing list for comments: info-gnuplot@@dartmouth.edu
33: Mailing list for bug reports: bug-gnuplot@@dartmouth.edu
34:
35: This manual was prepared by Dick Crawford
36: 3 December 1998
37:
38:
39: Major contributors (alphabetic order):
40: @end example
41:
42: @c ^ <h2> An Interactive Plotting Program </h2><p>
43: @c ^ <h2> Thomas Williams & Colin Kelley</h2><p>
44: @c ^ <h2> Version 3.7 organized by: David Denholm </h2><p>
45: @c ^ <h2>Major contributors (alphabetic order):</h2>
46:
47: @itemize @bullet
48: @item
49: Hans-Bernhard Broeker
50: @item
51: John Campbell
52: @item
53: Robert Cunningham
54: @item
55: David Denholm
56: @item
57: Gershon Elber
58: @item
59: Roger Fearick
60: @item
61: Carsten Grammes
62: @item
63: Lucas Hart
64: @item
65: Lars Hecking
66: @item
67: Thomas Koenig
68: @item
69: David Kotz
70: @item
71: Ed Kubaitis
72: @item
73: Russell Lang
74: @item
75: Alexander Lehmann
76: @item
77: Alexander Mai
78: @item
79: Carsten Steger
80: @item
81: Tom Tkacik
82: @item
83: Jos Van der Woude
84: @item
85: James R. Van Zandt
86: @item
87: Alex Woo
88: @end itemize
89:
90: @c ^<h2> Copyright (C) 1986 - 1993, 1998 Thomas Williams, Colin Kelley<p>
91: @c ^ Mailing list for comments: info-gnuplot@@dartmouth.edu <p>
92: @c ^ Mailing list for bug reports: bug-gnuplot@@dartmouth.edu<p>
93: @c ^</h2><p>
94: @c ^<h3> This manual was prepared by Dick Crawford</h3><p>
95: @c ^<h3> 3 December 1998</h3><p>
96: @c ^<hr>
97:
98: @menu
99: * gnuplot::
100: * Commands::
101: * Graphical_User_Interfaces::
102: * Bugs::
103: * Concept_Index::
104: * Command_Index::
105: * Options_Index::
106: * Function_Index::
107: * Terminal_Index::
108: @end menu
109:
110: @node gnuplot, Commands, Top, Top
111: @chapter gnuplot
112:
113:
114: @menu
115: * Copyright::
116: * Introduction::
117: * Seeking-assistance::
118: * What's_New_in_version_3.7::
119: * Batch/Interactive_Operation::
120: * Command-line-editing::
121: * Comments::
122: * Coordinates::
123: * Environment::
124: * Expressions::
125: * Glossary::
126: * Plotting::
127: * Start-up::
128: * Substitution::
129: * Syntax::
130: * Time/Date_data::
131: @end menu
132:
133: @node Copyright, Introduction, gnuplot, gnuplot
134: @section Copyright
135:
136: @cindex copyright
137:
138: @cindex license
139:
140: @example
141: Copyright (C) 1986 - 1993, 1998 Thomas Williams, Colin Kelley
142:
143: @end example
144:
145: Permission to use, copy, and distribute this software and its
146: documentation for any purpose with or without fee is hereby granted,
147: provided that the above copyright notice appear in all copies and
148: that both that copyright notice and this permission notice appear
149: in supporting documentation.
150:
151: Permission to modify the software is granted, but not the right to
152: distribute the complete modified source code. Modifications are to
153: be distributed as patches to the released version. Permission to
154: distribute binaries produced by compiling modified sources is granted,
155: provided you
156: @example
157: 1. distribute the corresponding source modifications from the
158: released version in the form of a patch file along with the binaries,
159: 2. add special version identification to distinguish your version
160: in addition to the base release version number,
161: 3. provide your name and address as the primary contact for the
162: support of your modified version, and
163: 4. retain our contact information in regard to use of the base
164: software.
165: @end example
166:
167: Permission to distribute the released version of the source code along
168: with corresponding source modifications in the form of a patch file is
169: granted with same provisions 2 through 4 for binary distributions.
170:
171: This software is provided "as is" without express or implied warranty
172: to the extent permitted by applicable law.
173:
174:
175: @example
176: AUTHORS
177:
178: @end example
179:
180: @example
181: Original Software:
182: Thomas Williams, Colin Kelley.
183:
184: @end example
185:
186: @example
187: Gnuplot 2.0 additions:
188: Russell Lang, Dave Kotz, John Campbell.
189:
190: @end example
191:
192: @example
193: Gnuplot 3.0 additions:
194: Gershon Elber and many others.
195:
196: @end example
197:
198: @node Introduction, Seeking-assistance, Copyright, gnuplot
199: @section Introduction
200:
201: @cindex introduction
202:
203: @c ?
204: `gnuplot` is a command-driven interactive function and data plotting program.
205: It is case sensitive (commands and function names written in lowercase are
206: not the same as those written in CAPS). All command names may be abbreviated
207: as long as the abbreviation is not ambiguous. Any number of commands may
208: appear on a line (with the exception that @ref{load} or @ref{call} must be the final
209: command), separated by semicolons (;). Strings are indicated with quotes.
210: They may be either single or double quotation marks, e.g.,
211:
212: @example
213: load "filename"
214: cd 'dir'
215:
216: @end example
217:
218: although there are some subtle differences (see `syntax` for more details).
219:
220: Any command-line arguments are assumed to be names of files containing
221: `gnuplot` commands, with the exception of standard X11 arguments, which are
222: processed first. Each file is loaded with the @ref{load} command, in the order
223: specified. `gnuplot` exits after the last file is processed. When no load
224: files are named, `gnuplot` enters into an interactive mode. The special
225: filename "-" is used to denote standard input. See "help batch/interactive"
226: for more details.
227:
228: Many `gnuplot` commands have multiple options. These options must appear in
229: the proper order, although unwanted ones may be omitted in most cases. Thus
230: if the entire command is "command a b c", then "command a c" will probably
231: work, but "command c a" will fail.
232:
233: Commands may extend over several input lines by ending each line but the last
234: with a backslash (\). The backslash must be the _last_ character on each
235: line. The effect is as if the backslash and newline were not there. That
236: is, no white space is implied, nor is a comment terminated. Therefore,
237: commenting out a continued line comments out the entire command (see
238: `comment`). But note that if an error occurs somewhere on a multi-line
239: command, the parser may not be able to locate precisely where the error is
240: and in that case will not necessarily point to the correct line.
241:
242: In this document, curly braces (@{@}) denote optional arguments and a vertical
243: bar (|) separates mutually exclusive choices. `gnuplot` keywords or @ref{help}
244: topics are indicated by backquotes or `boldface` (where available). Angle
245: brackets (<>) are used to mark replaceable tokens. In many cases, a default
246: value of the token will be taken for optional arguments if the token is
247: omitted, but these cases are not always denoted with braces around the angle
248: brackets.
249:
250: For on-line help on any topic, type @ref{help} followed by the name of the topic
251: or just @ref{help} or `?` to get a menu of available topics.
252:
253: The new `gnuplot` user should begin by reading about `plotting` (if on-line,
254: type `help plotting`).
255: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/simple.html,Simple Plots Demo }
256:
257: @node Seeking-assistance, What's_New_in_version_3.7, Introduction, gnuplot
258: @section Seeking-assistance
259:
260: @cindex seeking-assistance
261:
262: There is a mailing list for `gnuplot` users. Note, however, that the
263: newsgroup
264: @example
265: comp.graphics.apps.gnuplot
266: @end example
267:
268: is identical to the mailing list (they both carry the same set of messages).
269: We prefer that you read the messages through the newsgroup rather than
270: subscribing to the mailing list. Administrative requests should be sent to
271: @example
272: majordomo@@dartmouth.edu
273: @end example
274:
275: Send a message with the body (not the subject) consisting of the single word
276: "help" (without the quotes) for more details.
277:
278: The address for mailing to list members is:
279: @example
280: info-gnuplot@@dartmouth.edu
281:
282: @end example
283:
284: Bug reports and code contributions should be mailed to:
285: @example
286: bug-gnuplot@@dartmouth.edu
287:
288: @end example
289:
290: The list of those interested in beta-test versions is:
291: @example
292: info-gnuplot-beta@@dartmouth.edu
293:
294: @end example
295:
296: There is also a World Wide Web page with up-to-date information, including
297: known bugs:
298: @uref{http://www.cs.dartmouth.edu/gnuplot_info.html,http://www.cs.dartmouth.edu/gnuplot_info.html
299: }
300:
301: Before seeking help, please check the
302: @uref{http://www.ucc.ie/gnuplot/gnuplot-faq.html,FAQ (Frequently Asked Questions) list.
303: }
304: If you do not have a copy of the FAQ, you may request a copy by email from
305: the Majordomo address above, ftp a copy from
306: @example
307: ftp://ftp.ucc.ie/pub/gnuplot/faq,
308: ftp://ftp.gnuplot.vt.edu/pub/gnuplot/faq,
309: @end example
310:
311: or see the WWW `gnuplot` page.
312:
313: When posting a question, please include full details of the version of
314: `gnuplot`, the machine, and operating system you are using. A _small_ script
315: demonstrating the problem may be useful. Function plots are preferable to
316: datafile plots. If email-ing to info-gnuplot, please state whether or not
317: you are subscribed to the list, so that users who use news will know to email
318: a reply to you. There is a form for such postings on the WWW site.
319:
320: @node What's_New_in_version_3.7, Batch/Interactive_Operation, Seeking-assistance, gnuplot
321: @section What's New in version 3.7
322:
323: @cindex new-features
324:
325: Gnuplot version 3.7 contains many new features. This section gives a partial
326: list and links to the new items in no particular order.
327:
328: 1. `fit f(x) 'file' via` uses the Marquardt-Levenberg method to fit data.
329: (This is only slightly different from the `gnufit` patch available for 3.5.)
330:
331: 2. Greatly expanded @ref{using} command. See @ref{using}.
332:
333: 3. @ref{timefmt} allows for the use of dates as input and output for time
334: series plots. See `Time/Date data` and
335: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/timedat.html,timedat.dem.
336: }
337:
338: 4. Multiline labels and font selection in some drivers.
339:
340: 5. Minor (unlabeled) tics. See @ref{mxtics}.
341:
342: 6. @ref{key} options for moving the key box in the page (and even outside of the
343: plot), putting a title on it and a box around it, and more. See @ref{key}.
344:
345: 7. Multiplots on a single logical page with @ref{multiplot}.
346:
347: 8. Enhanced `postscript` driver with super/subscripts and font changes.
348: (This was a separate driver (`enhpost`) that was available as a patch for
349: 3.5.)
350:
351: 9. Second axes: use the top and right axes independently of the bottom and
352: left, both for plotting and labels. See @ref{plot}.
353:
354: 10. Special datafile names `'-'` and `""`. See @ref{special-filenames}.
355:
356: 11. Additional coordinate systems for labels and arrows. See `coordinates`.
357:
358: 12. @ref{size} can try to plot with a specified aspect ratio.
359:
360: 13. @ref{missing} now treats missing data correctly.
361:
362: 14. The @ref{call} command: @ref{load} with arguments.
363:
364: 15. More flexible `range` commands with `reverse` and `writeback` keywords.
365:
366: 16. @ref{encoding} for multi-lingual encoding.
367:
368: 17. New `x11` driver with persistent and multiple windows.
369:
370: 18. New plotting styles: @ref{xerrorbars}, @ref{histeps}, @ref{financebars} and more.
371: See @ref{style}.
372:
373: 19. New tic label formats, including `"%l %L"` which uses the mantissa and
374: exponents to a given base for labels. See `set format`.
375:
376: 20. New drivers, including `cgm` for inclusion into MS-Office applications
377: and `gif` for serving plots to the WEB.
378:
379: 21. Smoothing and spline-fitting options for @ref{plot}. See @ref{smooth}.
380:
381: 22. @ref{margin} and @ref{origin} give much better control over where a
382: graph appears on the page.
383:
384: 23. @ref{border} now controls each border individually.
385:
386: 24. The new commands @ref{if} and @ref{reread} allow command loops.
387:
388: 25. Point styles and sizes, line types and widths can be specified on the
389: @ref{plot} command. Line types and widths can also be specified for grids,
390: borders, tics and arrows. See @ref{with}. Furthermore these types may be
391: combined and stored for further use. See @ref{linestyle}.
392:
393: 26. Text (labels, tic labels, and the time stamp) can be written vertically
394: by those terminals capable of doing so.
395:
396: @node Batch/Interactive_Operation, Command-line-editing, What's_New_in_version_3.7, gnuplot
397: @section Batch/Interactive Operation
398:
399: @cindex batch/interactive
400:
401: `gnuplot` may be executed in either batch or interactive modes, and the two
402: may even be mixed together on many systems.
403:
404: Any command-line arguments are assumed to be names of files containing
405: `gnuplot` commands (with the exception of standard X11 arguments, which are
406: processed first). Each file is loaded with the @ref{load} command, in the order
407: specified. `gnuplot` exits after the last file is processed. When no load
408: files are named, `gnuplot` enters into an interactive mode. The special
409: filename "-" is used to denote standard input.
410:
411: Both the @ref{exit} and @ref{quit} commands terminate the current command file and
412: @ref{load} the next one, until all have been processed.
413:
414: Examples:
415:
416: To launch an interactive session:
417: @example
418: gnuplot
419:
420: @end example
421:
422: To launch a batch session using two command files "input1" and "input2":
423: @example
424: gnuplot input1 input2
425:
426: @end example
427:
428: To launch an interactive session after an initialization file "header" and
429: followed by another command file "trailer":
430: @example
431: gnuplot header - trailer
432:
433: @end example
434:
435: @node Command-line-editing, Comments, Batch/Interactive_Operation, gnuplot
436: @section Command-line-editing
437:
438: @cindex line-editing
439:
440: @cindex editing
441:
442: @cindex history
443:
444: @cindex command-line-editing
445:
446: Command-line editing is supported by the Unix, Atari, VMS, MS-DOS and OS/2
447: versions of `gnuplot`. Also, a history mechanism allows previous commands to
448: be edited and re-executed. After the command line has been edited, a newline
449: or carriage return will enter the entire line without regard to where the
450: cursor is positioned.
451:
452: (The readline function in `gnuplot` is not the same as the readline used in
453: GNU Bash and GNU Emacs. If the GNU version is desired, it may be selected
454: instead of the `gnuplot` version at compile time.)
455:
456:
457: The editing commands are as follows:
458:
459:
460: @example
461: `Line-editing`:
462:
463: @end example
464:
465: @example
466: ^B moves back a single character.
467: ^F moves forward a single character.
468: ^A moves to the beginning of the line.
469: ^E moves to the end of the line.
470: ^H and DEL delete the previous character.
471: ^D deletes the current character.
472: ^K deletes from current position to the end of line.
473: ^L,^R redraws line in case it gets trashed.
474: ^U deletes the entire line.
475: ^W deletes the last word.
476:
477: @end example
478:
479: @example
480: `History`:
481:
482: @end example
483:
484: @example
485: ^P moves back through history.
486: ^N moves forward through history.
487:
488: @end example
489:
490:
491: On the IBM PC, the use of a TSR program such as DOSEDIT or CED may be desired
492: for line editing. The default makefile assumes that this is the case; by
493: default `gnuplot` will be compiled with no line-editing capability. If you
494: want to use `gnuplot`'s line editing, set READLINE in the makefile and add
495: readline.obj to the link file. The following arrow keys may be used on the
496: IBM PC and Atari versions if readline is used:
497:
498:
499: @example
500: Left Arrow - same as ^B.
501: Right Arrow - same as ^F.
502: Ctrl Left Arrow - same as ^A.
503: Ctrl Right Arrow - same as ^E.
504: Up Arrow - same as ^P.
505: Down Arrow - same as ^N.
506:
507: @end example
508:
509:
510: The Atari version of readline defines some additional key aliases:
511:
512:
513: @example
514: Undo - same as ^L.
515: Home - same as ^A.
516: Ctrl Home - same as ^E.
517: Esc - same as ^U.
518: Help - @ref{help} plus return.
519: Ctrl Help - `help `.
520:
521: @end example
522:
523:
524: @node Comments, Coordinates, Command-line-editing, gnuplot
525: @section Comments
526:
527: @cindex comments
528:
529: Comments are supported as follows: a `#` may appear in most places in a line
530: and `gnuplot` will ignore the rest of the line. It will not have this effect
531: inside quotes, inside numbers (including complex numbers), inside command
532: substitutions, etc. In short, it works anywhere it makes sense to work.
533:
534: @node Coordinates, Environment, Comments, gnuplot
535: @section Coordinates
536:
537: @cindex coordinates
538:
539: The commands @ref{arrow}, @ref{key}, and @ref{label} allow you to draw
540: something at an arbitrary position on the graph. This position is specified
541: by the syntax:
542:
543: @example
544: @{<system>@} <x>, @{<system>@} <y> @{,@{<system>@} <z>@}
545:
546: @end example
547:
548: Each <system> can either be `first`, `second`, `graph` or `screen`.
549:
550: `first` places the x, y, or z coordinate in the system defined by the left
551: and bottom axes; `second` places it in the system defined by the second axes
552: (top and right); `graph` specifies the area within the axes---0,0 is bottom
553: left and 1,1 is top right (for splot, 0,0,0 is bottom left of plotting area;
554: use negative z to get to the base---see @ref{ticslevel}); and `screen`
555: specifies the screen area (the entire area---not just the portion selected by
556: @ref{size}), with 0,0 at bottom left and 1,1 at top right.
557:
558: If the coordinate system for x is not specified, `first` is used. If the
559: system for y is not specified, the one used for x is adopted.
560:
561: If one (or more) axis is timeseries, the appropriate coordinate should
562: be given as a quoted time string according to the @ref{timefmt} format string.
563: See @ref{xdata} and @ref{timefmt}. `gnuplot` will also accept an integer
564: expression, which will be interpreted as seconds from 1 January 2000.
565:
566: @node Environment, Expressions, Coordinates, gnuplot
567: @section Environment
568:
569: @cindex environment
570:
571: A number of shell environment variables are understood by `gnuplot`. None of
572: these are required, but may be useful.
573:
574: If GNUTERM is defined, it is used as the name of the terminal type to be
575: used. This overrides any terminal type sensed by `gnuplot` on start-up, but
576: is itself overridden by the .gnuplot (or equivalent) start-up file (see
577: `start-up`) and, of course, by later explicit changes.
578:
579: On Unix, AmigaOS, AtariTOS, MS-DOS and OS/2, GNUHELP may be defined to be the
580: pathname of the HELP file (gnuplot.gih).
581:
582: On VMS, the logical name GNUPLOT$HELP should be defined as the name of the
583: help library for `gnuplot`. The `gnuplot` help can be put inside any system
584: help library, allowing access to help from both within and outside `gnuplot`
585: if desired.
586:
587: On Unix, HOME is used as the name of a directory to search for a .gnuplot
588: file if none is found in the current directory. On AmigaOS, AtariTOS,
589: MS-DOS and OS/2, gnuplot is used. On VMS, SYS$LOGIN: is used. See `help
590: start-up`.
591:
592: On Unix, PAGER is used as an output filter for help messages.
593:
594: On Unix, AtariTOS and AmigaOS, SHELL is used for the @ref{shell} command. On
595: MS-DOS and OS/2, COMSPEC is used for the @ref{shell} command.
596:
597: On MS-DOS, if the BGI or Watcom interface is used, PCTRM is used to tell
598: the maximum resolution supported by your monitor by setting it to
599: S<max. horizontal resolution>. E.g. if your monitor's maximum resolution is
600: 800x600, then use:
601: @example
602: set PCTRM=S800
603: @end example
604:
605: If PCTRM is not set, standard VGA is used.
606:
607: FIT_SCRIPT may be used to specify a `gnuplot` command to be executed when a
608: fit is interrupted---see `fit`. FIT_LOG specifies the filename of the
609: logfile maintained by fit.
610:
611: @node Expressions, Glossary, Environment, gnuplot
612: @section Expressions
613:
614: @cindex expressions
615:
616: In general, any mathematical expression accepted by C, FORTRAN, Pascal, or
617: BASIC is valid. The precedence of these operators is determined by the
618: specifications of the C programming language. White space (spaces and tabs)
619: is ignored inside expressions.
620:
621: Complex constants are expressed as @{<real>,<imag>@}, where <real> and <imag>
622: must be numerical constants. For example, @{3,2@} represents 3 + 2i; @{0,1@}
623: represents 'i' itself. The curly braces are explicitly required here.
624:
625: Note that gnuplot uses both "real" and "integer" arithmetic, like FORTRAN and
626: C. Integers are entered as "1", "-10", etc; reals as "1.0", "-10.0", "1e1",
627: 3.5e-1, etc. The most important difference between the two forms is in
628: division: division of integers truncates: 5/2 = 2; division of reals does
629: not: 5.0/2.0 = 2.5. In mixed expressions, integers are "promoted" to reals
630: before evaluation: 5/2e0 = 2.5. The result of division of a negative integer
631: by a positive one may vary among compilers. Try a test like "print -5/2" to
632: determine if your system chooses -2 or -3 as the answer.
633:
634: The integer expression "1/0" may be used to generate an "undefined" flag,
635: which causes a point to ignored; the `ternary` operator gives an example.
636:
637: The real and imaginary parts of complex expressions are always real, whatever
638: the form in which they are entered: in @{3,2@} the "3" and "2" are reals, not
639: integers.
640:
641: @menu
642: * Functions::
643: * Operators::
644: * User-defined::
645: @end menu
646:
647: @node Functions, Operators, Expressions, Expressions
648: @subsection Functions
649:
650: @c ?expressions functions
651: @cindex functions
652: @opindex functions
653:
654:
655: The functions in `gnuplot` are the same as the corresponding functions in
656: the Unix math library, except that all functions accept integer, real, and
657: complex arguments, unless otherwise noted.
658:
659: For those functions that accept or return angles that may be given in either
660: degrees or radians (sin(x), cos(x), tan(x), asin(x), acos(x), atan(x),
661: atan2(x) and arg(z)), the unit may be selected by @ref{angles}, which
662: defaults to radians.
663:
664:
665:
666: @menu
667: * abs::
668: * acos::
669: * acosh::
670: * arg::
671: * asin::
672: * asinh::
673: * atan::
674: * atan2::
675: * atanh::
676: * besj0::
677: * besj1::
678: * besy0::
679: * besy1::
680: * ceil::
681: * cos::
682: * cosh::
683: * erf::
684: * erfc::
685: * exp::
686: * floor::
687: * gamma::
688: * ibeta::
689: * inverf::
690: * igamma::
691: * imag::
692: * invnorm::
693: * int::
694: * lgamma::
695: * log::
696: * log10::
697: * norm::
698: * rand::
699: * real::
700: * sgn::
701: * sin::
702: * sinh::
703: * sqrt::
704: * tan::
705: * tanh::
706: * column::
707: * tm_hour::
708: * tm_mday::
709: * tm_min::
710: * tm_mon::
711: * tm_sec::
712: * tm_wday::
713: * tm_yday::
714: * tm_year::
715: * valid::
716: @end menu
717:
718: @node abs, acos, Functions, Functions
719: @subsubsection abs
720:
721: @c ?expressions functions abs
722: @c ?functions abs
723: @cindex abs
724: @findex abs
725:
726:
727: The `abs(x)` function returns the absolute value of its argument. The
728: returned value is of the same type as the argument.
729:
730: For complex arguments, abs(x) is defined as the length of x in the complex
731: plane [i.e., sqrt(real(x)**2 + imag(x)**2) ].
732:
733: @node acos, acosh, abs, Functions
734: @subsubsection acos
735:
736: @c ?expressions functions acos
737: @c ?functions acos
738: @cindex acos
739: @findex acos
740:
741:
742: The `acos(x)` function returns the arc cosine (inverse cosine) of its
743: argument. `acos` returns its argument in radians or degrees, as selected by
744: @ref{angles}.
745:
746: @node acosh, arg, acos, Functions
747: @subsubsection acosh
748:
749: @c ?expressions functions acosh
750: @c ?functions acosh
751: @cindex acosh
752: @findex acosh
753:
754:
755: The `acosh(x)` function returns the inverse hyperbolic cosine of its argument
756: in radians.
757:
758: @node arg, asin, acosh, Functions
759: @subsubsection arg
760:
761: @c ?expressions functions arg
762: @c ?functions arg
763: @cindex arg
764: @findex arg
765:
766:
767: The `arg(x)` function returns the phase of a complex number in radians or
768: degrees, as selected by @ref{angles}.
769:
770: @node asin, asinh, arg, Functions
771: @subsubsection asin
772:
773: @c ?expressions functions asin
774: @c ?functions asin
775: @cindex asin
776: @findex asin
777:
778:
779: The `asin(x)` function returns the arc sin (inverse sin) of its argument.
780: `asin` returns its argument in radians or degrees, as selected by @ref{angles}.
781:
782: @node asinh, atan, asin, Functions
783: @subsubsection asinh
784:
785: @c ?expressions functions asinh
786: @c ?functions asinh
787: @cindex asinh
788: @findex asinh
789:
790:
791: The `asinh(x)` function returns the inverse hyperbolic sin of its argument in
792: radians.
793:
794: @node atan, atan2, asinh, Functions
795: @subsubsection atan
796:
797: @c ?expressions functions atan
798: @c ?functions atan
799: @cindex atan
800: @findex atan
801:
802:
803: The `atan(x)` function returns the arc tangent (inverse tangent) of its
804: argument. `atan` returns its argument in radians or degrees, as selected by
805: @ref{angles}.
806:
807: @node atan2, atanh, atan, Functions
808: @subsubsection atan2
809:
810: @c ?expressions functions atan2
811: @c ?functions atan2
812: @cindex atan2
813: @findex atan2
814:
815:
816: The `atan2(y,x)` function returns the arc tangent (inverse tangent) of the
817: ratio of the real parts of its arguments. @ref{atan2} returns its argument in
818: radians or degrees, as selected by @ref{angles}, in the correct quadrant.
819:
820: @node atanh, besj0, atan2, Functions
821: @subsubsection atanh
822:
823: @c ?expressions functions atanh
824: @c ?functions atanh
825: @cindex atanh
826: @findex atanh
827:
828:
829: The `atanh(x)` function returns the inverse hyperbolic tangent of its
830: argument in radians.
831:
832: @node besj0, besj1, atanh, Functions
833: @subsubsection besj0
834:
835: @c ?expressions functions besj0
836: @c ?functions besj0
837: @cindex besj0
838: @findex besj0
839:
840:
841: The `besj0(x)` function returns the j0th Bessel function of its argument.
842: @ref{besj0} expects its argument to be in radians.
843:
844: @node besj1, besy0, besj0, Functions
845: @subsubsection besj1
846:
847: @c ?expressions functions besj1
848: @c ?functions besj1
849: @cindex besj1
850: @findex besj1
851:
852:
853: The `besj1(x)` function returns the j1st Bessel function of its argument.
854: @ref{besj1} expects its argument to be in radians.
855:
856: @node besy0, besy1, besj1, Functions
857: @subsubsection besy0
858:
859: @c ?expressions functions besy0
860: @c ?functions besy0
861: @cindex besy0
862: @findex besy0
863:
864:
865: The @ref{besy0} function returns the y0th Bessel function of its argument.
866: @ref{besy0} expects its argument to be in radians.
867:
868: @node besy1, ceil, besy0, Functions
869: @subsubsection besy1
870:
871: @c ?expressions functions besy1
872: @c ?functions besy1
873: @cindex besy1
874: @findex besy1
875:
876:
877: The `besy1(x)` function returns the y1st Bessel function of its argument.
878: @ref{besy1} expects its argument to be in radians.
879:
880: @node ceil, cos, besy1, Functions
881: @subsubsection ceil
882:
883: @c ?expressions functions ceil
884: @c ?functions ceil
885: @cindex ceil
886: @findex ceil
887:
888:
889: The `ceil(x)` function returns the smallest integer that is not less than its
890: argument. For complex numbers, @ref{ceil} returns the smallest integer not less
891: than the real part of its argument.
892:
893: @node cos, cosh, ceil, Functions
894: @subsubsection cos
895:
896: @c ?expressions functions cos
897: @c ?functions cos
898: @cindex cos
899: @findex cos
900:
901:
902: The `cos(x)` function returns the cosine of its argument. `cos` accepts its
903: argument in radians or degrees, as selected by @ref{angles}.
904:
905: @node cosh, erf, cos, Functions
906: @subsubsection cosh
907:
908: @c ?expressions functions cosh
909: @c ?functions cosh
910: @cindex cosh
911: @findex cosh
912:
913:
914: The `cosh(x)` function returns the hyperbolic cosine of its argument. @ref{cosh}
915: expects its argument to be in radians.
916:
917: @node erf, erfc, cosh, Functions
918: @subsubsection erf
919:
920: @c ?expressions functions erf
921: @c ?functions erf
922: @cindex erf
923: @findex erf
924:
925:
926: The `erf(x)` function returns the error function of the real part of its
927: argument. If the argument is a complex value, the imaginary component is
928: ignored.
929:
930: @node erfc, exp, erf, Functions
931: @subsubsection erfc
932:
933: @c ?expressions functions erfc
934: @c ?functions erfc
935: @cindex erfc
936: @findex erfc
937:
938:
939: The `erfc(x)` function returns 1.0 - the error function of the real part of
940: its argument. If the argument is a complex value, the imaginary component is
941: ignored.
942:
943: @node exp, floor, erfc, Functions
944: @subsubsection exp
945:
946: @c ?expressions functions exp
947: @c ?functions exp
948: @cindex exp
949: @findex exp
950:
951:
952: The `exp(x)` function returns the exponential function of its argument (`e`
953: raised to the power of its argument). On some implementations (notably
954: suns), exp(-x) returns undefined for very large x. A user-defined function
955: like safe(x) = x<-100 ? 0 : exp(x) might prove useful in these cases.
956:
957: @node floor, gamma, exp, Functions
958: @subsubsection floor
959:
960: @c ?expressions functions floor
961: @c ?functions floor
962: @cindex floor
963: @findex floor
964:
965:
966: The `floor(x)` function returns the largest integer not greater than its
967: argument. For complex numbers, @ref{floor} returns the largest integer not
968: greater than the real part of its argument.
969:
970: @node gamma, ibeta, floor, Functions
971: @subsubsection gamma
972:
973: @c ?expressions functions gamma
974: @c ?functions gamma
975: @cindex gamma
976: @findex gamma
977:
978:
979: The `gamma(x)` function returns the gamma function of the real part of its
980: argument. For integer n, gamma(n+1) = n!. If the argument is a complex
981: value, the imaginary component is ignored.
982:
983: @node ibeta, inverf, gamma, Functions
984: @subsubsection ibeta
985:
986: @c ?expressions functions ibeta
987: @c ?functions ibeta
988: @cindex ibeta
989: @findex ibeta
990:
991:
992: The `ibeta(p,q,x)` function returns the incomplete beta function of the real
993: parts of its arguments. p, q > 0 and x in [0:1]. If the arguments are
994: complex, the imaginary components are ignored.
995:
996: @node inverf, igamma, ibeta, Functions
997: @subsubsection inverf
998:
999: @c ?expressions functions inverf
1000: @c ?functions inverf
1001: @cindex inverf
1002: @findex inverf
1003:
1004:
1005: The `inverf(x)` function returns the inverse error function of the real part
1006: of its argument.
1007:
1008: @node igamma, imag, inverf, Functions
1009: @subsubsection igamma
1010:
1011: @c ?expressions functions igamma
1012: @c ?functions igamma
1013: @cindex igamma
1014: @findex igamma
1015:
1016:
1017: The `igamma(a,x)` function returns the incomplete gamma function of the real
1018: parts of its arguments. a > 0 and x >= 0. If the arguments are complex,
1019: the imaginary components are ignored.
1020:
1021: @node imag, invnorm, igamma, Functions
1022: @subsubsection imag
1023:
1024: @c ?expressions functions imag
1025: @c ?functions imag
1026: @cindex imag
1027: @findex imag
1028:
1029:
1030: The `imag(x)` function returns the imaginary part of its argument as a real
1031: number.
1032:
1033: @node invnorm, int, imag, Functions
1034: @subsubsection invnorm
1035:
1036: @c ?expressions functions invnorm
1037: @c ?functions invnorm
1038: @cindex invnorm
1039: @findex invnorm
1040:
1041:
1042: The `invnorm(x)` function returns the inverse normal distribution function of
1043: the real part of its argument.
1044:
1045: @node int, lgamma, invnorm, Functions
1046: @subsubsection int
1047:
1048: @c ?expressions functions int
1049: @c ?functions int
1050: @cindex int
1051: @findex int
1052:
1053:
1054: The `int(x)` function returns the integer part of its argument, truncated
1055: toward zero.
1056:
1057: @node lgamma, log, int, Functions
1058: @subsubsection lgamma
1059:
1060: @c ?expressions functions lgamma
1061: @c ?functions lgamma
1062: @cindex lgamma
1063: @findex lgamma
1064:
1065:
1066: The `lgamma(x)` function returns the natural logarithm of the gamma function
1067: of the real part of its argument. If the argument is a complex value, the
1068: imaginary component is ignored.
1069:
1070: @node log, log10, lgamma, Functions
1071: @subsubsection log
1072:
1073: @c ?expressions functions log
1074: @c ?functions log
1075: @cindex log
1076: @findex log
1077:
1078:
1079: The `log(x)` function returns the natural logarithm (base `e`) of its
1080: argument.
1081:
1082: @node log10, norm, log, Functions
1083: @subsubsection log10
1084:
1085: @c ?expressions functions log10
1086: @c ?functions log10
1087: @cindex log10
1088: @findex log10
1089:
1090:
1091: The `log10(x)` function returns the logarithm (base 10) of its argument.
1092:
1093: @node norm, rand, log10, Functions
1094: @subsubsection norm
1095:
1096: @c ?expressions functions norm
1097: @c ?functions norm
1098: @cindex norm
1099: @findex norm
1100:
1101:
1102: The `norm(x)` function returns the normal distribution function (or Gaussian)
1103: of the real part of its argument.
1104:
1105: @node rand, real, norm, Functions
1106: @subsubsection rand
1107:
1108: @c ?expressions functions rand
1109: @c ?functions rand
1110: @cindex rand
1111: @findex rand
1112:
1113:
1114: The `rand(x)` function returns a pseudo random number in the interval [0:1]
1115: using the real part of its argument as a seed. If seed < 0, the sequence
1116: is (re)initialized. If the argument is a complex value, the imaginary
1117: component is ignored.
1118:
1119: @node real, sgn, rand, Functions
1120: @subsubsection real
1121:
1122: @c ?expressions functions real
1123: @c ?functions real
1124: @cindex real
1125: @findex real
1126:
1127:
1128: The `real(x)` function returns the real part of its argument.
1129:
1130: @node sgn, sin, real, Functions
1131: @subsubsection sgn
1132:
1133: @c ?expressions functions sgn
1134: @c ?functions sgn
1135: @cindex sgn
1136: @findex sgn
1137:
1138:
1139: The `sgn(x)` function returns 1 if its argument is positive, -1 if its
1140: argument is negative, and 0 if its argument is 0. If the argument is a
1141: complex value, the imaginary component is ignored.
1142:
1143: @node sin, sinh, sgn, Functions
1144: @subsubsection sin
1145:
1146: @c ?expressions functions sin
1147: @c ?functions sin
1148: @cindex sin
1149: @findex sin
1150:
1151:
1152: The `sin(x)` function returns the sine of its argument. `sin` expects its
1153: argument to be in radians or degrees, as selected by @ref{angles}.
1154:
1155: @node sinh, sqrt, sin, Functions
1156: @subsubsection sinh
1157:
1158: @c ?expressions functions sinh
1159: @c ?functions sinh
1160: @cindex sinh
1161: @findex sinh
1162:
1163:
1164: The `sinh(x)` function returns the hyperbolic sine of its argument. @ref{sinh}
1165: expects its argument to be in radians.
1166:
1167: @node sqrt, tan, sinh, Functions
1168: @subsubsection sqrt
1169:
1170: @c ?expressions functions sqrt
1171: @c ?functions sqrt
1172: @cindex sqrt
1173: @findex sqrt
1174:
1175:
1176: The `sqrt(x)` function returns the square root of its argument.
1177:
1178: @node tan, tanh, sqrt, Functions
1179: @subsubsection tan
1180:
1181: @c ?expressions functions tan
1182: @c ?functions tan
1183: @cindex tan
1184: @findex tan
1185:
1186:
1187: The `tan(x)` function returns the tangent of its argument. `tan` expects
1188: its argument to be in radians or degrees, as selected by @ref{angles}.
1189:
1190: @node tanh, column, tan, Functions
1191: @subsubsection tanh
1192:
1193: @c ?expressions functions tanh
1194: @c ?functions tanh
1195: @cindex tanh
1196: @findex tanh
1197:
1198:
1199: The `tanh(x)` function returns the hyperbolic tangent of its argument. @ref{tanh}
1200: expects its argument to be in radians.
1201:
1202:
1203: A few additional functions are also available.
1204:
1205:
1206:
1207: @node column, tm_hour, tanh, Functions
1208: @subsubsection column
1209:
1210: @c ?expressions functions column
1211: @c ?functions column
1212: @cindex column
1213: @findex column
1214:
1215:
1216: `column(x)` may be used only in expressions as part of @ref{using} manipulations
1217: to fits or datafile plots. See @ref{using}.
1218:
1219: @node tm_hour, tm_mday, column, Functions
1220: @subsubsection tm_hour
1221:
1222: @c ?expressions tm_hour
1223: @findex tm_hour
1224: @c ?functions tm_hour
1225: The @ref{tm_hour} function interprets its argument as a time, in seconds from
1226: 1 Jan 2000. It returns the hour (an integer in the range 0--23) as a real.
1227:
1228: @node tm_mday, tm_min, tm_hour, Functions
1229: @subsubsection tm_mday
1230:
1231: @c ?expressions tm_mday
1232: @findex tm_mday
1233: @c ?functions tm_mday
1234: The @ref{tm_mday} function interprets its argument as a time, in seconds from
1235: 1 Jan 2000. It returns the day of the month (an integer in the range 1--31)
1236: as a real.
1237:
1238: @node tm_min, tm_mon, tm_mday, Functions
1239: @subsubsection tm_min
1240:
1241: @c ?expressions tm_min
1242: @findex tm_min
1243: @c ?functions tm_min
1244: The @ref{tm_min} function interprets its argument as a time, in seconds from
1245: 1 Jan 2000. It returns the minute (an integer in the range 0--59) as a real.
1246:
1247: @node tm_mon, tm_sec, tm_min, Functions
1248: @subsubsection tm_mon
1249:
1250: @c ?expressions tm_mon
1251: @findex tm_mon
1252: @c ?functions tm_mon
1253: The @ref{tm_mon} function interprets its argument as a time, in seconds from
1254: 1 Jan 2000. It returns the month (an integer in the range 1--12) as a real.
1255:
1256: @node tm_sec, tm_wday, tm_mon, Functions
1257: @subsubsection tm_sec
1258:
1259: @c ?expressions tm_sec
1260: @findex tm_sec
1261: @c ?functions tm_sec
1262: The @ref{tm_sec} function interprets its argument as a time, in seconds from
1263: 1 Jan 2000. It returns the second (an integer in the range 0--59) as a real.
1264:
1265: @node tm_wday, tm_yday, tm_sec, Functions
1266: @subsubsection tm_wday
1267:
1268: @c ?expressions tm_wday
1269: @findex tm_wday
1270: @c ?functions tm_wday
1271: The @ref{tm_wday} function interprets its argument as a time, in seconds from
1272: 1 Jan 2000. It returns the day of the week (an integer in the range 1--7) as
1273: a real.
1274:
1275: @node tm_yday, tm_year, tm_wday, Functions
1276: @subsubsection tm_yday
1277:
1278: @c ?expressions tm_yday
1279: @findex tm_yday
1280: @c ?functions tm_yday
1281: The @ref{tm_yday} function interprets its argument as a time, in seconds from
1282: 1 Jan 2000. It returns the day of the year (an integer in the range 1--366)
1283: as a real.
1284:
1285: @node tm_year, valid, tm_yday, Functions
1286: @subsubsection tm_year
1287:
1288: @c ?expressions tm_year
1289: @findex tm_year
1290: @c ?functions tm_year
1291: The @ref{tm_year} function interprets its argument as a time, in seconds from
1292: 1 Jan 2000. It returns the year (an integer) as a real.
1293:
1294: @node valid, , tm_year, Functions
1295: @subsubsection valid
1296:
1297: @c ?expressions functions valid
1298: @c ?functions valid
1299: @cindex valid
1300: @findex valid
1301:
1302:
1303: `valid(x)` may be used only in expressions as part of @ref{using} manipulations
1304: to fits or datafile plots. See @ref{using}.
1305:
1306: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/airfoil.html,Use of functions and complex variables for airfoils }
1307:
1308: @node Operators, User-defined, Functions, Expressions
1309: @subsection Operators
1310:
1311: @c ?expressions operators
1312: @cindex operators
1313:
1314: The operators in `gnuplot` are the same as the corresponding operators in the
1315: C programming language, except that all operators accept integer, real, and
1316: complex arguments, unless otherwise noted. The ** operator (exponentiation)
1317: is supported, as in FORTRAN.
1318:
1319: Parentheses may be used to change order of evaluation.
1320:
1321: @menu
1322: * Unary::
1323: * Binary::
1324: * Ternary::
1325: @end menu
1326:
1327: @node Unary, Binary, Operators, Operators
1328: @subsubsection Unary
1329:
1330: @c ?expressions operators unary
1331: @c ?operators unary
1332: @cindex unary
1333:
1334: The following is a list of all the unary operators and their usages:
1335:
1336:
1337: @example
1338: Symbol Example Explanation
1339: - -a unary minus
1340: + +a unary plus (no-operation)
1341: ~ ~a * one's complement
1342: ! !a * logical negation
1343: ! a! * factorial
1344: $ $3 * call arg/column during @ref{using} manipulation
1345:
1346: @end example
1347:
1348: (*) Starred explanations indicate that the operator requires an integer
1349: argument.
1350:
1351: Operator precedence is the same as in Fortran and C. As in those languages,
1352: parentheses may be used to change the order of operation. Thus -2**2 = -4,
1353: but (-2)**2 = 4.
1354:
1355: The factorial operator returns a real number to allow a greater range.
1356:
1357: @node Binary, Ternary, Unary, Operators
1358: @subsubsection Binary
1359:
1360: @c ?expressions operators binary
1361: @c ?operators binary
1362: @cindex binary
1363:
1364: The following is a list of all the binary operators and their usages:
1365:
1366:
1367: @example
1368: Symbol Example Explanation
1369: ** a**b exponentiation
1370: * a*b multiplication
1371: / a/b division
1372: % a%b * modulo
1373: + a+b addition
1374: - a-b subtraction
1375: == a==b equality
1376: != a!=b inequality
1377: < a<b less than
1378: <= a<=b less than or equal to
1379: > a>b greater than
1380: >= a>=b greater than or equal to
1381: & a&b * bitwise AND
1382: ^ a^b * bitwise exclusive OR
1383: | a|b * bitwise inclusive OR
1384: && a&&b * logical AND
1385: || a||b * logical OR
1386:
1387: @end example
1388:
1389:
1390: (*) Starred explanations indicate that the operator requires integer
1391: arguments.
1392:
1393: Logical AND (&&) and OR (||) short-circuit the way they do in C. That is,
1394: the second `&&` operand is not evaluated if the first is false; the second
1395: `||` operand is not evaluated if the first is true.
1396:
1397: @node Ternary, , Binary, Operators
1398: @subsubsection Ternary
1399:
1400: @c ?expressions operators ternary
1401: @c ?operators ternary
1402: @cindex ternary
1403:
1404: There is a single ternary operator:
1405:
1406:
1407: @example
1408: Symbol Example Explanation
1409: ?: a?b:c ternary operation
1410:
1411: @end example
1412:
1413:
1414: The ternary operator behaves as it does in C. The first argument (a), which
1415: must be an integer, is evaluated. If it is true (non-zero), the second
1416: argument (b) is evaluated and returned; otherwise the third argument (c) is
1417: evaluated and returned.
1418:
1419: The ternary operator is very useful both in constructing piecewise functions
1420: and in plotting points only when certain conditions are met.
1421:
1422: Examples:
1423:
1424: Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <= x < 2,
1425: and undefined elsewhere:
1426: @example
1427: f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
1428: plot f(x)
1429: @end example
1430:
1431: @c ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/ternary.gif" alt="[ternary.gif]" width=640 height=480>
1432: Note that `gnuplot` quietly ignores undefined values, so the final branch of
1433: the function (1/0) will produce no plottable points. Note also that f(x)
1434: will be plotted as a continuous function across the discontinuity if a line
1435: style is used. To plot it discontinuously, create separate functions for the
1436: two pieces. (Parametric functions are also useful for this purpose.)
1437:
1438: For data in a file, plot the average of the data in columns 2 and 3 against
1439: the datum in column 1, but only if the datum in column 4 is non-negative:
1440:
1441: @example
1442: plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )
1443:
1444: @end example
1445:
1446: Please see @ref{using} for an explanation of the @ref{using} syntax.
1447:
1448: @node User-defined, , Operators, Expressions
1449: @subsection User-defined
1450:
1451: @c ?expressions user-defined
1452: @cindex user-defined
1453:
1454: @cindex variables
1455: @opindex variables
1456:
1457:
1458: New user-defined variables and functions of one through five variables may
1459: be declared and used anywhere, including on the @ref{plot} command itself.
1460:
1461: User-defined function syntax:
1462: @example
1463: <func-name>( <dummy1> @{,<dummy2>@} ... @{,<dummy5>@} ) = <expression>
1464:
1465: @end example
1466:
1467: where <expression> is defined in terms of <dummy1> through <dummy5>.
1468:
1469: User-defined variable syntax:
1470: @example
1471: <variable-name> = <constant-expression>
1472:
1473: @end example
1474:
1475: Examples:
1476: @example
1477: w = 2
1478: q = floor(tan(pi/2 - 0.1))
1479: f(x) = sin(w*x)
1480: sinc(x) = sin(pi*x)/(pi*x)
1481: delta(t) = (t == 0)
1482: ramp(t) = (t > 0) ? t : 0
1483: min(a,b) = (a < b) ? a : b
1484: comb(n,k) = n!/(k!*(n-k)!)
1485: len3d(x,y,z) = sqrt(x*x+y*y+z*z)
1486: plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)
1487:
1488: @end example
1489:
1490: @c ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/userdefined.gif" alt="[userdefined.gif]" width=640 height=480>
1491: Note that the variable `pi` is already defined. But it is in no way magic;
1492: you may redefine it to be whatever you like.
1493:
1494: Valid names are the same as in most programming languages: they must begin
1495: with a letter, but subsequent characters may be letters, digits, "$", or "_".
1496: Note, however, that the `fit` mechanism uses several variables with names
1497: that begin "FIT_". It is safest to avoid using such names. "FIT_LIMIT",
1498: however, is one that you may wish to redefine. See the documentation
1499: on `fit` for details.
1500:
1501:
1502: See @ref{functions}, @ref{variables}, and `fit`.
1503:
1504: @node Glossary, Plotting, Expressions, gnuplot
1505: @section Glossary
1506:
1507: @cindex glossary
1508:
1509: Throughout this document an attempt has been made to maintain consistency of
1510: nomenclature. This cannot be wholly successful because as `gnuplot` has
1511: evolved over time, certain command and keyword names have been adopted that
1512: preclude such perfection. This section contains explanations of the way
1513: some of these terms are used.
1514:
1515: A "page" or "screen" is the entire area addressable by `gnuplot`. On a
1516: monitor, it is the full screen; on a plotter, it is a single sheet of paper.
1517:
1518: A screen may contain one or more "plots". A plot is defined by an abscissa
1519: and an ordinate, although these need not actually appear on it, as well as
1520: the margins and any text written therein.
1521:
1522: A plot contains one "graph". A graph is defined by an abscissa and an
1523: ordinate, although these need not actually appear on it.
1524:
1525: A graph may contain one or more "lines". A line is a single function or
1526: data set. "Line" is also a plotting style. The word will also be used in
1527: sense "a line of text". Presumably the context will remove any ambiguity.
1528:
1529: The lines on a graph may have individual names. These may be listed
1530: together with a sample of the plotting style used to represent them in
1531: the "key", sometimes also called the "legend".
1532:
1533: The word "title" occurs with multiple meanings in `gnuplot`. In this
1534: document, it will always be preceded by the adjective "plot", "line", or
1535: "key" to differentiate among them.
1536:
1537: A graph may have up to four labelled axes. Various commands have the name of
1538: an axis built into their names, such as @ref{xlabel}. Other commands have
1539: one or more axis names as options, such as `set logscale xy`. The names of
1540: the four axes for these usages are "x" for the axis along the bottom border
1541: of the plot, "y" for the left border, "x2" for the top border, and "y2" for
1542: the right border. "z" also occurs in commands used with 3-d plotting.
1543:
1544: When discussing data files, the term "record" will be resurrected and used
1545: to denote a single line of text in the file, that is, the characters between
1546: newline or end-of-record characters. A "point" is the datum extracted from
1547: a single record. A "datablock" is a set of points from consecutive records,
1548: delimited by blank records. A line, when referred to in the context of a
1549: data file, is a subset of a datablock.
1550:
1551: @node Plotting, Start-up, Glossary, gnuplot
1552: @section Plotting
1553:
1554: @cindex plotting
1555:
1556: There are three `gnuplot` commands which actually create a plot: @ref{plot},
1557: `splot` and @ref{replot}. @ref{plot} generates 2-d plots, `splot` generates 3-d
1558: plots (actually 2-d projections, of course), and @ref{replot} appends its
1559: arguments to the previous @ref{plot} or `splot` and executes the modified
1560: command.
1561:
1562: Much of the general information about plotting can be found in the discussion
1563: of @ref{plot}; information specific to 3-d can be found in the `splot` section.
1564:
1565: @ref{plot} operates in either rectangular or polar coordinates -- see `set polar`
1566: for details of the latter. `splot` operates only in rectangular coordinates,
1567: but the @ref{mapping} command allows for a few other coordinate systems to be
1568: treated. In addition, the @ref{using} option allows both @ref{plot} and `splot` to
1569: treat almost any coordinate system you'd care to define.
1570:
1571: `splot` can plot surfaces and contours in addition to points and/or lines.
1572: In addition to `splot`, see @ref{isosamples} for information about defining
1573: the grid for a 3-d function; `splot datafile` for information about the
1574: requisite file structure for 3-d data values; and @ref{contour} and @ref{cntrparam} for information about contours.
1575:
1576: @node Start-up, Substitution, Plotting, gnuplot
1577: @section Start-up
1578:
1579: @cindex startup
1580:
1581: @cindex start
1582:
1583: @cindex .gnuplot
1584:
1585: When `gnuplot` is run, it looks for an initialization file to load. This
1586: file is called `.gnuplot` on Unix and AmigaOS systems, and `GNUPLOT.INI` on
1587: other systems. If this file is not found in the current directory, the
1588: program will look for it in the home directory (under AmigaOS,
1589: Atari(single)TOS, MS-DOS and OS/2, the environment variable `gnuplot` should
1590: contain the name of this directory). Note: if NOCWDRC is defined during the
1591: installation, `gnuplot` will not read from the current directory.
1592:
1593: If the initialization file is found, `gnuplot` executes the commands in it.
1594: These may be any legal `gnuplot` commands, but typically they are limited to
1595: setting the terminal and defining frequently-used functions or variables.
1596:
1597: @node Substitution, Syntax, Start-up, gnuplot
1598: @section Substitution
1599:
1600: @cindex substitution
1601:
1602: Command-line substitution is specified by a system command enclosed in
1603: backquotes. This command is spawned and the output it produces replaces
1604: the name of the command (and backquotes) on the command line. Some
1605: implementations also support pipes; see @ref{special-filenames}.
1606:
1607: Newlines in the output produced by the spawned command are replaced with
1608: blanks.
1609:
1610: Command-line substitution can be used anywhere on the `gnuplot` command
1611: line.
1612:
1613: Example:
1614:
1615: This will run the program `leastsq` and replace `leastsq` (including
1616: backquotes) on the command line with its output:
1617: @example
1618: f(x) = `leastsq`
1619:
1620: @end example
1621:
1622: or, in VMS
1623: @example
1624: f(x) = `run leastsq`
1625:
1626: @end example
1627:
1628: @node Syntax, Time/Date_data, Substitution, gnuplot
1629: @section Syntax
1630:
1631: @cindex syntax
1632:
1633: @cindex specify
1634:
1635: @cindex punctuation
1636:
1637: The general rules of syntax and punctuation in `gnuplot` are that keywords
1638: and options are order-dependent. Options and any accompanying parameters are
1639: separated by spaces whereas lists and coordinates are separated by commas.
1640: Ranges are separated by colons and enclosed in brackets [], text and file
1641: names are enclosed in quotes, and a few miscellaneous things are enclosed
1642: in parentheses. Braces @{@} are used for a few special purposes.
1643:
1644: Commas are used to separate coordinates on the `set` commands @ref{arrow},
1645: @ref{key}, and @ref{label}; the list of variables being fitted (the list after the
1646: `via` keyword on the `fit` command); lists of discrete contours or the loop
1647: parameters which specify them on the @ref{cntrparam} command; the arguments
1648: of the `set` commands @ref{dgrid3d}, @ref{dummy}, @ref{isosamples}, @ref{offsets}, @ref{origin},
1649: @ref{samples}, @ref{size}, `time`, and @ref{view}; lists of tics or the loop parameters
1650: which specify them; the offsets for titles and axis labels; parametric
1651: functions to be used to calculate the x, y, and z coordinates on the @ref{plot},
1652: @ref{replot} and `splot` commands; and the complete sets of keywords specifying
1653: individual plots (data sets or functions) on the @ref{plot}, @ref{replot} and `splot`
1654: commands.
1655:
1656: Parentheses are used to delimit sets of explicit tics (as opposed to loop
1657: parameters) and to indicate computations in the @ref{using} filter of the `fit`,
1658: @ref{plot}, @ref{replot} and `splot` commands.
1659:
1660: (Parentheses and commas are also used as usual in function notation.)
1661:
1662: Brackets are used to delimit ranges, whether they are given on `set`, @ref{plot}
1663: or `splot` commands.
1664:
1665: Colons are used to separate extrema in `range` specifications (whether they
1666: are given on `set`, @ref{plot} or `splot` commands) and to separate entries in
1667: the @ref{using} filter of the @ref{plot}, @ref{replot}, `splot` and `fit` commands.
1668:
1669: Semicolons are used to separate commands given on a single command line.
1670:
1671: Braces are used in text to be specially processed by some terminals, like
1672: `postscript`. They are also used to denote complex numbers: @{3,2@} = 3 + 2i.
1673:
1674: Text may be enclosed in single- or double-quotes. Backslash processing of
1675: sequences like \n (newline) and \345 (octal character code) is performed for
1676: double-quoted strings, but not for single-quoted strings.
1677:
1678: The justification is the same for each line of a multi-line string. Thus the
1679: center-justified string
1680: @example
1681: "This is the first line of text.\nThis is the second line."
1682: @end example
1683:
1684: will produce
1685: @example
1686: This is the first line of text.
1687: This is the second line.
1688: @end example
1689:
1690: but
1691: @example
1692: 'This is the first line of text.\nThis is the second line.'
1693: @end example
1694:
1695: will produce
1696: @example
1697: This is the first line of text.\nThis is the second line.
1698:
1699: @end example
1700:
1701: Filenames may be entered with either single- or double-quotes. In this
1702: manual the command examples generally single-quote filenames and double-quote
1703: other string tokens for clarity.
1704:
1705: At present you should not embed \n inside @{@} when using the enhanced option
1706: of the postscript terminal.
1707:
1708: The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow a newline to be
1709: specified by \\ in a single-quoted string or \\\\ in a double-quoted string.
1710:
1711: Back-quotes are used to enclose system commands for substitution.
1712:
1713: @node Time/Date_data, , Syntax, gnuplot
1714: @section Time/Date data
1715:
1716: @cindex time/date
1717:
1718: `gnuplot` supports the use of time and/or date information as input data.
1719: This feature is activated by the commands `set xdata time`, `set ydata time`,
1720: etc.
1721:
1722: Internally all times and dates are converted to the number of seconds from
1723: the year 2000. The command @ref{timefmt} defines the format for all inputs:
1724: data files, ranges, tics, label positions---in short, anything that accepts a
1725: data value must receive it in this format. Since only one input format can
1726: be in force at a given time, all time/date quantities being input at the same
1727: time must be presented in the same format. Thus if both x and y data in a
1728: file are time/date, they must be in the same format.
1729:
1730: The conversion to and from seconds assumes Universal Time (which is the same
1731: as Greenwich Standard Time). There is no provision for changing the time
1732: zone or for daylight savings. If all your data refer to the same time zone
1733: (and are all either daylight or standard) you don't need to worry about these
1734: things. But if the absolute time is crucial for your application, you'll
1735: need to convert to UT yourself.
1736:
1737: Commands like @ref{xrange} will re-interpret the integer according to
1738: @ref{timefmt}. If you change @ref{timefmt}, and then `show` the quantity again, it
1739: will be displayed in the new @ref{timefmt}. For that matter, if you give the
1740: deactivation command (like @ref{xdata}), the quantity will be shown in its
1741: numerical form.
1742:
1743: The command `set format` defines the format that will be used for tic labels,
1744: whether or not the specified axis is time/date.
1745:
1746: If time/date information is to be plotted from a file, the @ref{using} option
1747: _must_ be used on the @ref{plot} or `splot` command. These commands simply use
1748: white space to separate columns, but white space may be embedded within the
1749: time/date string. If you use tabs as a separator, some trial-and-error may
1750: be necessary to discover how your system treats them.
1751:
1752: The following example demonstrates time/date plotting.
1753:
1754: Suppose the file "data" contains records like
1755:
1756: @example
1757: 03/21/95 10:00 6.02e23
1758:
1759: @end example
1760:
1761: This file can be plotted by
1762:
1763: @example
1764: set xdata time
1765: set timefmt "%m/%d/%y"
1766: set xrange ["03/21/95":"03/22/95"]
1767: set format x "%m/%d"
1768: set timefmt "%m/%d/%y %H:%M"
1769: plot "data" using 1:3
1770:
1771: @end example
1772:
1773: which will produce xtic labels that look like "03/21".
1774:
1775: See the descriptions of each command for more details.
1776:
1777: @node Commands, Graphical_User_Interfaces, gnuplot, Top
1778: @chapter Commands
1779:
1780: @cindex commands
1781:
1782: This section lists the commands acceptable to `gnuplot` in alphabetical
1783: order. Printed versions of this document contain all commands; on-line
1784: versions may not be complete. Indeed, on some systems there may be no
1785: commands at all listed under this heading.
1786:
1787: Note that in most cases unambiguous abbreviations for command names and their
1788: options are permissible, i.e., "`p f(x) w l`" instead of "`plot f(x) with
1789: lines`".
1790:
1791: In the syntax descriptions, braces (@{@}) denote optional arguments and a
1792: vertical bar (|) separates mutually exclusive choices.
1793:
1794: @menu
1795: * cd::
1796: * call::
1797: * clear::
1798: * exit::
1799: * fit::
1800: * help::
1801: * if::
1802: * load::
1803: * pause::
1804: * plot::
1805: * print::
1806: * pwd::
1807: * quit::
1808: * replot::
1809: * reread::
1810: * reset::
1811: * save::
1812: * set-show::
1813: * shell::
1814: * splot::
1815: * test::
1816: * update::
1817: @end menu
1818:
1819: @node cd, call, Commands, Commands
1820: @section cd
1821:
1822: @c ?commands cd
1823: @cindex cd
1824: @cmindex cd
1825:
1826:
1827: The @ref{cd} command changes the working directory.
1828:
1829: Syntax:
1830: @example
1831: cd '<directory-name>'
1832:
1833: @end example
1834:
1835: The directory name must be enclosed in quotes.
1836:
1837: Examples:
1838: @example
1839: cd 'subdir'
1840: cd ".."
1841:
1842: @end example
1843:
1844: DOS users _must_ use single-quotes---backslash [\] has special significance
1845: inside double-quotes. For example,
1846: @example
1847: cd "c:\newdata"
1848: @end example
1849:
1850: fails, but
1851: @example
1852: cd 'c:\newdata'
1853: @end example
1854:
1855: works as expected.
1856:
1857: @node call, clear, cd, Commands
1858: @section call
1859:
1860: @c ?commands call
1861: @cindex call
1862: @cmindex call
1863:
1864:
1865: The @ref{call} command is identical to the load command with one exception: you
1866: can have up to ten additional parameters to the command (delimited according
1867: to the standard parser rules) which can be substituted into the lines read
1868: from the file. As each line is read from the @ref{call}ed input file, it is
1869: scanned for the sequence `$` (dollar-sign) followed by a digit (0--9). If
1870: found, the sequence is replaced by the corresponding parameter from the
1871: @ref{call} command line. If the parameter was specified as a string in the
1872: @ref{call} line, it is substituted without its enclosing quotes. `$` followed by
1873: any character other than a digit will be that character. E.g. use `$$` to
1874: get a single `$`. Providing more than ten parameters on the @ref{call} command
1875: line will cause an error. A parameter that was not provided substitutes as
1876: nothing. Files being @ref{call}ed may themselves contain @ref{call} or @ref{load}
1877: commands.
1878:
1879: The @ref{call} command _must_ be the last command on a multi-command line.
1880:
1881: Syntax:
1882: @example
1883: call "<input-file>" <parameter-0> <parm-1> ... <parm-9>
1884:
1885: @end example
1886:
1887: The name of the input file must be enclosed in quotes, and it is recommended
1888: that parameters are similarly enclosed in quotes (future versions of gnuplot
1889: may treat quoted and unquoted arguments differently).
1890:
1891: Example:
1892:
1893: If the file 'calltest.gp' contains the line:
1894: @example
1895: print "p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"
1896:
1897: @end example
1898:
1899: entering the command:
1900: @example
1901: call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"
1902:
1903: @end example
1904:
1905: will display:
1906: @example
1907: p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx
1908:
1909: @end example
1910:
1911: NOTE: there is a clash in syntax with the datafile @ref{using} callback
1912: operator. Use `$$n` or `column(n)` to access column n from a datafile inside
1913: a @ref{call}ed datafile plot.
1914:
1915: @node clear, exit, call, Commands
1916: @section clear
1917:
1918: @c ?commands clear
1919: @cindex clear
1920: @cmindex clear
1921:
1922:
1923: The @ref{clear} command erases the current screen or output device as specified
1924: by @ref{output}. This usually generates a formfeed on hardcopy devices. Use
1925: @ref{terminal} to set the device type.
1926:
1927: For some terminals @ref{clear} erases only the portion of the plotting surface
1928: defined by @ref{size}, so for these it can be used in conjunction with @ref{multiplot} to create an inset.
1929:
1930: Example:
1931: @example
1932: set multiplot
1933: plot sin(x)
1934: set origin 0.5,0.5
1935: set size 0.4,0.4
1936: clear
1937: plot cos(x)
1938: set nomultiplot
1939:
1940: @end example
1941:
1942: Please see @ref{multiplot}, @ref{size}, and @ref{origin} for details of these
1943: commands.
1944:
1945: @node exit, fit, clear, Commands
1946: @section exit
1947:
1948: @c ?commands exit
1949: @cindex exit
1950: @cmindex exit
1951:
1952:
1953: The commands @ref{exit} and @ref{quit} and the END-OF-FILE character will exit the
1954: current `gnuplot` command file and @ref{load} the next one. See "help
1955: batch/interactive" for more details.
1956:
1957: Each of these commands will clear the output device (as does the @ref{clear}
1958: command) before exiting.
1959:
1960: @node fit, help, exit, Commands
1961: @section fit
1962:
1963: @c ?commands fit
1964: @cindex fit
1965: @cmindex fit
1966:
1967:
1968: @cindex least-squares
1969:
1970: @cindex Marquardt
1971:
1972: The `fit` command can fit a user-defined function to a set of data points
1973: (x,y) or (x,y,z), using an implementation of the nonlinear least-squares
1974: (NLLS) Marquardt-Levenberg algorithm. Any user-defined variable occurring in
1975: the function body may serve as a fit parameter, but the return type of the
1976: function must be real.
1977:
1978: Syntax:
1979: @example
1980: fit @{[xrange] @{[yrange]@}@} <function> '<datafile>'
1981: @{datafile-modifiers@}
1982: via '<parameter file>' | <var1>@{,<var2>,...@}
1983:
1984: @end example
1985:
1986: Ranges may be specified to temporarily limit the data which is to be fitted;
1987: any out-of-range data points are ignored. The syntax is
1988: @example
1989: [@{dummy_variable=@}@{<min>@}@{:<max>@}],
1990: @end example
1991:
1992: analogous to @ref{plot}; see @ref{ranges}.
1993:
1994: <function> is any valid `gnuplot` expression, although it is usual to use a
1995: previously user-defined function of the form f(x) or f(x,y).
1996:
1997: <datafile> is treated as in the @ref{plot} command. All the `plot datafile`
1998: modifiers (@ref{using}, @ref{every},...) except @ref{smooth} are applicable to `fit`.
1999: See `plot datafile`.
2000:
2001: The default data formats for fitting functions with a single independent
2002: variable, y=f(x), are @{x:@}y or x:y:s; those formats can be changed with
2003: the datafile @ref{using} qualifier. The third item, (a column number or an
2004: expression), if present, is interpreted as the standard deviation of the
2005: corresponding y value and is used to compute a weight for the datum, 1/s**2.
2006: Otherwise, all data points are weighted equally, with a weight of one.
2007:
2008: To fit a function with two independent variables, z=f(x,y), the required
2009: format is @ref{using} with four items, x:y:z:s. The complete format must be
2010: given---no default columns are assumed for a missing token. Weights for
2011: each data point are evaluated from 's' as above. If error estimates are
2012: not available, a constant value can be specified as a constant expression
2013: (see @ref{using}), e.g., `using 1:2:3:(1)`.
2014:
2015: Multiple datasets may be simultaneously fit with functions of one
2016: independent variable by making y a 'pseudo-variable', e.g., the dataline
2017: number, and fitting as two independent variables. See `fit multibranch`.
2018:
2019: The `via` qualifier specifies which parameters are to be adjusted, either
2020: directly, or by referencing a parameter file.
2021:
2022: Examples:
2023: @example
2024: f(x) = a*x**2 + b*x + c
2025: g(x,y) = a*x**2 + b*y**2 + c*x*y
2026: FIT_LIMIT = 1e-6
2027: fit f(x) 'measured.dat' via 'start.par'
2028: fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
2029: fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
2030: fit g(x,y) 'surface.dat' using 1:2:3:(1) via a, b, c
2031:
2032: @end example
2033:
2034: After each iteration step, detailed information about the current state
2035: of the fit is written to the display. The same information about the
2036: initial and final states is written to a log file, "fit.log". This file
2037: is always appended to, so as to not lose any previous fit history; it
2038: should be deleted or renamed as desired.
2039:
2040: The fit may be interrupted by pressing Ctrl-C (any key but Ctrl-C under
2041: MSDOS and Atari Multitasking Systems). After the current iteration
2042: completes, you have the option to (1) stop the fit and accept the current
2043: parameter values, (2) continue the fit, (3) execute a `gnuplot` command
2044: as specified by the environment variable FIT_SCRIPT. The default for
2045: FIT_SCRIPT is @ref{replot}, so if you had previously plotted both the data
2046: and the fitting function in one graph, you can display the current state
2047: of the fit.
2048:
2049: Once `fit` has finished, the @ref{update} command may be used to store final
2050: values in a file for subsequent use as a parameter file. See @ref{update}
2051: for details.
2052:
2053: @menu
2054: * adjustable_parameters::
2055: * beginner's_guide::
2056: * error_estimates::
2057: * fit_controlling::
2058: * multi-branch::
2059: * starting_values::
2060: * tips::
2061: @end menu
2062:
2063: @node adjustable_parameters, beginner's_guide, fit, fit
2064: @subsection adjustable parameters
2065:
2066: @c ?commands fit parameters
2067: @c ?fit parameters
2068: @c ?commands fit adjustable_parameters
2069: @c ?fit adjustable_parameters
2070: @cindex fit_parameters
2071:
2072: There are two ways that `via` can specify the parameters to be adjusted,
2073: either directly on the command line or indirectly, by referencing a
2074: parameter file. The two use different means to set initial values.
2075:
2076: Adjustable parameters can be specified by a comma-separated list of variable
2077: names after the `via` keyword. Any variable that is not already defined is
2078: is created with an initial value of 1.0. However, the fit is more likely
2079: to converge rapidly if the variables have been previously declared with more
2080: appropriate starting values.
2081:
2082: In a parameter file, each parameter to be varied and a corresponding initial
2083: value are specified, one per line, in the form
2084: @example
2085: varname = value
2086:
2087: @end example
2088:
2089: Comments, marked by '#', and blank lines are permissible. The
2090: special form
2091: @example
2092: varname = value # FIXED
2093:
2094: @end example
2095:
2096: means that the variable is treated as a 'fixed parameter', initialized by the
2097: parameter file, but not adjusted by `fit`. For clarity, it may be useful to
2098: designate variables as fixed parameters so that their values are reported by
2099: `fit`. The keyword `# FIXED` has to appear in exactly this form.
2100:
2101:
2102: @node beginner's_guide, error_estimates, adjustable_parameters, fit
2103: @subsection beginner's guide
2104:
2105: @c ?commands fit beginners_guide
2106: @c ?fit beginners_guide
2107: @c ?fit guide
2108: @cindex fitting
2109:
2110: `fit` is used to find a set of parameters that 'best' fits your data to your
2111: user-defined function. The fit is judged on the basis of the the sum of the
2112: squared differences or 'residuals' (SSR) between the input data points and
2113: the function values, evaluated at the same places. This quantity is often
2114: called 'chisquare' (i.e., the Greek letter chi, to the power of 2). The
2115: algorithm attempts to minimize SSR, or more precisely, WSSR, as the residuals
2116: are 'weighted' by the input data errors (or 1.0) before being squared; see
2117: `fit error_estimates` for details.
2118:
2119: That's why it is called 'least-squares fitting'. Let's look at an example
2120: to see what is meant by 'non-linear', but first we had better go over some
2121: terms. Here it is convenient to use z as the dependent variable for
2122: user-defined functions of either one independent variable, z=f(x), or two
2123: independent variables, z=f(x,y). A parameter is a user-defined variable
2124: that `fit` will adjust, i.e., an unknown quantity in the function
2125: declaration. Linearity/non-linearity refers to the relationship of the
2126: dependent variable, z, to the parameters which `fit` is adjusting, not of
2127: z to the independent variables, x and/or y. (To be technical, the
2128: second @{and higher@} derivatives of the fitting function with respect to
2129: the parameters are zero for a linear least-squares problem).
2130:
2131: For linear least-squares (LLS), the user-defined function will be a sum of
2132: simple functions, not involving any parameters, each multiplied by one
2133: parameter. NLLS handles more complicated functions in which parameters can
2134: be used in a large number of ways. An example that illustrates the
2135: difference between linear and nonlinear least-squares is the Fourier series.
2136: One member may be written as
2137: @example
2138: z=a*sin(c*x) + b*cos(c*x).
2139: @end example
2140:
2141: If a and b are the unknown parameters and c is constant, then estimating
2142: values of the parameters is a linear least-squares problem. However, if
2143: c is an unknown parameter, the problem is nonlinear.
2144:
2145: In the linear case, parameter values can be determined by comparatively
2146: simple linear algebra, in one direct step. However LLS is a special case
2147: which is also solved along with more general NLLS problems by the iterative
2148: procedure that `gnuplot` uses. `fit` attempts to find the minimum by doing
2149: a search. Each step (iteration) calculates WSSR with a new set of parameter
2150: values. The Marquardt-Levenberg algorithm selects the parameter values for
2151: the next iteration. The process continues until a preset criterium is met,
2152: either (1) the fit has "converged" (the relative change in WSSR is less than
2153: FIT_LIMIT), or (2) it reaches a preset iteration count limit, FIT_MAXITER
2154: (see @ref{variables}). The fit may also be interrupted
2155: and subsequently halted from the keyboard (see `fit`).
2156:
2157: Often the function to be fitted will be based on a model (or theory) that
2158: attempts to describe or predict the behaviour of the data. Then `fit` can
2159: be used to find values for the free parameters of the model, to determine
2160: how well the data fits the model, and to estimate an error range for each
2161: parameter. See `fit error_estimates`.
2162:
2163: Alternatively, in curve-fitting, functions are selected independent of
2164: a model (on the basis of experience as to which are likely to describe
2165: the trend of the data with the desired resolution and a minimum number
2166: of parameters*functions.) The `fit` solution then provides an analytic
2167: representation of the curve.
2168:
2169: However, if all you really want is a smooth curve through your data points,
2170: the @ref{smooth} option to @ref{plot} may be what you've been looking for rather
2171: than `fit`.
2172:
2173: @node error_estimates, fit_controlling, beginner's_guide, fit
2174: @subsection error estimates
2175:
2176: @c ?commands fit error_estimate
2177: @c ?fit error_estimate
2178: @c ?fit errors
2179: In `fit`, the term "error" is used in two different contexts, data error
2180: estimates and parameter error estimates.
2181:
2182: Data error estimates are used to calculate the relative weight of each data
2183: point when determining the weighted sum of squared residuals, WSSR or
2184: chisquare. They can affect the parameter estimates, since they determine
2185: how much influence the deviation of each data point from the fitted function
2186: has on the final values. Some of the `fit` output information, including
2187: the parameter error estimates, is more meaningful if accurate data error
2188: estimates have been provided.
2189:
2190: The 'statistical overview' describes some of the `fit` output and gives some
2191: background for the 'practical guidelines'.
2192:
2193: @menu
2194: * statistical_overview::
2195: * practical_guidelines::
2196: @end menu
2197:
2198: @node statistical_overview, practical_guidelines, error_estimates, error_estimates
2199: @subsubsection statistical overview
2200:
2201: @c ?commands fit error statistical_overview
2202: @c ?fit error statistical_overview
2203: @cindex statistical_overview
2204:
2205: The theory of non-linear least-squares (NLLS) is generally described in terms
2206: of a normal distribution of errors, that is, the input data is assumed to be
2207: a sample from a population having a given mean and a Gaussian (normal)
2208: distribution about the mean with a given standard deviation. For a sample of
2209: sufficiently large size, and knowing the population standard deviation, one
2210: can use the statistics of the chisquare distribution to describe a "goodness
2211: of fit" by looking at the variable often called "chisquare". Here, it is
2212: sufficient to say that a reduced chisquare (chisquare/degrees of freedom,
2213: where degrees of freedom is the number of datapoints less the number of
2214: parameters being fitted) of 1.0 is an indication that the weighted sum of
2215: squared deviations between the fitted function and the data points is the
2216: same as that expected for a random sample from a population characterized by
2217: the function with the current value of the parameters and the given standard
2218: deviations.
2219:
2220: If the standard deviation for the population is not constant, as in counting
2221: statistics where variance = counts, then each point should be individually
2222: weighted when comparing the observed sum of deviations and the expected sum
2223: of deviations.
2224:
2225: At the conclusion `fit` reports 'stdfit', the standard deviation of the fit,
2226: which is the rms of the residuals, and the variance of the residuals, also
2227: called 'reduced chisquare' when the data points are weighted. The number of
2228: degrees of freedom (the number of data points minus the number of fitted
2229: parameters) is used in these estimates because the parameters used in
2230: calculating the residuals of the datapoints were obtained from the same data.
2231:
2232: To estimate confidence levels for the parameters, one can use the minimum
2233: chisquare obtained from the fit and chisquare statistics to determine the
2234: value of chisquare corresponding to the desired confidence level, but
2235: considerably more calculation is required to determine the combinations of
2236: parameters which produce such values.
2237:
2238: Rather than determine confidence intervals, `fit` reports parameter error
2239: estimates which are readily obtained from the variance-covariance matrix
2240: after the final iteration. By convention, these estimates are called
2241: "standard errors" or "asymptotic standard errors", since they are calculated
2242: in the same way as the standard errors (standard deviation of each parameter)
2243: of a linear least-squares problem, even though the statistical conditions for
2244: designating the quantity calculated to be a standard deviation are not
2245: generally valid for the NLLS problem. The asymptotic standard errors are
2246: generally over-optimistic and should not be used for determining confidence
2247: levels, but are useful for qualitative purposes.
2248:
2249: The final solution also produces a correlation matrix, which gives an
2250: indication of the correlation of parameters in the region of the solution;
2251: if one parameter is changed, increasing chisquare, does changing another
2252: compensate? The main diagonal elements, autocorrelation, are all 1; if
2253: all parameters were independent, all other elements would be nearly 0. Two
2254: variables which completely compensate each other would have an off-diagonal
2255: element of unit magnitude, with a sign depending on whether the relation is
2256: proportional or inversely proportional. The smaller the magnitudes of the
2257: off-diagonal elements, the closer the estimates of the standard deviation
2258: of each parameter would be to the asymptotic standard error.
2259:
2260: @node practical_guidelines, , statistical_overview, error_estimates
2261: @subsubsection practical guidelines
2262:
2263: @c ?commands fit error practical_guidelines
2264: @c ?fit error practical_guidelines
2265: @cindex practical_guidelines
2266:
2267: @cindex guidelines
2268:
2269: If you have a basis for assigning weights to each data point, doing so lets
2270: you make use of additional knowledge about your measurements, e.g., take into
2271: account that some points may be more reliable than others. That may affect
2272: the final values of the parameters.
2273:
2274: Weighting the data provides a basis for interpreting the additional `fit`
2275: output after the last iteration. Even if you weight each point equally,
2276: estimating an average standard deviation rather than using a weight of 1
2277: makes WSSR a dimensionless variable, as chisquare is by definition.
2278:
2279: Each fit iteration will display information which can be used to evaluate
2280: the progress of the fit. (An '*' indicates that it did not find a smaller
2281: WSSR and is trying again.) The 'sum of squares of residuals', also called
2282: 'chisquare', is the WSSR between the data and your fitted function; `fit`
2283: has minimized that. At this stage, with weighted data, chisquare is expected
2284: to approach the number of degrees of freedom (data points minus parameters).
2285: The WSSR can be used to calculate the reduced chisquare (WSSR/ndf) or stdfit,
2286: the standard deviation of the fit, sqrt(WSSR/ndf). Both of these are
2287: reported for the final WSSR.
2288:
2289: If the data are unweighted, stdfit is the rms value of the deviation of the
2290: data from the fitted function, in user units.
2291:
2292: If you supplied valid data errors, the number of data points is large enough,
2293: and the model is correct, the reduced chisquare should be about unity. (For
2294: details, look up the 'chi-squared distribution' in your favourite statistics
2295: reference.) If so, there are additional tests, beyond the scope of this
2296: overview, for determining how well the model fits the data.
2297:
2298: A reduced chisquare much larger than 1.0 may be due to incorrect data error
2299: estimates, data errors not normally distributed, systematic measurement
2300: errors, 'outliers', or an incorrect model function. A plot of the residuals,
2301: e.g., `plot 'datafile' using 1:($2-f($1))`, may help to show any systematic
2302: trends. Plotting both the data points and the function may help to suggest
2303: another model.
2304:
2305: Similarly, a reduced chisquare less than 1.0 indicates WSSR is less than that
2306: expected for a random sample from the function with normally distributed
2307: errors. The data error estimates may be too large, the statistical
2308: assumptions may not be justified, or the model function may be too general,
2309: fitting fluctuations in a particular sample in addition to the underlying
2310: trends. In the latter case, a simpler function may be more appropriate.
2311:
2312: You'll have to get used to both `fit` and the kind of problems you apply it
2313: to before you can relate the standard errors to some more practical estimates
2314: of parameter uncertainties or evaluate the significance of the correlation
2315: matrix.
2316:
2317: Note that `fit`, in common with most NLLS implementations, minimizes the
2318: weighted sum of squared distances (y-f(x))**2. It does not provide any means
2319: to account for "errors" in the values of x, only in y. Also, any "outliers"
2320: (data points outside the normal distribution of the model) will have an
2321: exaggerated effect on the solution.
2322:
2323: @node fit_controlling, multi-branch, error_estimates, fit
2324: @subsection fit controlling
2325:
2326: @c ?commands fit_control
2327: @cindex fit_control
2328:
2329: @c ?fit control
2330: There are a number of `gnuplot` variables that can be defined to affect
2331: `fit`. Those which can be defined once `gnuplot` is running are listed
2332: under 'control_variables' while those defined before starting `gnuplot`
2333: are listed under 'environment_variables'.
2334:
2335: @menu
2336: * control_variables::
2337: * environment_variables::
2338: @end menu
2339:
2340: @node control_variables, environment_variables, fit_controlling, fit_controlling
2341: @subsubsection control variables
2342:
2343: @c ?commands fit_control variables
2344: @c ?fit_control variables
2345: @c ?fit control variables
2346: The default epsilon limit (1e-5) may be changed by declaring a value for
2347: @example
2348: FIT_LIMIT
2349: @end example
2350:
2351: When the sum of squared residuals changes between two iteration steps by
2352: a factor less than this number (epsilon), the fit is considered to have
2353: 'converged'.
2354:
2355: The maximum number of iterations may be limited by declaring a value for
2356: @example
2357: FIT_MAXITER
2358: @end example
2359:
2360: A value of 0 (or not defining it at all) means that there is no limit.
2361:
2362: If you need even more control about the algorithm, and know the
2363: Marquardt-Levenberg algorithm well, there are some more variables to
2364: influence it. The startup value of `lambda` is normally calculated
2365: automatically from the ML-matrix, but if you want to, you may provide
2366: your own one with
2367: @example
2368: FIT_START_LAMBDA
2369: @end example
2370:
2371: Specifying FIT_START_LAMBDA as zero or less will re-enable the automatic
2372: selection. The variable
2373: @example
2374: FIT_LAMBDA_FACTOR
2375: @end example
2376:
2377: gives the factor by which `lambda` is increased or decreased whenever
2378: the chi-squared target function increased or decreased significantly.
2379: Setting FIT_LAMBDA_FACTOR to zero re-enables the default factor of
2380: 10.0.
2381:
2382: Oher variables with the FIT_ prefix may be added to `fit`, so it is safer
2383: not to use that prefix for user-defined variables.
2384:
2385: The variables FIT_SKIP and FIT_INDEX were used by earlier releases of
2386: `gnuplot` with a 'fit' patch called `gnufit` and are no longer available.
2387: The datafile @ref{every} modifier provides the functionality of FIT_SKIP.
2388: FIT_INDEX was used for multi-branch fitting, but multi-branch fitting of
2389: one independent variable is now done as a pseudo-3D fit in which the
2390: second independent variable and @ref{using} are used to specify the branch.
2391: See @ref{multi-branch}.
2392:
2393: @node environment_variables, , control_variables, fit_controlling
2394: @subsubsection environment variables
2395:
2396: @c ?commands fit_control environment
2397: @c ?fit_control environment
2398: @c ?fit control environment
2399: The environment variables must be defined before `gnuplot` is executed; how
2400: to do so depends on your operating system.
2401:
2402: @example
2403: FIT_LOG
2404: @end example
2405:
2406: changes the name (and/or path) of the file to which the fit log will be
2407: written from the default of "fit.log" in the working directory.
2408:
2409: @example
2410: FIT_SCRIPT
2411: @end example
2412:
2413: specifies a command that may be executed after an user interrupt. The default
2414: is @ref{replot}, but a @ref{plot} or @ref{load} command may be useful to display a plot
2415: customized to highlight the progress of the fit.
2416:
2417: @node multi-branch, starting_values, fit_controlling, fit
2418: @subsection multi-branch
2419:
2420: @c ?commands fit multi-branch
2421: @c ?fit multi-branch
2422: @cindex multi-branch
2423:
2424: @cindex branch
2425:
2426: In multi-branch fitting, multiple data sets can be simultaneously fit with
2427: functions of one independent variable having common parameters by minimizing
2428: the total WSSR. The function and parameters (branch) for each data set are
2429: selected by using a 'pseudo-variable', e.g., either the dataline number (a
2430: 'column' index of -1) or the datafile index (-2), as the second independent
2431: variable.
2432:
2433: Example: Given two exponential decays of the form, z=f(x), each describing
2434: a different data set but having a common decay time, estimate the values of
2435: the parameters. If the datafile has the format x:z:s, then
2436: @example
2437: f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
2438: fit f(x,y) 'datafile' using 1:-1:2:3 via a, b, tau
2439:
2440: @end example
2441:
2442: For a more complicated example, see the file "hexa.fnc" used by the
2443: "fit.dem" demo.
2444:
2445: Appropriate weighting may be required since unit weights may cause one
2446: branch to predominate if there is a difference in the scale of the dependent
2447: variable. Fitting each branch separately, using the multi-branch solution
2448: as initial values, may give an indication as to the relative effect of each
2449: branch on the joint solution.
2450:
2451: @node starting_values, tips, multi-branch, fit
2452: @subsection starting values
2453:
2454: @c ?commands fit starting_values
2455: @c ?fit starting_values
2456: @cindex starting_values
2457:
2458: Nonlinear fitting is not guaranteed to converge to the global optimum (the
2459: solution with the smallest sum of squared residuals, SSR), and can get stuck
2460: at a local minimum. The routine has no way to determine that; it is up to
2461: you to judge whether this has happened.
2462:
2463: `fit` may, and often will get "lost" if started far from a solution, where
2464: SSR is large and changing slowly as the parameters are varied, or it may
2465: reach a numerically unstable region (e.g., too large a number causing a
2466: floating point overflow) which results in an "undefined value" message
2467: or `gnuplot` halting.
2468:
2469: To improve the chances of finding the global optimum, you should set the
2470: starting values at least roughly in the vicinity of the solution, e.g.,
2471: within an order of magnitude, if possible. The closer your starting values
2472: are to the solution, the less chance of stopping at another minimum. One way
2473: to find starting values is to plot data and the fitting function on the same
2474: graph and change parameter values and @ref{replot} until reasonable similarity
2475: is reached. The same plot is also useful to check whether the fit stopped at
2476: a minimum with a poor fit.
2477:
2478: Of course, a reasonably good fit is not proof there is not a "better" fit (in
2479: either a statistical sense, characterized by an improved goodness-of-fit
2480: criterion, or a physical sense, with a solution more consistent with the
2481: model.) Depending on the problem, it may be desirable to `fit` with various
2482: sets of starting values, covering a reasonable range for each parameter.
2483:
2484: @node tips, , starting_values, fit
2485: @subsection tips
2486:
2487: @c ?commands fit tips
2488: @c ?fit tips
2489: @cindex tips
2490:
2491: Here are some tips to keep in mind to get the most out of `fit`. They're not
2492: very organized, so you'll have to read them several times until their essence
2493: has sunk in.
2494:
2495: The two forms of the `via` argument to `fit` serve two largely distinct
2496: purposes. The `via "file"` form is best used for (possibly unattended) batch
2497: operation, where you just supply the startup values in a file and can later
2498: use @ref{update} to copy the results back into another (or the same) parameter
2499: file.
2500:
2501: The `via var1, var2, ...` form is best used interactively, where the command
2502: history mechanism may be used to edit the list of parameters to be fitted or
2503: to supply new startup values for the next try. This is particularly useful
2504: for hard problems, where a direct fit to all parameters at once won't work
2505: without good starting values. To find such, you can iterate several times,
2506: fitting only some of the parameters, until the values are close enough to the
2507: goal that the final fit to all parameters at once will work.
2508:
2509: Make sure that there is no mutual dependency among parameters of the function
2510: you are fitting. For example, don't try to fit a*exp(x+b), because
2511: a*exp(x+b)=a*exp(b)*exp(x). Instead, fit either a*exp(x) or exp(x+b).
2512:
2513: A technical issue: the parameters must not be too different in magnitude.
2514: The larger the ratio of the largest and the smallest absolute parameter
2515: values, the slower the fit will converge. If the ratio is close to or above
2516: the inverse of the machine floating point precision, it may take next to
2517: forever to converge, or refuse to converge at all. You will have to adapt
2518: your function to avoid this, e.g., replace 'parameter' by '1e9*parameter' in
2519: the function definition, and divide the starting value by 1e9.
2520:
2521: If you can write your function as a linear combination of simple functions
2522: weighted by the parameters to be fitted, by all means do so. That helps a
2523: lot, because the problem is no longer nonlinear and should converge with only
2524: a small number of iterations, perhaps just one.
2525:
2526: Some prescriptions for analysing data, given in practical experimentation
2527: courses, may have you first fit some functions to your data, perhaps in a
2528: multi-step process of accounting for several aspects of the underlying
2529: theory one by one, and then extract the information you really wanted from
2530: the fitting parameters of those functions. With `fit`, this may often be
2531: done in one step by writing the model function directly in terms of the
2532: desired parameters. Transforming data can also quite often be avoided,
2533: though sometimes at the cost of a more difficult fit problem. If you think
2534: this contradicts the previous paragraph about simplifying the fit function,
2535: you are correct.
2536:
2537: A "singular matrix" message indicates that this implementation of the
2538: Marquardt-Levenberg algorithm can't calculate parameter values for the next
2539: iteration. Try different starting values, writing the function in another
2540: form, or a simpler function.
2541:
2542: Finally, a nice quote from the manual of another fitting package (fudgit),
2543: that kind of summarizes all these issues: "Nonlinear fitting is an art!"
2544:
2545: @node help, if, fit, Commands
2546: @section help
2547:
2548: @c ?commands help
2549: @cindex help
2550: @cmindex help
2551:
2552:
2553: The @ref{help} command displays on-line help. To specify information on a
2554: particular topic use the syntax:
2555:
2556: @example
2557: help @{<topic>@}
2558:
2559: @end example
2560:
2561: If <topic> is not specified, a short message is printed about `gnuplot`.
2562: After help for the requested topic is given, a menu of subtopics is given;
2563: help for a subtopic may be requested by typing its name, extending the help
2564: request. After that subtopic has been printed, the request may be extended
2565: again or you may go back one level to the previous topic. Eventually, the
2566: `gnuplot` command line will return.
2567:
2568: If a question mark (?) is given as the topic, the list of topics currently
2569: available is printed on the screen.
2570:
2571: @node if, load, help, Commands
2572: @section if
2573:
2574: @c ?commands if
2575: @cindex if
2576: @cmindex if
2577:
2578:
2579: The @ref{if} command allows commands to be executed conditionally.
2580:
2581: Syntax:
2582: @example
2583: if (<condition>) <command-line>
2584:
2585: @end example
2586:
2587: <condition> will be evaluated. If it is true (non-zero), then the command(s)
2588: of the <command-line> will be executed. If <condition> is false (zero), then
2589: the entire <command-line> is ignored. Note that use of `;` to allow multiple
2590: commands on the same line will _not_ end the conditionalized commands.
2591:
2592: Examples:
2593: @example
2594: pi=3
2595: if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1); print pi
2596: @end example
2597:
2598: will display:
2599: @example
2600: ?Fixing pi!
2601: 3.14159265358979
2602: @end example
2603:
2604: but
2605: @example
2606: if (1==2) print "Never see this"; print "Or this either"
2607: @end example
2608:
2609: will not display anything.
2610:
2611: See @ref{reread} for an example of how @ref{if} and @ref{reread} can be used together to
2612: perform a loop.
2613:
2614: @node load, pause, if, Commands
2615: @section load
2616:
2617: @c ?commands load
2618: @cindex load
2619: @cmindex load
2620:
2621:
2622: The @ref{load} command executes each line of the specified input file as if it
2623: had been typed in interactively. Files created by the @ref{save} command can
2624: later be @ref{load}ed. Any text file containing valid commands can be created
2625: and then executed by the @ref{load} command. Files being @ref{load}ed may themselves
2626: contain @ref{load} or @ref{call} commands. See `comment` for information about
2627: comments in commands. To @ref{load} with arguments, see @ref{call}.
2628:
2629: The @ref{load} command _must_ be the last command on a multi-command line.
2630:
2631: Syntax:
2632: @example
2633: load "<input-file>"
2634:
2635: @end example
2636:
2637: The name of the input file must be enclosed in quotes.
2638:
2639: The special filename "-" may be used to @ref{load} commands from standard input.
2640: This allows a `gnuplot` command file to accept some commands from standard
2641: input. Please see "help batch/interactive" for more details.
2642:
2643: Examples:
2644: @example
2645: load 'work.gnu'
2646: load "func.dat"
2647:
2648: @end example
2649:
2650: The @ref{load} command is performed implicitly on any file names given as
2651: arguments to `gnuplot`. These are loaded in the order specified, and
2652: then `gnuplot` exits.
2653:
2654: @node pause, plot, load, Commands
2655: @section pause
2656:
2657: @c ?commands pause
2658: @cindex pause
2659: @cmindex pause
2660:
2661:
2662: The @ref{pause} command displays any text associated with the command and then
2663: waits a specified amount of time or until the carriage return is pressed.
2664: @ref{pause} is especially useful in conjunction with @ref{load} files.
2665:
2666: Syntax:
2667: @example
2668: pause <time> @{"<string>"@}
2669:
2670: @end example
2671:
2672: <time> may be any integer constant or expression. Choosing -1 will wait
2673: until a carriage return is hit, zero (0) won't pause at all, and a positive
2674: integer will wait the specified number of seconds. `pause 0` is synonymous
2675: with @ref{print}.
2676:
2677: Note: Since @ref{pause} communicates with the operating system rather than the
2678: graphics, it may behave differently with different device drivers (depending
2679: upon how text and graphics are mixed).
2680:
2681: Examples:
2682: @example
2683: pause -1 # Wait until a carriage return is hit
2684: pause 3 # Wait three seconds
2685: pause -1 "Hit return to continue"
2686: pause 10 "Isn't this pretty? It's a cubic spline."
2687:
2688: @end example
2689:
2690:
2691: @node plot, print, pause, Commands
2692: @section plot
2693:
2694: @c ?commands plot
2695: @cindex plot
2696: @cmindex plot
2697:
2698:
2699: @ref{plot} is the primary command for drawing plots with `gnuplot`. It creates
2700: plots of functions and data in many, many ways. @ref{plot} is used to draw 2-d
2701: functions and data; `splot` draws 2-d projections of 3-d surfaces and data.
2702: @ref{plot} and `splot` contain many common features; see `splot` for differences.
2703: Note specifically that `splot`'s @ref{binary} and @ref{matrix} options do not exist
2704: for @ref{plot}.
2705:
2706: Syntax:
2707: @example
2708: plot @{<ranges>@}
2709: @{<function> | @{"<datafile>" @{datafile-modifiers@}@}@}
2710: @{axes <axes>@} @{<title-spec>@} @{with <style>@}
2711: @{, @{definitions,@} <function> ...@}
2712:
2713: @end example
2714:
2715: where either a <function> or the name of a data file enclosed in quotes is
2716: supplied. A function is a mathematical expression or a pair of mathematical
2717: expressions in parametric mode. The expressions may be defined completely or
2718: in part earlier in the stream of `gnuplot` commands (see `user-defined`).
2719:
2720: It is also possible to define functions and parameters on the @ref{plot} command
2721: itself. This is done merely by isolating them from other items with commas.
2722:
2723: There are four possible sets of axes available; the keyword <axes> is used to
2724: select the axes for which a particular line should be scaled. `x1y1` refers
2725: to the axes on the bottom and left; `x2y2` to those on the top and right;
2726: `x1y2` to those on the bottom and right; and `x2y1` to those on the top and
2727: left. Ranges specified on the @ref{plot} command apply only to the first set of
2728: axes (bottom left).
2729:
2730: Examples:
2731: @example
2732: plot sin(x)
2733: plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
2734: plot [t=1:10] [-pi:pi*2] tan(t), \
2735: "data.1" using (tan($2)):($3/$4) smooth csplines \
2736: axes x1y2 notitle with lines 5
2737:
2738: @end example
2739:
2740:
2741: @menu
2742: * data-file::
2743: * errorbars::
2744: * parametric::
2745: * ranges::
2746: * title::
2747: * with::
2748: @end menu
2749:
2750: @node data-file, errorbars, plot, plot
2751: @subsection data-file
2752:
2753: @c ?commands plot datafile
2754: @c ?plot datafile
2755: @cindex data-file
2756:
2757: @cindex datafile
2758:
2759: @cindex data
2760:
2761: Discrete data contained in a file can be displayed by specifying the name of
2762: the data file (enclosed in single or double quotes) on the @ref{plot} command line.
2763:
2764: Syntax:
2765: @example
2766: plot '<file_name>' @{index <index list>@}
2767: @{every <every list>@}
2768: @{thru <thru expression>@}
2769: @{using <using list>@}
2770: @{smooth <option>@}
2771:
2772: @end example
2773:
2774: The modifiers @ref{index}, @ref{every}, @ref{thru}, @ref{using}, and @ref{smooth} are discussed
2775: separately. In brief, @ref{index} selects which data sets in a multi-data-set
2776: file are to be plotted, @ref{every} specifies which points within a single data
2777: set are to be plotted, @ref{using} determines how the columns within a single
2778: record are to be interpreted (@ref{thru} is a special case of @ref{using}), and
2779: @ref{smooth} allows for simple interpolation and approximation. ('splot' has a
2780: similar syntax, but does not support the @ref{smooth} and @ref{thru} options.)
2781:
2782: Data files should contain at least one data point per record (@ref{using} can
2783: select one data point from the record). Records beginning with `#` (and
2784: also with `!` on VMS) will be treated as comments and ignored. Each data
2785: point represents an (x,y) pair. For @ref{plot}s with error bars (see @ref{errorbars}), each data point is (x,y,ydelta), (x,y,ylow,yhigh), (x,y,xdelta),
2786: (x,y,xlow,xhigh), or (x,y,xlow,xhigh,ylow,yhigh). In all cases, the numbers
2787: on each record of a data file must be separated by white space (one or more
2788: blanks or tabs), unless a format specifier is provided by the @ref{using} option.
2789: This white space divides each record into columns.
2790:
2791: Data may be written in exponential format with the exponent preceded by the
2792: letter e, E, d, D, q, or Q.
2793:
2794: Only one column (the y value) need be provided. If x is omitted, `gnuplot`
2795: provides integer values starting at 0.
2796:
2797: In datafiles, blank records (records with no characters other than blanks and
2798: a newline and/or carriage return) are significant---pairs of blank records
2799: separate @ref{index}es (see @ref{index}). Data separated by double
2800: blank records are treated as if they were in separate data files.
2801:
2802: Single blank records designate discontinuities in a @ref{plot}; no line will join
2803: points separated by a blank records (if they are plotted with a line style).
2804:
2805: If autoscaling has been enabled (@ref{autoscale}), the axes are automatically
2806: extended to include all datapoints, with a whole number of tic marks if tics
2807: are being drawn. This has two consequences: i) For `splot`, the corner of
2808: the surface may not coincide with the corner of the base. In this case, no
2809: vertical line is drawn. ii) When plotting data with the same x range on a
2810: dual-axis graph, the x coordinates may not coincide if the x2tics are not
2811: being drawn. This is because the x axis has been autoextended to a whole
2812: number of tics, but the x2 axis has not. The following example illustrates
2813: the problem:
2814:
2815: @example
2816: reset; plot '-', '-'
2817: 1 1
2818: 19 19
2819: e
2820: 1 1
2821: 19 19
2822: e
2823:
2824: @end example
2825:
2826: @menu
2827: * every::
2828: * example_datafile::
2829: * index::
2830: * smooth::
2831: * special-filenames::
2832: * thru::
2833: * using::
2834: @end menu
2835:
2836: @node every, example_datafile, data-file, data-file
2837: @subsubsection every
2838:
2839: @c ?commands plot datafile every
2840: @c ?plot datafile every
2841: @c ?plot every
2842: @c ?data-file every
2843: @c ?datafile every
2844: @cindex every
2845:
2846: The @ref{every} keyword allows a periodic sampling of a data set to be plotted.
2847:
2848: In the discussion a "point" is a datum defined by a single record in the
2849: file; "block" here will mean the same thing as "datablock" (see `glossary`).
2850:
2851: Syntax:
2852: @example
2853: plot 'file' every @{<point_incr>@}
2854: @{:@{<block_incr>@}
2855: @{:@{<start_point>@}
2856: @{:@{<start_block>@}
2857: @{:@{<end_point>@}
2858: @{:<end_block>@}@}@}@}@}
2859:
2860: @end example
2861:
2862: The data points to be plotted are selected according to a loop from
2863: <`start_point`> to <`end_point`> with increment <`point_incr`> and the
2864: blocks according to a loop from <`start_block`> to <`end_block`> with
2865: increment <`block_incr`>.
2866:
2867: The first datum in each block is numbered '0', as is the first block in the
2868: file.
2869:
2870: Note that records containing unplottable information are counted.
2871:
2872: Any of the numbers can be omitted; the increments default to unity, the start
2873: values to the first point or block, and the end values to the last point or
2874: block. If @ref{every} is not specified, all points in all lines are plotted.
2875:
2876: Examples:
2877: @example
2878: every :::3::3 # selects just the fourth block ('0' is first)
2879: every :::::9 # selects the first 10 blocks
2880: every 2:2 # selects every other point in every other block
2881: every ::5::15 # selects points 5 through 15 in each block
2882: @end example
2883:
2884: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/simple.html,Simple Plot Demos },
2885: @uref{http://www.nas.nasa.gov/~woo/gnuplot/surfacea/surfacea.html,Non-parametric splot demos }, and
2886: @uref{http://www.nas.nasa.gov/~woo/gnuplot/surfaceb/surfaceb.html,Parametric splot demos.}
2887:
2888: @node example_datafile, index, every, data-file
2889: @subsubsection example datafile
2890:
2891: @c ?commands plot datafile example
2892: @c ?plot datafile example
2893: @c ?plot example
2894: @c ?datafile example
2895: @c ?data-file example
2896: @cindex example
2897:
2898: This example plots the data in the file "population.dat" and a theoretical
2899: curve:
2900:
2901: @example
2902: pop(x) = 103*exp((1965-x)/10)
2903: plot [1960:1990] 'population.dat', pop(x)
2904:
2905: @end example
2906:
2907: The file "population.dat" might contain:
2908:
2909: @example
2910: # Gnu population in Antarctica since 1965
2911: 1965 103
2912: 1970 55
2913: 1975 34
2914: 1980 24
2915: 1985 10
2916:
2917: @end example
2918:
2919: @c ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/population.gif" alt="[population.gif]" width=640 height=480>
2920:
2921: @node index, smooth, example_datafile, data-file
2922: @subsubsection index
2923:
2924: @c ?commands plot datafile index
2925: @c ?plot datafile index
2926: @c ?plot index
2927: @c ?data-file index
2928: @c ?datafile index
2929: @cindex index
2930:
2931: The @ref{index} keyword allows only some of the data sets in a multi-data-set
2932: file to be plotted.
2933:
2934: Syntax:
2935: @example
2936: plot 'file' index <m>@{@{:<n>@}:<p>@}
2937:
2938: @end example
2939:
2940: Data sets are separated by pairs of blank records. `index <m>` selects only
2941: set <m>; `index <m>:<n>` selects sets in the range <m> to <n>; and `index
2942: <m>:<n>:<p>` selects indices <m>, <m>+<p>, <m>+2<p>, etc., but stopping at
2943: <n>. Following C indexing, the index 0 is assigned to the first data set in
2944: the file. Specifying too large an index results in an error message. If
2945: @ref{index} is not specified, all sets are plotted as a single data set.
2946:
2947: Example:
2948: @example
2949: plot 'file' index 4:5
2950: @end example
2951:
2952: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/multimsh.html,splot with indices demo. }
2953:
2954: @node smooth, special-filenames, index, data-file
2955: @subsubsection smooth
2956:
2957: @c ?commands plot datafile smooth
2958: @c ?plot datafile smooth
2959: @c ?plot smooth
2960: @c ?data-file smooth
2961: @c ?datafile smooth
2962: @cindex smooth
2963:
2964: `gnuplot` includes a few general-purpose routines for interpolation and
2965: approximation of data; these are grouped under the @ref{smooth} option. More
2966: sophisticated data processing may be performed by preprocessing the data
2967: externally or by using `fit` with an appropriate model.
2968:
2969: Syntax:
2970: @example
2971: smooth @{unique | csplines | acsplines | bezier | sbezier@}
2972:
2973: @end example
2974:
2975: `unique` plots the data after making them monotonic. Each of the other
2976: routines uses the data to determine the coefficients of a continuous curve
2977: between the endpoints of the data. This curve is then plotted in the same
2978: manner as a function, that is, by finding its value at uniform intervals
2979: along the abscissa (see @ref{samples}) and connecting these points with
2980: straight line segments (if a line style is chosen).
2981:
2982: If @ref{autoscale} is in effect, the ranges will be computed such that the
2983: plotted curve lies within the borders of the graph.
2984:
2985: If too few points are available to allow the selected option to be applied,
2986: an error message is produced. The minimum number is one for `unique`, four
2987: for `acsplines`, and three for the others.
2988:
2989: The @ref{smooth} options have no effect on function plots.
2990:
2991:
2992: @noindent --- ACSPLINES ---
2993:
2994: @c ?commands plot datafile smooth acsplines
2995: @c ?plot datafile smooth acsplines
2996: @c ?data-file smooth acsplines
2997: @c ?datafile smooth acsplines
2998: @c ?plot smooth acsplines
2999: @c ?plot acsplines
3000: @c ?smooth acsplines
3001: @cindex acsplines
3002:
3003: The `acsplines` option approximates the data with a "natural smoothing spline".
3004: After the data are made monotonic in x (see `smooth unique`), a curve is
3005: piecewise constructed from segments of cubic polynomials whose coefficients
3006: are found by the weighting the data points; the weights are taken from the
3007: third column in the data file. That default can be modified by the third
3008: entry in the @ref{using} list, e.g.,
3009: @example
3010: plot 'data-file' using 1:2:(1.0) smooth acsplines
3011:
3012: @end example
3013:
3014: Qualitatively, the absolute magnitude of the weights determines the number
3015: of segments used to construct the curve. If the weights are large, the
3016: effect of each datum is large and the curve approaches that produced by
3017: connecting consecutive points with natural cubic splines. If the weights are
3018: small, the curve is composed of fewer segments and thus is smoother; the
3019: limiting case is the single segment produced by a weighted linear least
3020: squares fit to all the data. The smoothing weight can be expressed in terms
3021: of errors as a statistical weight for a point divided by a "smoothing factor"
3022: for the curve so that (standard) errors in the file can be used as smoothing
3023: weights.
3024:
3025: Example:
3026: @example
3027: sw(x,S)=1/(x*x*S)
3028: plot 'data_file' using 1:2:(sw($3,100)) smooth acsplines
3029:
3030: @end example
3031:
3032:
3033: @noindent --- BEZIER ---
3034:
3035: @c ?commands plot datafile smooth bezier
3036: @c ?plot datafile smooth bezier
3037: @c ?plot smooth bezier
3038: @c ?data-file smooth bezier
3039: @c ?datafile smooth bezier
3040: @c ?plot bezier
3041: @c ?smooth bezier
3042: @cindex bezier
3043:
3044: The `bezier` option approximates the data with a Bezier curve of degree n
3045: (the number of data points) that connects the endpoints.
3046:
3047:
3048: @noindent --- CSPLINES ---
3049:
3050: @c ?commands plot datafile smooth csplines
3051: @c ?plot datafile smooth csplines
3052: @c ?plot smooth csplines
3053: @c ?data-file smooth csplines
3054: @c ?datafile smooth csplines
3055: @c ?plot csplines
3056: @c ?smooth csplines
3057: @cindex csplines
3058:
3059: The `csplines` option connects consecutive points by natural cubic splines
3060: after rendering the data monotonic (see `smooth unique`).
3061:
3062:
3063: @noindent --- SBEZIER ---
3064:
3065: @c ?commands plot datafile smooth sbezier
3066: @c ?plot datafile smooth sbezier
3067: @c ?plot smooth sbezier
3068: @c ?data-file smooth sbezier
3069: @c ?datafile smooth sbezier
3070: @c ?plot sbezier
3071: @c ?smooth sbezier
3072: @cindex sbezier
3073:
3074: The `sbezier` option first renders the data monotonic (`unique`) and then
3075: applies the `bezier` algorithm.
3076:
3077:
3078: @noindent --- UNIQUE ---
3079:
3080: @c ?commands plot datafile smooth unique
3081: @c ?plot datafile smooth unique
3082: @c ?plot smooth unique
3083: @c ?data-file smooth unique
3084: @c ?datafile smooth unique
3085: @c ?plot unique
3086: @c ?smooth unique
3087: @cindex unique
3088:
3089: The `unique` option makes the data monotonic in x; points with the same
3090: x-value are replaced by a single point having the average y-value. The
3091: resulting points are then connected by straight line segments.
3092: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/mgr.html,See demos. }
3093:
3094: @node special-filenames, thru, smooth, data-file
3095: @subsubsection special-filenames
3096:
3097: @c ?commands plot datafile special-filenames
3098: @c ?plot datafile special-filenames
3099: @c ?plot special-filenames
3100: @c ?datafile special-filenames
3101: @cindex special-filenames
3102:
3103: A special filename of `'-'` specifies that the data are inline; i.e., they
3104: follow the command. Only the data follow the command; @ref{plot} options like
3105: filters, titles, and line styles remain on the 'plot' command line. This is
3106: similar to << in unix shell script, and $DECK in VMS DCL. The data are
3107: entered as though they are being read from a file, one data point per record.
3108: The letter "e" at the start of the first column terminates data entry. The
3109: @ref{using} option can be applied to these data---using it to filter them through
3110: a function might make sense, but selecting columns probably doesn't!
3111:
3112: `'-'` is intended for situations where it is useful to have data and commands
3113: together, e.g., when `gnuplot` is run as a sub-process of some front-end
3114: application. Some of the demos, for example, might use this feature. While
3115: @ref{plot} options such as @ref{index} and @ref{every} are recognized, their use forces
3116: you to enter data that won't be used. For example, while
3117:
3118: @example
3119: plot '-' index 0, '-' index 1
3120: 2
3121: 4
3122: 6
3123:
3124: @end example
3125:
3126:
3127: @example
3128: 10
3129: 12
3130: 14
3131: e
3132: 2
3133: 4
3134: 6
3135:
3136: @end example
3137:
3138:
3139: @example
3140: 10
3141: 12
3142: 14
3143: e
3144:
3145: @end example
3146:
3147: does indeed work,
3148:
3149: @example
3150: plot '-', '-'
3151: 2
3152: 4
3153: 6
3154: e
3155: 10
3156: 12
3157: 14
3158: e
3159:
3160: @end example
3161:
3162: is a lot easier to type.
3163:
3164: If you use `'-'` with @ref{replot}, you may need to enter the data more than once
3165: (see @ref{replot}).
3166:
3167: A blank filename ('') specifies that the previous filename should be reused.
3168: This can be useful with things like
3169:
3170: @example
3171: plot 'a/very/long/filename' using 1:2, '' using 1:3, '' using 1:4
3172:
3173: @end example
3174:
3175: (If you use both `'-'` and `''` on the same @ref{plot} command, you'll need to
3176: have two sets of inline data, as in the example above.)
3177:
3178: On some computer systems with a popen function (Unix), the datafile can be
3179: piped through a shell command by starting the file name with a '<'. For
3180: example,
3181:
3182: @example
3183: pop(x) = 103*exp(-x/10)
3184: plot "< awk '@{print $1-1965, $2@}' population.dat", pop(x)
3185:
3186: @end example
3187:
3188: would plot the same information as the first population example but with
3189: years since 1965 as the x axis. If you want to execute this example, you
3190: have to delete all comments from the data file above or substitute the
3191: following command for the first part of the command above (the part up to
3192: the comma):
3193:
3194: @example
3195: plot "< awk '$0 !~ /^#/ @{print $1-1965, $2@}' population.dat"
3196:
3197: @end example
3198:
3199: While this approach is most flexible, it is possible to achieve simple
3200: filtering with the @ref{using} or @ref{thru} keywords.
3201:
3202: @node thru, using, special-filenames, data-file
3203: @subsubsection thru
3204:
3205: @c ?commands plot datafile thru
3206: @c ?plot datafile thru
3207: @c ?plot thru
3208: @c ?data-file thru
3209: @c ?datafile thru
3210: @cindex thru
3211:
3212: The @ref{thru} function is provided for backward compatibility.
3213:
3214: Syntax:
3215: @example
3216: plot 'file' thru f(x)
3217:
3218: @end example
3219:
3220: It is equivalent to:
3221:
3222: @example
3223: plot 'file' using 1:(f($2))
3224:
3225: @end example
3226:
3227: While the latter appears more complex, it is much more flexible. The more
3228: natural
3229:
3230: @example
3231: plot 'file' thru f(y)
3232:
3233: @end example
3234:
3235: also works (i.e. you can use y as the dummy variable).
3236:
3237: @ref{thru} is parsed for `splot` and `fit` but has no effect.
3238:
3239: @node using, , thru, data-file
3240: @subsubsection using
3241:
3242: @c ?commands plot datafile using
3243: @c ?plot datafile using
3244: @c ?plot using
3245: @c ?data-file using
3246: @c ?datafile using
3247: @cindex using
3248:
3249: The most common datafile modifier is @ref{using}.
3250:
3251: Syntax:
3252: @example
3253: plot 'file' using @{<entry> @{:<entry> @{:<entry> ...@}@}@} @{'format'@}
3254:
3255: @end example
3256:
3257: If a format is specified, each datafile record is read using the C library's
3258: 'scanf' function, with the specified format string. Otherwise the record is
3259: read and broken into columns at spaces or tabs. A format cannot be specified
3260: if time-format data is being used (this must be done by `set data time`).
3261:
3262: The resulting array of data is then sorted into columns according to the
3263: entries. Each <entry> may be a simple column number, which selects the
3264: datum, an expression enclosed in parentheses, or empty. The expression can
3265: use $1 to access the first item read, $2 for the second item, and so on. It
3266: can also use `column(x)` and `valid(x)` where x is an arbitrary expression
3267: resulting in an integer. `column(x)` returns the x'th datum; `valid(x)`
3268: tests that the datum in the x'th column is a valid number. A column number
3269: of 0 generates a number increasing (from zero) with each point, and is reset
3270: upon encountering two blank records. A column number of -1 gives the
3271: dataline number, which starts at 0, increments at single blank records, and
3272: is reset at double blank records. A column number of -2 gives the index
3273: number, which is incremented only when two blank records are found. An empty
3274: <entry> will default to its order in the list of entries. For example,
3275: `using ::4` is interpreted as `using 1:2:4`.
3276:
3277: N.B.---the @ref{call} command also uses $'s as a special character. See @ref{call}
3278: for details about how to include a column number in a @ref{call} argument list.
3279:
3280: If the @ref{using} list has but a single entry, that <entry> will be used for y
3281: and the data point number is used for x; for example, "`plot 'file' using 1`"
3282: is identical to "`plot 'file' using 0:1`". If the @ref{using} list has two
3283: entries, these will be used for x and y. Additional entries are usually
3284: errors in x and/or y. See @ref{style} for details about plotting styles that
3285: make use of error information, and `fit` for use of error information in
3286: curve fitting.
3287:
3288: 'scanf' accepts several numerical specifications but `gnuplot` requires all
3289: inputs to be double-precision floating-point variables, so `lf` is the only
3290: permissible specifier. 'scanf' expects to see white space---a blank, tab
3291: ("\t"), newline ("\n"), or formfeed ("\f")---between numbers; anything else
3292: in the input stream must be explicitly skipped.
3293:
3294: Note that the use of "\t", "\n", or "\f" or requires use of double-quotes
3295: rather than single-quotes.
3296:
3297: Examples:
3298:
3299: This creates a plot of the sum of the 2nd and 3rd data against the first:
3300: (The format string specifies comma- rather than space-separated columns.)
3301: @example
3302: plot 'file' using 1:($2+$3) '%lf,%lf,%lf'
3303:
3304: @end example
3305:
3306: In this example the data are read from the file "MyData" using a more
3307: complicated format:
3308: @example
3309: plot 'MyData' using "%*lf%lf%*20[^\n]%lf"
3310:
3311: @end example
3312:
3313: The meaning of this format is:
3314:
3315: @example
3316: %*lf ignore a number
3317: %lf read a double-precision number (x by default)
3318: %*20[^\n] ignore 20 non-newline characters
3319: %lf read a double-precision number (y by default)
3320:
3321: @end example
3322:
3323: One trick is to use the ternary `?:` operator to filter data:
3324:
3325: @example
3326: plot 'file' using 1:($3>10 ? $2 : 1/0)
3327:
3328: @end example
3329:
3330: which plots the datum in column two against that in column one provided
3331: the datum in column three exceeds ten. `1/0` is undefined; `gnuplot`
3332: quietly ignores undefined points, so unsuitable points are suppressed.
3333:
3334: In fact, you can use a constant expression for the column number, provided it
3335: doesn't start with an opening parenthesis; constructs like `using
3336: 0+(complicated expression)` can be used. The crucial point is that the
3337: expression is evaluated once if it doesn't start with a left parenthesis, or
3338: once for each data point read if it does.
3339:
3340: If timeseries data are being used, the time can span multiple columns. The
3341: starting column should be specified. Note that the spaces within the time
3342: must be included when calculating starting columns for other data. E.g., if
3343: the first element on a line is a time with an embedded space, the y value
3344: should be specified as column three.
3345:
3346: It should be noted that `plot 'file'`, `plot 'file' using 1:2`, and `plot
3347: 'file' using ($1):($2)` can be subtly different: 1) if `file` has some lines
3348: with one column and some with two, the first will invent x values when they
3349: are missing, the second will quietly ignore the lines with one column, and
3350: the third will store an undefined value for lines with one point (so that in
3351: a plot with lines, no line joins points across the bad point); 2) if a line
3352: contains text at the first column, the first will abort the plot on an error,
3353: but the second and third should quietly skip the garbage.
3354:
3355: In fact, it is often possible to plot a file with lots of lines of garbage at
3356: the top simply by specifying
3357:
3358: @example
3359: plot 'file' using 1:2
3360:
3361: @end example
3362:
3363: However, if you want to leave text in your data files, it is safer to put the
3364: comment character (#) in the first column of the text lines.
3365: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/using.html,Feeble using demos. }
3366:
3367: @node errorbars, parametric, data-file, plot
3368: @subsection errorbars
3369:
3370: @c ?commands plot errorbars
3371: @c ?commands splot errorbars
3372: @c ?plot errorbars
3373: @c ?splot errorbars
3374: @cindex errorbars
3375:
3376: Error bars are supported for 2-d data file plots by reading one to four
3377: additional columns (or @ref{using} entries); these additional values are used in
3378: different ways by the various errorbar styles.
3379:
3380: In the default situation, `gnuplot` expects to see three, four, or six
3381: numbers on each line of the data file---either
3382:
3383: @example
3384: (x, y, ydelta),
3385: (x, y, ylow, yhigh),
3386: (x, y, xdelta),
3387: (x, y, xlow, xhigh),
3388: (x, y, xdelta, ydelta), or
3389: (x, y, xlow, xhigh, ylow, yhigh).
3390:
3391: @end example
3392:
3393: The x coordinate must be specified. The order of the numbers must be
3394: exactly as given above, though the @ref{using} qualifier can manipulate the order
3395: and provide values for missing columns. For example,
3396:
3397: @example
3398: plot 'file' with errorbars
3399: plot 'file' using 1:2:(sqrt($1)) with xerrorbars
3400: plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars
3401:
3402: @end example
3403:
3404: The last example is for a file containing an unsupported combination of
3405: relative x and absolute y errors. The @ref{using} entry generates absolute x min
3406: and max from the relative error.
3407:
3408: The y error bar is a vertical line plotted from (x, ylow) to (x, yhigh).
3409: If ydelta is specified instead of ylow and yhigh, ylow = y - ydelta and
3410: yhigh = y + ydelta are derived. If there are only two numbers on the record,
3411: yhigh and ylow are both set to y. The x error bar is a horizontal line
3412: computed in the same fashion. To get lines plotted between the data points,
3413: @ref{plot} the data file twice, once with errorbars and once with lines (but
3414: remember to use the `notitle` option on one to avoid two entries in the key).
3415:
3416: The error bars have crossbars at each end unless @ref{bar} is used (see @ref{bar} for details).
3417:
3418: If autoscaling is on, the ranges will be adjusted to include the error bars.
3419: @uref{http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html,Errorbar demos. }
3420:
3421: See @ref{using}, @ref{with}, and @ref{style} for more information.
3422:
3423: @node parametric, ranges, errorbars, plot
3424: @subsection parametric
3425:
3426: @c ?commands plot parametric
3427: @c ?commands splot parametric
3428: @c ?plot parametric
3429: @c ?splot parametric
3430: @cindex parametric
3431: @opindex parametric
3432:
3433:
3434: When in parametric mode (`set parametric`) mathematical expressions must be
3435: given in pairs for @ref{plot} and in triplets for `splot`.
3436:
3437: Examples:
3438: @example
3439: plot sin(t),t**2
3440: splot cos(u)*cos(v),cos(u)*sin(v),sin(u)
3441:
3442: @end example
3443:
3444: Data files are plotted as before, except any preceding parametric function
3445: must be fully specified before a data file is given as a plot. In other
3446: words, the x parametric function (`sin(t)` above) and the y parametric
3447: function (`t**2` above) must not be interrupted with any modifiers or data
3448: functions; doing so will generate a syntax error stating that the parametric
3449: function is not fully specified.
3450:
3451: Other modifiers, such as @ref{with} and `title`, may be specified only after the
3452: parametric function has been completed:
3453:
3454: @example
3455: plot sin(t),t**2 title 'Parametric example' with linespoints
3456: @end example
3457:
3458: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/param.html,Parametric Mode Demos. }
3459:
3460: @node ranges, title, parametric, plot
3461: @subsection ranges
3462:
3463: @c ?commands plot ranges
3464: @c ?commands splot ranges
3465: @c ?plot ranges
3466: @c ?splot ranges
3467: @cindex ranges
3468:
3469: The optional ranges specify the region of the graph that will be displayed.
3470:
3471: Syntax:
3472: @example
3473: [@{<dummy-var>=@}@{@{<min>@}:@{<max>@}@}]
3474: [@{@{<min>@}:@{<max>@}@}]
3475:
3476: @end example
3477:
3478: The first form applies to the independent variable (@ref{xrange} or @ref{trange}, if
3479: in parametric mode). The second form applies to the dependent variable
3480: @ref{yrange} (and @ref{xrange}, too, if in parametric mode). <dummy-var> is a new
3481: name for the independent variable. (The defaults may be changed with @ref{dummy}.) The optional <min> and <max> terms can be constant expressions or *.
3482:
3483: In non-parametric mode, the order in which ranges must be given is @ref{xrange}
3484: and @ref{yrange}.
3485:
3486: In parametric mode, the order for the @ref{plot} command is @ref{trange}, @ref{xrange},
3487: and @ref{yrange}. The following @ref{plot} command shows setting the @ref{trange} to
3488: [-pi:pi], the @ref{xrange} to [-1.3:1.3] and the @ref{yrange} to [-1:1] for the
3489: duration of the graph:
3490:
3491: @example
3492: plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2
3493:
3494: @end example
3495:
3496: Note that the x2range and y2range cannot be specified here---@ref{x2range}
3497: and @ref{y2range} must be used.
3498:
3499: Ranges are interpreted in the order listed above for the appropriate mode.
3500: Once all those needed are specified, no further ones must be listed, but
3501: unneeded ones cannot be skipped---use an empty range `[]` as a placeholder.
3502:
3503: `*` can be used to allow autoscaling of either of min and max. See also
3504: @ref{autoscale}.
3505:
3506: Ranges specified on the @ref{plot} or `splot` command line affect only that
3507: graph; use the @ref{xrange}, @ref{yrange}, etc., commands to change the
3508: default ranges for future graphs.
3509:
3510: With time data, you must provide the range (in the same manner as the time
3511: appears in the datafile) within quotes. `gnuplot` uses the @ref{timefmt} string
3512: to read the value---see @ref{timefmt}.
3513:
3514: Examples:
3515:
3516: This uses the current ranges:
3517: @example
3518: plot cos(x)
3519:
3520: @end example
3521:
3522: This sets the x range only:
3523: @example
3524: plot [-10:30] sin(pi*x)/(pi*x)
3525:
3526: @end example
3527:
3528: This is the same, but uses t as the dummy-variable:
3529: @example
3530: plot [t = -10 :30] sin(pi*t)/(pi*t)
3531:
3532: @end example
3533:
3534: This sets both the x and y ranges:
3535: @example
3536: plot [-pi:pi] [-3:3] tan(x), 1/x
3537:
3538: @end example
3539:
3540: This sets only the y range, and turns off autoscaling on both axes:
3541: @example
3542: plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)
3543:
3544: @end example
3545:
3546: This sets xmax and ymin only:
3547: @example
3548: plot [:200] [-pi:] exp(sin(x))
3549:
3550: @end example
3551:
3552: This sets the x range for a timeseries:
3553: @example
3554: set timefmt "%d/%m/%y %H:%M"
3555: plot ["1/6/93 12:00":"5/6/93 12:00"] 'timedata.dat'
3556:
3557: @end example
3558:
3559: @uref{http://www.nas.nasa.gov/~woo/gnuplot/ranges/ranges.html,See Demo. }
3560:
3561: @node title, with, ranges, plot
3562: @subsection title
3563:
3564: @c ?commands plot title
3565: @c ?commands splot title
3566: @c ?plot title
3567: @c ?splot title
3568: A line title for each function and data set appears in the key, accompanied
3569: by a sample of the line and/or symbol used to represent it. It can be
3570: changed by using the `title` option.
3571:
3572: Syntax:
3573: @example
3574: title "<title>" | notitle
3575:
3576: @end example
3577:
3578: where <title> is the new title of the line and must be enclosed in quotes.
3579: The quotes will not be shown in the key. A special character may be given as
3580: a backslash followed by its octal value ("\345"). The tab character "\t" is
3581: understood. Note that backslash processing occurs only for strings enclosed
3582: in double quotes---use single quotes to prevent such processing. The newline
3583: character "\n" is not processed in key entries in either type of string.
3584:
3585: The line title and sample can be omitted from the key by using the keyword
3586: `notitle`. A null title (`title ''`) is equivalent to `notitle`. If only
3587: the sample is wanted, use one or more blanks (`title ' '`).
3588:
3589: By default the line title is the function or file name as it appears on the
3590: @ref{plot} command. If it is a file name, any datafile modifiers specified will
3591: be included in the default title.
3592:
3593: The layout of the key itself (position, title justification, etc.) can be
3594: controlled by @ref{key}. Please see @ref{key} for details.
3595:
3596: Examples:
3597:
3598: This plots y=x with the title 'x':
3599: @example
3600: plot x
3601:
3602: @end example
3603:
3604: This plots x squared with title "x^2" and file "data.1" with title
3605: "measured data":
3606: @example
3607: plot x**2 title "x^2", 'data.1' t "measured data"
3608:
3609: @end example
3610:
3611: This puts an untitled circular border around a polar graph:
3612: @example
3613: set polar; plot my_function(t), 1 notitle
3614:
3615: @end example
3616:
3617: @node with, , title, plot
3618: @subsection with
3619:
3620: @c ?commands plot with
3621: @c ?commands splot with
3622: @c ?commands plot style
3623: @c ?commands splot style
3624: @c ?plot with
3625: @c ?plot style
3626: @c ?splot with
3627: @c ?splot style
3628: @cindex style
3629: @opindex style
3630:
3631:
3632: @cindex with
3633:
3634: Functions and data may be displayed in one of a large number of styles.
3635: The @ref{with} keyword provides the means of selection.
3636:
3637: Syntax:
3638: @example
3639: with <style> @{ @{linestyle | ls <line_style>@}
3640: | @{@{linetype | lt <line_type>@}
3641: @{linewidth | lw <line_width>@}
3642: @{pointtype | pt <point_type>@}
3643: @{pointsize | ps <point_size>@}@} @}
3644:
3645: @end example
3646:
3647: where <style> is either `lines`, `points`, @ref{linespoints}, @ref{impulses}, @ref{dots},
3648: @ref{steps}, @ref{fsteps}, @ref{histeps}, @ref{errorbars}, @ref{xerrorbars}, @ref{yerrorbars},
3649: @ref{xyerrorbars}, @ref{boxes}, @ref{boxerrorbars}, @ref{boxxyerrorbars}, @ref{financebars},
3650: @ref{candlesticks} or @ref{vector}. Some of these styles require additional
3651: information. See `set style <style>` for details of each style.
3652:
3653: Default styles are chosen with the @ref{style} and @ref{style}
3654: commands.
3655:
3656: By default, each function and data file will use a different line type and
3657: point type, up to the maximum number of available types. All terminal
3658: drivers support at least six different point types, and re-use them, in
3659: order, if more are required. The LaTeX driver supplies an additional six
3660: point types (all variants of a circle), and thus will only repeat after 12
3661: curves are plotted with points. The PostScript drivers (`postscript`)
3662: supplies a total of 64.
3663:
3664: If you wish to choose the line or point type for a single plot, <line_type>
3665: and <point_type> may be specified. These are positive integer constants (or
3666: expressions) that specify the line type and point type to be used for the
3667: plot. Use @ref{test} to display the types available for your terminal.
3668:
3669: You may also scale the line width and point size for a plot by using
3670: <line_width> and <point_size>, which are specified relative to the default
3671: values for each terminal. The pointsize may also be altered globally---see
3672: @ref{pointsize} for details. But note that both <point_size> as set here and
3673: as set by @ref{pointsize} multiply the default point size---their effects are
3674: not cumulative. That is, `set pointsize 2; plot x w p ps 3` will use points
3675: three times default size, not six.
3676:
3677: If you have defined specific line type/width and point type/size combinations
3678: with @ref{linestyle}, one of these may be selected by setting <line_style> to
3679: the index of the desired style.
3680:
3681: The keywords may be abbreviated as indicated.
3682:
3683: Note that the `linewidth` and @ref{pointsize} options are not supported by all
3684: terminals.
3685:
3686: Examples:
3687:
3688: This plots sin(x) with impulses:
3689: @example
3690: plot sin(x) with impulses
3691:
3692: @end example
3693:
3694: This plots x with points, x**2 with the default:
3695: @example
3696: plot x*y w points, x**2 + y**2
3697:
3698: @end example
3699:
3700: This plots tan(x) with the default function style, file "data.1" with lines:
3701: @example
3702: plot [ ] [-2:5] tan(x), 'data.1' with l
3703:
3704: @end example
3705:
3706: This plots "leastsq.dat" with impulses:
3707: @example
3708: plot 'leastsq.dat' w i
3709:
3710: @end example
3711:
3712: This plots the data file "population" with boxes:
3713: @example
3714: plot 'population' with boxes
3715:
3716: @end example
3717:
3718: This plots "exper.dat" with errorbars and lines connecting the points
3719: (errorbars require three or four columns):
3720: @example
3721: plot 'exper.dat' w lines, 'exper.dat' notitle w errorbars
3722:
3723: @end example
3724:
3725: This plots sin(x) and cos(x) with linespoints, using the same line type but
3726: different point types:
3727: @example
3728: plot sin(x) with linesp lt 1 pt 3, cos(x) with linesp lt 1 pt 4
3729:
3730: @end example
3731:
3732: This plots file "data" with points of type 3 and twice usual size:
3733: @example
3734: plot 'data' with points pointtype 3 pointsize 2
3735:
3736: @end example
3737:
3738: This plots two data sets with lines differing only by weight:
3739: @example
3740: plot 'd1' t "good" w l lt 2 lw 3, 'd2' t "bad" w l lt 2 lw 1
3741:
3742: @end example
3743:
3744: See @ref{style} to change the default styles.
3745: @uref{http://www.nas.nasa.gov/~woo/gnuplot/styles/styles.html,Styles demos. }
3746:
3747: @node print, pwd, plot, Commands
3748: @section print
3749:
3750: @c ?commands print
3751: @cindex print
3752: @cmindex print
3753:
3754:
3755: The @ref{print} command prints the value of <expression> to the screen. It is
3756: synonymous with `pause 0`. <expression> may be anything that `gnuplot` can
3757: evaluate that produces a number, or it can be a string.
3758:
3759: Syntax:
3760: @example
3761: print <expression> @{, <expression>, ...@}
3762:
3763: @end example
3764:
3765: See `expressions`.
3766:
3767: @node pwd, quit, print, Commands
3768: @section pwd
3769:
3770: @c ?commands pwd
3771: @cindex pwd
3772: @cmindex pwd
3773:
3774:
3775: The @ref{pwd} command prints the name of the working directory to the screen.
3776:
3777: @node quit, replot, pwd, Commands
3778: @section quit
3779:
3780: @c ?commands quit
3781: @cindex quit
3782: @cmindex quit
3783:
3784:
3785: The @ref{exit} and @ref{quit} commands and END-OF-FILE character will exit `gnuplot`.
3786: Each of these commands will clear the output device (as does the @ref{clear}
3787: command) before exiting.
3788:
3789: @node replot, reread, quit, Commands
3790: @section replot
3791:
3792: @c ?commands replot
3793: @cindex replot
3794: @cmindex replot
3795:
3796:
3797: The @ref{replot} command without arguments repeats the last @ref{plot} or `splot`
3798: command. This can be useful for viewing a plot with different `set` options,
3799: or when generating the same plot for several devices.
3800:
3801: Arguments specified after a @ref{replot} command will be added onto the last
3802: @ref{plot} or `splot` command (with an implied ',' separator) before it is
3803: repeated. @ref{replot} accepts the same arguments as the @ref{plot} and `splot`
3804: commands except that ranges cannot be specified. Thus you can use @ref{replot}
3805: to plot a function against the second axes if the previous command was @ref{plot}
3806: but not if it was `splot`, and similarly you can use @ref{replot} to add a plot
3807: from a binary file only if the previous command was `splot`.
3808:
3809: N.B.---use of
3810:
3811: @example
3812: plot '-' ; ... ; replot
3813:
3814: @end example
3815:
3816: is not recommended. `gnuplot` does not store the inline data internally, so
3817: since @ref{replot} appends new information to the previous @ref{plot} and then
3818: executes the modified command, the `'-'` from the initial @ref{plot} will expect
3819: to read inline data again.
3820:
3821: Note that @ref{replot} does not work in @ref{multiplot} mode, since it reproduces
3822: only the last plot rather than the entire screen.
3823:
3824: See also `command-line-editing` for ways to edit the last @ref{plot} (`splot`)
3825: command.
3826:
3827: @node reread, reset, replot, Commands
3828: @section reread
3829:
3830: @c ?commands reread
3831: @cindex reread
3832: @cmindex reread
3833:
3834:
3835: The @ref{reread} command causes the current `gnuplot` command file, as specified
3836: by a @ref{load} command or on the command line, to be reset to its starting
3837: point before further commands are read from it. This essentially implements
3838: an endless loop of the commands from the beginning of the command file to
3839: the @ref{reread} command. (But this is not necessarily a disaster---@ref{reread} can
3840: be very useful when used in conjunction with @ref{if}. See @ref{if} for details.)
3841: The @ref{reread} command has no effect if input from standard input.
3842:
3843: Examples:
3844:
3845: Suppose the file "looper" contains the commands
3846: @example
3847: a=a+1
3848: plot sin(x*a)
3849: pause -1
3850: if(a<5) reread
3851: @end example
3852:
3853: and from within `gnuplot` you submit the commands
3854: @example
3855: a=0
3856: load 'looper'
3857: @end example
3858:
3859: The result will be four plots (separated by the @ref{pause} message).
3860:
3861: Suppose the file "data" contains six columns of numbers with a total yrange
3862: from 0 to 10; the first is x and the next are five different functions of x.
3863: Suppose also that the file "plotter" contains the commands
3864: @example
3865: c_p = c_p+1
3866: plot "$0" using 1:c_p with lines linetype c_p
3867: if(c_p < n_p) reread
3868: @end example
3869:
3870: and from within `gnuplot` you submit the commands
3871: @example
3872: n_p=6
3873: c_p=1
3874: set nokey
3875: set yrange [0:10]
3876: set multiplot
3877: call 'plotter' 'data'
3878: set nomultiplot
3879: @end example
3880:
3881: The result is a single graph consisting of five plots. The yrange must be
3882: set explicitly to guarantee that the five separate graphs (drawn on top of
3883: each other in multiplot mode) will have exactly the same axes. The linetype
3884: must be specified; otherwise all the plots would be drawn with the same type.
3885: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/animate.html,Reread Animation Demo}
3886:
3887: @node reset, save, reread, Commands
3888: @section reset
3889:
3890: @c ?commands reset
3891: @cindex reset
3892: @cmindex reset
3893:
3894:
3895: The @ref{reset} command causes all options that can be set with the `set`
3896: command to take on their default values. The only exceptions are that the
3897: terminal set with `set term` and the output file set with @ref{output} are
3898: left unchanged. This command is useful, e.g., to restore the default
3899: settings at the end of a command file, or to return to a defined state after
3900: lots of settings have been changed within a command file. Please refer to
3901: the `set` command to see the default values that the various options take.
3902:
3903: @node save, set-show, reset, Commands
3904: @section save
3905:
3906: @c ?commands save
3907: @cindex save
3908: @cmindex save
3909:
3910:
3911: The @ref{save} command saves user-defined functions, variables, `set` options,
3912: or all three, plus the last @ref{plot} (`splot`) command to the specified file.
3913:
3914: Syntax:
3915: @example
3916: save @{<option>@} '<filename>'
3917:
3918: @end example
3919:
3920: where <option> is @ref{functions}, @ref{variables} or `set`. If no option is used,
3921: `gnuplot` saves functions, variables, `set` options and the last @ref{plot}
3922: (`splot`) command.
3923:
3924: @ref{save}d files are written in text format and may be read by the @ref{load}
3925: command.
3926:
3927: The filename must be enclosed in quotes.
3928:
3929: Examples:
3930: @example
3931: save 'work.gnu'
3932: save functions 'func.dat'
3933: save var 'var.dat'
3934: save set 'options.dat'
3935:
3936: @end example
3937:
3938: @node set-show, shell, save, Commands
3939: @section set-show
3940:
3941: @c ?commands set
3942: @c ?commands show
3943: @cindex set
3944:
3945: @cindex show
3946:
3947: @c ?show all
3948: The `set` command can be used to sets _lots_ of options. No screen is
3949: drawn, however, until a @ref{plot}, `splot`, or @ref{replot} command is given.
3950:
3951: The `show` command shows their settings; `show all` shows all the
3952: settings.
3953:
3954: If a variable contains time/date data, `show` will display it according to
3955: the format currently defined by @ref{timefmt}, even if that was not in effect
3956: when the variable was initially defined.
3957:
3958: @menu
3959: * angles::
3960: * arrow::
3961: * autoscale::
3962: * bar::
3963: * bmargin::
3964: * border::
3965: * boxwidth::
3966: * clabel::
3967: * clip::
3968: * cntrparam::
3969: * contour::
3970: * data_style::
3971: * dgrid3d::
3972: * dummy::
3973: * encoding::
3974: * format::
3975: * function_style::
3976: * functions::
3977: * grid::
3978: * hidden3d::
3979: * isosamples::
3980: * key::
3981: * label::
3982: * linestyle::
3983: * lmargin::
3984: * locale::
3985: * logscale::
3986: * mapping::
3987: * margin::
3988: * missing::
3989: * multiplot::
3990: * mx2tics::
3991: * mxtics::
3992: * my2tics::
3993: * mytics::
3994: * mztics::
3995: * offsets::
3996: * origin::
3997: * output::
3998: * parametric_::
3999: * pointsize::
4000: * polar::
4001: * rmargin::
4002: * rrange::
4003: * samples::
4004: * size::
4005: * style::
4006: * surface::
4007: * terminal::
4008: * tics::
4009: * ticslevel::
4010: * ticscale::
4011: * timestamp::
4012: * timefmt::
4013: * title_::
4014: * tmargin::
4015: * trange::
4016: * urange::
4017: * variables::
4018: * version::
4019: * view::
4020: * vrange::
4021: * x2data::
4022: * x2dtics::
4023: * x2label::
4024: * x2mtics::
4025: * x2range::
4026: * x2tics::
4027: * x2zeroaxis::
4028: * xdata::
4029: * xdtics::
4030: * xlabel::
4031: * xmtics::
4032: * xrange::
4033: * xtics::
4034: * xzeroaxis::
4035: * y2data::
4036: * y2dtics::
4037: * y2label::
4038: * y2mtics::
4039: * y2range::
4040: * y2tics::
4041: * y2zeroaxis::
4042: * ydata::
4043: * ydtics::
4044: * ylabel::
4045: * ymtics::
4046: * yrange::
4047: * ytics::
4048: * yzeroaxis::
4049: * zdata::
4050: * zdtics::
4051: * zero::
4052: * zeroaxis::
4053: * zlabel::
4054: * zmtics::
4055: * zrange::
4056: * ztics::
4057: @end menu
4058:
4059: @node angles, arrow, set-show, set-show
4060: @subsection angles
4061:
4062: @c ?commands set angles
4063: @c ?commands show angles
4064: @c ?set angles
4065: @c ?show angles
4066: @cindex angles
4067: @opindex angles
4068:
4069:
4070: @c ?commands set angles degrees
4071: @c ?set angles degrees
4072: @c ?angles degrees
4073: @cindex degrees
4074:
4075: By default, `gnuplot` assumes the independent variable in polar graphs is in
4076: units of radians. If `set angles degrees` is specified before `set polar`,
4077: then the default range is [0:360] and the independent variable has units of
4078: degrees. This is particularly useful for plots of data files. The angle
4079: setting also applies to 3-d mapping as set via the @ref{mapping} command.
4080:
4081: Syntax:
4082: @example
4083: set angles @{degrees | radians@}
4084: show angles
4085:
4086: @end example
4087:
4088: The angle specified in `set grid polar` is also read and displayed in the
4089: units specified by @ref{angles}.
4090:
4091: @ref{angles} also affects the arguments of the machine-defined functions
4092: sin(x), cos(x) and tan(x), and the outputs of asin(x), acos(x), atan(x),
4093: atan2(x), and arg(x). It has no effect on the arguments of hyperbolic
4094: functions or Bessel functions. However, the output arguments of inverse
4095: hyperbolic functions of complex arguments are affected; if these functions
4096: are used, `set angles radians` must be in effect to maintain consistency
4097: between input and output arguments.
4098:
4099: @example
4100: x=@{1.0,0.1@}
4101: set angles radians
4102: y=sinh(x)
4103: print y #prints @{1.16933, 0.154051@}
4104: print asinh(y) #prints @{1.0, 0.1@}
4105: @end example
4106:
4107: but
4108: @example
4109: set angles degrees
4110: y=sinh(x)
4111: print y #prints @{1.16933, 0.154051@}
4112: print asinh(y) #prints @{57.29578, 5.729578@}
4113: @end example
4114:
4115: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/poldat.html,Polar plot using @ref{angles}. }
4116:
4117: @node arrow, autoscale, angles, set-show
4118: @subsection arrow
4119:
4120: @c ?commands set arrow
4121: @c ?commands set noarrow
4122: @c ?commands show arrow
4123: @c ?set arrow
4124: @c ?set noarrow
4125: @c ?show arrow
4126: @cindex arrow
4127: @opindex arrow
4128:
4129:
4130: @cindex noarrow
4131:
4132: Arbitrary arrows can be placed on a plot using the @ref{arrow} command.
4133:
4134: Syntax:
4135: @example
4136: set arrow @{<tag>@} @{from <position>@} @{to <position>@} @{@{no@}head@}
4137: @{ @{linestyle | ls <line_style>@}
4138: | @{linetype | lt <line_type>@}
4139: @{linewidth | lw <line_width@} @}
4140: set noarrow @{<tag>@}
4141: show arrow
4142:
4143: @end example
4144:
4145: <tag> is an integer that identifies the arrow. If no tag is given, the
4146: lowest unused tag value is assigned automatically. The tag can be used to
4147: delete or change a specific arrow. To change any attribute of an existing
4148: arrow, use the @ref{arrow} command with the appropriate tag and specify the
4149: parts of the arrow to be changed.
4150:
4151: The <position>s are specified by either x,y or x,y,z, and may be preceded by
4152: `first`, `second`, `graph`, or `screen` to select the coordinate system.
4153: Unspecified coordinates default to 0. The endpoints can be specified in
4154: one of four coordinate systems---`first` or `second` axes, `graph` or
4155: `screen`. See `coordinates` for details. A coordinate system specifier
4156: does not carry over from the "from" position to the "to" position. Arrows
4157: outside the screen boundaries are permitted but may cause device errors.
4158:
4159: Specifying `nohead` produces an arrow drawn without a head---a line segment.
4160: This gives you yet another way to draw a line segment on the plot. By
4161: default, arrows have heads.
4162:
4163: The line style may be selected from a user-defined list of line styles (see
4164: @ref{linestyle}) or may be defined here by providing values for <line_type>
4165: (an index from the default list of styles) and/or <line_width> (which is a
4166: multiplier for the default width).
4167:
4168: Note, however, that if a user-defined line style has been selected, its
4169: properties (type and width) cannot be altered merely by issuing another
4170: @ref{arrow} command with the appropriate index and `lt` or `lw`.
4171:
4172: Examples:
4173:
4174: To set an arrow pointing from the origin to (1,2) with user-defined style 5,
4175: use:
4176: @example
4177: set arrow to 1,2 ls 5
4178:
4179: @end example
4180:
4181: To set an arrow from bottom left of plotting area to (-5,5,3), and tag the
4182: arrow number 3, use:
4183: @example
4184: set arrow 3 from graph 0,0 to -5,5,3
4185:
4186: @end example
4187:
4188: To change the preceding arrow to end at 1,1,1, without an arrow head and
4189: double its width, use:
4190: @example
4191: set arrow 3 to 1,1,1 nohead lw 2
4192:
4193: @end example
4194:
4195: To draw a vertical line from the bottom to the top of the graph at x=3, use:
4196: @example
4197: set arrow from 3, graph 0 to 3, graph 1 nohead
4198:
4199: @end example
4200:
4201: To delete arrow number 2, use:
4202: @example
4203: set noarrow 2
4204:
4205: @end example
4206:
4207: To delete all arrows, use:
4208: @example
4209: set noarrow
4210:
4211: @end example
4212:
4213: To show all arrows (in tag order), use:
4214: @example
4215: show arrow
4216: @end example
4217:
4218: @uref{http://www.nas.nasa.gov/~woo/gnuplot/arrows/arrows.html,Arrows Demos. }
4219:
4220: @node autoscale, bar, arrow, set-show
4221: @subsection autoscale
4222:
4223: @c ?commands set autoscale
4224: @c ?commands set noautoscale
4225: @c ?commands show autoscale
4226: @c ?set autoscale
4227: @c ?set noautoscale
4228: @c ?show autoscale
4229: @cindex autoscale
4230: @opindex autoscale
4231:
4232:
4233: @cindex noautoscale
4234:
4235: Autoscaling may be set individually on the x, y or z axis or globally on all
4236: axes. The default is to autoscale all axes.
4237:
4238: Syntax:
4239: @example
4240: set autoscale @{<axes>@{min|max@}@}
4241: set noautoscale @{<axes>@{min|max@}@}
4242: show autoscale
4243:
4244: @end example
4245:
4246: where <axes> is either `x`, `y`, `z`, `x2`, `y2` or `xy`. A keyword with
4247: `min` or `max` appended (this cannot be done with `xy`) tells `gnuplot` to
4248: autoscale just the minimum or maximum of that axis. If no keyword is given,
4249: all axes are autoscaled.
4250:
4251: When autoscaling, the axis range is automatically computed and the dependent
4252: axis (y for a @ref{plot} and z for `splot`) is scaled to include the range of the
4253: function or data being plotted.
4254:
4255: If autoscaling of the dependent axis (y or z) is not set, the current y or z
4256: range is used.
4257:
4258: Autoscaling the independent variables (x for @ref{plot} and x,y for `splot`) is a
4259: request to set the domain to match any data file being plotted. If there are
4260: no data files, autoscaling an independent variable has no effect. In other
4261: words, in the absence of a data file, functions alone do not affect the x
4262: range (or the y range if plotting z = f(x,y)).
4263:
4264: Please see @ref{xrange} for additional information about ranges.
4265:
4266: The behavior of autoscaling remains consistent in parametric mode, (see `set
4267: parametric`). However, there are more dependent variables and hence more
4268: control over x, y, and z axis scales. In parametric mode, the independent or
4269: dummy variable is t for @ref{plot}s and u,v for `splot`s. @ref{autoscale} in
4270: parametric mode, then, controls all ranges (t, u, v, x, y, and z) and allows
4271: x, y, and z to be fully autoscaled.
4272:
4273: Autoscaling works the same way for polar mode as it does for parametric mode
4274: for @ref{plot}, with the extension that in polar mode @ref{dummy} can be used to
4275: change the independent variable from t (see @ref{dummy}).
4276:
4277: When tics are displayed on second axes but no plot has been specified for
4278: those axes, x2range and y2range are inherited from xrange and yrange. This
4279: is done _before_ xrange and yrange are autoextended to a whole number of
4280: tics, which can cause unexpected results.
4281:
4282: Examples:
4283:
4284: This sets autoscaling of the y axis (other axes are not affected):
4285: @example
4286: set autoscale y
4287:
4288: @end example
4289:
4290: This sets autoscaling only for the minimum of the y axis (the maximum of the
4291: y axis and the other axes are not affected):
4292: @example
4293: set autoscale ymin
4294:
4295: @end example
4296:
4297: This sets autoscaling of the x and y axes:
4298: @example
4299: set autoscale xy
4300:
4301: @end example
4302:
4303: This sets autoscaling of the x, y, z, x2 and y2 axes:
4304: @example
4305: set autoscale
4306:
4307: @end example
4308:
4309: This disables autoscaling of the x, y, z, x2 and y2 axes:
4310: @example
4311: set noautoscale
4312:
4313: @end example
4314:
4315: This disables autoscaling of the z axis only:
4316: @example
4317: set noautoscale z
4318:
4319: @end example
4320:
4321: @menu
4322: * parametric_mode::
4323: * polar_mode::
4324: @end menu
4325:
4326: @node parametric_mode, polar_mode, autoscale, autoscale
4327: @subsubsection parametric mode
4328:
4329: @c ?commands set autoscale parametric
4330: @c ?set autoscale parametric
4331: @c ?set autoscale t
4332: When in parametric mode (`set parametric`), the xrange is as fully scalable
4333: as the y range. In other words, in parametric mode the x axis can be
4334: automatically scaled to fit the range of the parametric function that is
4335: being plotted. Of course, the y axis can also be automatically scaled just
4336: as in the non-parametric case. If autoscaling on the x axis is not set, the
4337: current x range is used.
4338:
4339: Data files are plotted the same in parametric and non-parametric mode.
4340: However, there is a difference in mixed function and data plots: in
4341: non-parametric mode with autoscaled x, the x range of the datafile controls
4342: the x range of the functions; in parametric mode it has no influence.
4343:
4344: For completeness a last command `set autoscale t` is accepted. However, the
4345: effect of this "scaling" is very minor. When `gnuplot` determines that the
4346: t range would be empty, it makes a small adjustment if autoscaling is true.
4347: Otherwise, `gnuplot` gives an error. Such behavior may, in fact, not be very
4348: useful and the command `set autoscale t` is certainly questionable.
4349:
4350: `splot` extends the above ideas as you would expect. If autoscaling is set,
4351: then x, y, and z ranges are computed and each axis scaled to fit the
4352: resulting data.
4353:
4354: @node polar_mode, , parametric_mode, autoscale
4355: @subsubsection polar mode
4356:
4357: @c ?commands set autoscale polar
4358: @c ?set autoscale polar
4359: @c ?set autoscale t
4360: When in polar mode (`set polar`), the xrange and the yrange are both found
4361: from the polar coordinates, and thus they can both be automatically scaled.
4362: In other words, in polar mode both the x and y axes can be automatically
4363: scaled to fit the ranges of the polar function that is being plotted.
4364:
4365: When plotting functions in polar mode, the rrange may be autoscaled. When
4366: plotting data files in polar mode, the trange may also be autoscaled. Note
4367: that if the trange is contained within one quadrant, autoscaling will produce
4368: a polar plot of only that single quadrant.
4369:
4370: Explicitly setting one or two ranges but not others may lead to unexpected
4371: results.
4372: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/poldat.html,See polar demos }
4373:
4374: @node bar, bmargin, autoscale, set-show
4375: @subsection bar
4376:
4377: @c ?commands set bar
4378: @c ?commands show bar
4379: @c ?set bar
4380: @c ?show bar
4381: The @ref{bar} command controls the tics at the ends of errorbars.
4382:
4383: Syntax:
4384: @example
4385: set bar @{small | large | <size>@}
4386: show bar
4387:
4388: @end example
4389:
4390: `small` is a synonym for 0.0, and `large` for 1.0.
4391: The default is 1.0 if no size is given.
4392:
4393: @node bmargin, border, bar, set-show
4394: @subsection bmargin
4395:
4396: @c ?commands set bmargin
4397: @c ?set bmargin
4398: @cindex bmargin
4399: @opindex bmargin
4400:
4401:
4402: The command @ref{bmargin} sets the size of the bottom margin. Please see
4403: @ref{margin} for details.
4404:
4405: @node border, boxwidth, bmargin, set-show
4406: @subsection border
4407:
4408: @c ?commands set border
4409: @c ?commands set noborder
4410: @c ?commands show border
4411: @c ?set border
4412: @c ?set noborder
4413: @c ?show border
4414: @cindex border
4415: @opindex border
4416:
4417:
4418: @cindex noborder
4419:
4420: The @ref{border} and `set noborder` commands control the display of the graph
4421: borders for the @ref{plot} and `splot` commands.
4422:
4423: Syntax:
4424: @example
4425: set border @{<integer> @{ @{linestyle | ls <line_style>@}
4426: | @{linetype | lt <line_type> @}
4427: @{linewidth | lw <line_width>@} @} @}
4428: set noborder
4429: show border
4430:
4431: @end example
4432:
4433: The borders are encoded in a 12-bit integer: the bottom four bits control the
4434: border for @ref{plot} and the sides of the base for `splot`; The next four bits
4435: control the verticals in `splot`; the top four bits control the edges on top
4436: of the `splot`. In detail, the `<integer>` should be the sum of the
4437: appropriate entries from the following table:
4438:
4439:
4440: @example
4441: plot border splot splot
4442: Side splot base verticals top
4443: bottom (south) 1 16 256
4444: left (west) 2 32 512
4445: top (north) 4 64 1024
4446: right (east) 8 128 2048
4447:
4448: @end example
4449:
4450:
4451: The default is 31, which is all four sides for @ref{plot}, and base and z axis
4452: for `splot`.
4453:
4454: Using the optional <line_style>, <line_type> and <line_width>
4455: specifiers, the way the border lines are drawn can be influenced
4456: (limited by what the current terminal driver supports). By default,
4457: the border is drawn with twice the usual linewidth. The <line_width>
4458: specifier scales this default value; for example, `set border 15 lw 2`
4459: will produce a border with four times the usual linewidth.
4460:
4461: Various axes or combinations of axes may be added together in the command.
4462:
4463: To have tics on edges other than bottom and left, disable the usual tics and
4464: enable the second axes.
4465:
4466: Examples:
4467:
4468: Draw all borders:
4469: @example
4470: set border
4471:
4472: @end example
4473:
4474: Draw only the SOUTHWEST borders:
4475: @example
4476: set border 3
4477:
4478: @end example
4479:
4480: Draw a complete box around a `splot`:
4481: @example
4482: set border 4095
4483:
4484: @end example
4485:
4486: Draw a partial box, omitting the front vertical:
4487: @example
4488: set border 127+256+512
4489:
4490: @end example
4491:
4492: Draw only the NORTHEAST borders:
4493: @example
4494: set noxtics; set noytics; set x2tics; set y2tics; set border 12
4495:
4496: @end example
4497:
4498: @uref{http://www.nas.nasa.gov/~woo/gnuplot/borders/borders.html,Borders Demo. }
4499:
4500: @node boxwidth, clabel, border, set-show
4501: @subsection boxwidth
4502:
4503: @c ?commands set boxwidth
4504: @c ?commands show boxwidth
4505: @c ?set boxwidth
4506: @c ?show boxwidth
4507: @cindex boxwidth
4508: @opindex boxwidth
4509:
4510:
4511: The @ref{boxwidth} command is used to set the default width of boxes in the
4512: @ref{boxes} and @ref{boxerrorbars} styles.
4513:
4514: Syntax:
4515: @example
4516: set boxwidth @{<width>@}
4517: show boxwidth
4518:
4519: @end example
4520:
4521: If a data file is plotted without the width being specified in the third,
4522: fourth, or fifth column (or @ref{using} entry), or if a function is plotted, the
4523: width of each box is set by the @ref{boxwidth} command. (If a width is given
4524: both in the file and by the @ref{boxwidth} command, the one in the file is
4525: used.) If the width is not specified in one of these ways, the width of each
4526: box will be calculated automatically so that it touches the adjacent boxes.
4527: In a four-column data set, the fourth column will be interpreted as the box
4528: width unless the width is set to -2.0, in which case the width will be
4529: calculated automatically. See @ref{boxerrorbars} for more details.
4530:
4531: To set the box width to automatic use the command
4532: @example
4533: set boxwidth
4534: @end example
4535:
4536: or, for four-column data,
4537: @example
4538: set boxwidth -2
4539:
4540: @end example
4541:
4542: The same effect can be achieved with the @ref{using} keyword in @ref{plot}:
4543: @example
4544: plot 'file' using 1:2:3:4:(-2)
4545:
4546: @end example
4547:
4548: @node clabel, clip, boxwidth, set-show
4549: @subsection clabel
4550:
4551: @c ?commands set clabel
4552: @c ?commands set noclabel
4553: @c ?commands show clabel
4554: @c ?set clabel
4555: @c ?set noclabel
4556: @c ?show clabel
4557: @cindex clabel
4558: @opindex clabel
4559:
4560:
4561: @cindex noclabel
4562:
4563: `gnuplot` will vary the linetype used for each contour level when clabel is
4564: set. When this option on (the default), a legend labels each linestyle with
4565: the z level it represents. It is not possible at present to separate the
4566: contour labels from the surface key.
4567:
4568: Syntax:
4569: @example
4570: set clabel @{'<format>'@}
4571: set noclabel
4572: show clabel
4573:
4574: @end example
4575:
4576: The default for the format string is %8.3g, which gives three decimal places.
4577: This may produce poor label alignment if the key is altered from its default
4578: configuration.
4579:
4580: The first contour linetype, or only contour linetype when clabel is off, is
4581: the surface linetype +1; contour points are the same style as surface points.
4582:
4583: See also @ref{contour}.
4584:
4585: @node clip, cntrparam, clabel, set-show
4586: @subsection clip
4587:
4588: @c ?commands set clip
4589: @c ?commands set noclip
4590: @c ?commands show clip
4591: @c ?set clip
4592: @c ?set noclip
4593: @c ?show clip
4594: @cindex clip
4595: @opindex clip
4596:
4597:
4598: @cindex noclip
4599:
4600: `gnuplot` can clip data points and lines that are near the boundaries of a
4601: graph.
4602:
4603: Syntax:
4604: @example
4605: set clip <clip-type>
4606: set noclip <clip-type>
4607: show clip
4608:
4609: @end example
4610:
4611: Three clip types are supported by `gnuplot`: `points`, `one`, and `two`.
4612: One, two, or all three clip types may be active for a single graph.
4613:
4614: The `points` clip type forces `gnuplot` to clip (actually, not plot at all)
4615: data points that fall within but too close to the boundaries. This is done
4616: so that large symbols used for points will not extend outside the boundary
4617: lines. Without clipping points near the boundaries, the plot may look bad.
4618: Adjusting the x and y ranges may give similar results.
4619:
4620: Setting the `one` clip type causes `gnuplot` to draw a line segment which has
4621: only one of its two endpoints within the graph. Only the in-range portion of
4622: the line is drawn. The alternative is to not draw any portion of the line
4623: segment.
4624:
4625: Some lines may have both endpoints out of range, but pass through the graph.
4626: Setting the `two` clip-type allows the visible portion of these lines to be
4627: drawn.
4628:
4629: In no case is a line drawn outside the graph.
4630:
4631: The defaults are `noclip points`, `clip one`, and `noclip two`.
4632:
4633: To check the state of all forms of clipping, use
4634: @example
4635: show clip
4636:
4637: @end example
4638:
4639: For backward compatibility with older versions, the following forms are also
4640: permitted:
4641: @example
4642: set clip
4643: set noclip
4644:
4645: @end example
4646:
4647: @ref{clip} is synonymous with `set clip points`; `set noclip` turns off all
4648: three types of clipping.
4649:
4650: @node cntrparam, contour, clip, set-show
4651: @subsection cntrparam
4652:
4653: @c ?commands set cntrparam
4654: @c ?commands show cntrparam
4655: @c ?set cntrparam
4656: @c ?show cntrparam
4657: @cindex cntrparam
4658: @opindex cntrparam
4659:
4660:
4661: @ref{cntrparam} controls the generation of contours and their smoothness for
4662: a contour plot. @ref{contour} displays current settings of @ref{cntrparam} as
4663: well as @ref{contour}.
4664:
4665: Syntax:
4666: @example
4667: set cntrparam @{ @{linear | cubicspline | bspline@}
4668: @{ points <n>@} @{ order <n> @}
4669: @{ levels auto @{<n>@} | <n>
4670: | discrete <z1> @{,<z2>@{,<z3>...@}@}
4671: | incremental <start>, <incr> @{,<end>@}
4672: @}
4673: @}
4674: show contour
4675:
4676: @end example
4677:
4678: This command has two functions. First, it sets the values of z for which
4679: contour points are to be determined (by linear interpolation between data
4680: points or function isosamples.) Second, it controls the way contours are
4681: drawn between the points determined to be of equal z. <n> should be an
4682: integral constant expression and <z1>, <z2> ... any constant expressions.
4683: The parameters are:
4684:
4685: `linear`, `cubicspline`, `bspline`---Controls type of approximation or
4686: interpolation. If `linear`, then straight line segments connect points of
4687: equal z magnitude. If `cubicspline`, then piecewise-linear contours are
4688: interpolated between the same equal z points to form somewhat smoother
4689: contours, but which may undulate. If `bspline`, a guaranteed-smoother curve
4690: is drawn, which only approximates the position of the points of equal-z.
4691:
4692: `points`---Eventually all drawings are done with piecewise-linear strokes.
4693: This number controls the number of line segments used to approximate the
4694: `bspline` or `cubicspline` curve. Number of cubicspline or bspline
4695: segments (strokes) = `points` * number of linear segments.
4696:
4697: `order`---Order of the bspline approximation to be used. The bigger this
4698: order is, the smoother the resulting contour. (Of course, higher order
4699: bspline curves will move further away from the original piecewise linear
4700: data.) This option is relevant for `bspline` mode only. Allowed values are
4701: integers in the range from 2 (linear) to 10.
4702:
4703: `levels`--- Selection of contour levels, controlled by `auto` (default),
4704: `discrete`, `incremental`, and <n>, number of contour levels, limited to
4705: @example
4706: MAX_DISCRETE_LEVELS as defined in plot.h (30 is standard.)
4707:
4708: @end example
4709:
4710: For `auto`, <n> specifies a nominal number of levels; the actual number will
4711: be adjusted to give simple labels. If the surface is bounded by zmin and zmax,
4712: contours will be generated at integer multiples of dz between zmin and zmax,
4713: where dz is 1, 2, or 5 times some power of ten (like the step between two
4714: tic marks).
4715:
4716: For `levels discrete`, contours will be generated at z = <z1>, <z2> ... as
4717: specified; the number of discrete levels sets the number of contour levels.
4718: In `discrete` mode, any `set cntrparms levels <n>` are ignored.
4719:
4720: For `incremental`, contours are generated at values of z beginning at <start>
4721: and increasing by <increment>, until the number of contours is reached. <end>
4722: is used to determine the number of contour levels, which will be changed by
4723: any subsequent `set cntrparam levels <n>`.
4724:
4725: If the command @ref{cntrparam} is given without any arguments specified, the
4726: defaults are used: linear, 5 points, order 4, 5 auto levels.
4727:
4728: Examples:
4729: @example
4730: set cntrparam bspline
4731: set cntrparam points 7
4732: set cntrparam order 10
4733:
4734: @end example
4735:
4736: To select levels automatically, 5 if the level increment criteria are met:
4737: @example
4738: set cntrparam levels auto 5
4739:
4740: @end example
4741:
4742: To specify discrete levels at .1, .37, and .9:
4743: @example
4744: set cntrparam levels discrete .1,1/exp(1),.9
4745:
4746: @end example
4747:
4748: To specify levels from 0 to 4 with increment 1:
4749: @example
4750: set cntrparam levels incremental 0,1,4
4751:
4752: @end example
4753:
4754: To set the number of levels to 10 (changing an incremental end or possibly
4755: the number of auto levels):
4756: @example
4757: set cntrparam levels 10
4758:
4759: @end example
4760:
4761: To set the start and increment while retaining the number of levels:
4762: @example
4763: set cntrparam levels incremental 100,50
4764:
4765: @end example
4766:
4767: See also @ref{contour} for control of where the contours are drawn, and @ref{clabel} for control of the format of the contour labels and linetypes.
4768: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/contours.html,Contours Demo} and
4769: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/discrete.html,contours with User Defined Levels.}
4770:
4771: @node contour, data_style, cntrparam, set-show
4772: @subsection contour
4773:
4774: @c ?commands set contour
4775: @c ?commands set nocontour
4776: @c ?commands show contour
4777: @c ?set contour
4778: @c ?set nocontour
4779: @c ?show contour
4780: @cindex contour
4781: @opindex contour
4782:
4783:
4784: @cindex nocontour
4785:
4786: @ref{contour} enables contour drawing for surfaces. This option is available
4787: for `splot` only.
4788:
4789: Syntax:
4790: @example
4791: set contour @{base | surface | both@}
4792: set nocontour
4793: show contour
4794:
4795: @end example
4796:
4797: The three options specify where to draw the contours: `base` draws the
4798: contours on the grid base where the x/ytics are placed, @ref{surface} draws the
4799: contours on the surfaces themselves, and `both` draws the contours on both
4800: the base and the surface. If no option is provided, the default is `base`.
4801:
4802: See also @ref{cntrparam} for the parameters that affect the drawing of
4803: contours, and @ref{clabel} for control of labelling of the contours.
4804:
4805: The surface can be switched off (see @ref{surface}), giving a contour-only
4806: graph. Though it is possible to use @ref{size} to enlarge the plot to fill
4807: the screen, more control over the output format can be obtained by writing
4808: the contour information to a file, and rereading it as a 2-d datafile plot:
4809:
4810: @example
4811: set nosurface
4812: set contour
4813: set cntrparam ...
4814: set term table
4815: set out 'filename'
4816: splot ...
4817: set out
4818: # contour info now in filename
4819: set term <whatever>
4820: plot 'filename'
4821:
4822: @end example
4823:
4824: In order to draw contours, the data should be organized as "grid data". In
4825: such a file all the points for a single y-isoline are listed, then all the
4826: points for the next y-isoline, and so on. A single blank line (a line
4827: containing no characters other than blank spaces and a carriage return and/or
4828: a line feed) separates one y-isoline from the next. See also `splot datafile`.
4829:
4830: If contours are desired from non-grid data, @ref{dgrid3d} can be used to
4831: create an appropriate grid. See @ref{dgrid3d} for more information.
4832: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/contours.html,Contours Demo} and
4833: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/discrete.html,contours with User Defined Levels.}
4834:
4835: @node data_style, dgrid3d, contour, set-show
4836: @subsection data style
4837:
4838: @c ?commands set data style
4839: @c ?commands show data style
4840: @c ?set data style
4841: @c ?show data style
4842: @c ?data style
4843: The @ref{style} command changes the default plotting style for data
4844: plots.
4845:
4846: Syntax:
4847: @example
4848: set data style <style-choice>
4849: show data style
4850:
4851: @end example
4852:
4853: See @ref{style} for the choices. If no choice is given, the choices are
4854: listed. @ref{style} shows the current default data plotting style.
4855:
4856: @node dgrid3d, dummy, data_style, set-show
4857: @subsection dgrid3d
4858:
4859: @c ?commands set dgrid3d
4860: @c ?commands set nodgrid3d
4861: @c ?commands show dgrid3d
4862: @c ?set dgrid3d
4863: @c ?set nodgrid3d
4864: @c ?show dgrid3d
4865: @cindex dgrid3d
4866: @opindex dgrid3d
4867:
4868:
4869: @cindex nodgrid3d
4870:
4871: The @ref{dgrid3d} command enables, and can set parameters for, non-grid
4872: to grid data mapping.
4873:
4874: Syntax:
4875: @example
4876: set dgrid3d @{<row_size>@} @{,@{<col_size>@} @{,<norm>@}@}
4877: set nodgrid3d
4878: show dgrid3d
4879:
4880: @end example
4881:
4882: By default @ref{dgrid3d} is disabled. When enabled, 3-d data read from a file
4883: are always treated as a scattered data set. A grid with dimensions derived
4884: from a bounding box of the scattered data and size as specified by the
4885: row/col_size parameters is created for plotting and contouring. The grid
4886: is equally spaced in x (rows) and in y (columns); the z values are computed
4887: as weighted averages of the scattered points' z values.
4888:
4889: The third parameter, norm, controls the weighting: Each data point is
4890: weighted inversely by its distance from the grid point raised to the norm
4891: power. (Actually, the weights are given by the inverse of dx^norm + dy^norm,
4892: where dx and dy are the components of the separation of the grid point from
4893: each data point. For some norms that are powers of two, specifically 4, 8,
4894: and 16, the computation is optimized by using the Euclidean distance in the
4895: weight calculation, (dx^2+dx^2)^norm/2. However, any non-negative integer
4896: can be used.)
4897:
4898: The closer the data point is to a grid point, the more effect it has on
4899: that grid point and the larger the value of norm the less effect more
4900: distant data points have on that grid point.
4901:
4902: The @ref{dgrid3d} option is a simple low pass filter that converts scattered
4903: data to a grid data set. More sophisticated approaches to this problem
4904: exist and should be used to preprocess the data outside `gnuplot` if this
4905: simple solution is found inadequate.
4906:
4907: (The z values are found by weighting all data points, not by interpolating
4908: between nearby data points; also edge effects may produce unexpected and/or
4909: undesired results. In some cases, small norm values produce a grid point
4910: reflecting the average of distant data points rather than a local average,
4911: while large values of norm may produce "steps" with several grid points
4912: having the same value as the closest data point, rather than making a smooth
4913: transition between adjacent data points. Some areas of a grid may be filled
4914: by extrapolation, to an arbitrary boundary condition. The variables are
4915: not normalized; consequently the units used for x and y will affect the
4916: relative weights of points in the x and y directions.)
4917:
4918: Examples:
4919: @example
4920: set dgrid3d 10,10,1 # defaults
4921: set dgrid3d ,,4
4922:
4923: @end example
4924:
4925: The first specifies that a grid of size 10 by 10 is to be constructed using
4926: a norm value of 1 in the weight computation. The second only modifies the
4927: norm, changing it to 4.
4928: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/scatter.html,Dgrid3d Demo.}
4929:
4930:
4931: @node dummy, encoding, dgrid3d, set-show
4932: @subsection dummy
4933:
4934: @c ?commands set dummy
4935: @c ?commands show dummy
4936: @c ?set dummy
4937: @c ?show dummy
4938: @cindex dummy
4939: @opindex dummy
4940:
4941:
4942: The @ref{dummy} command changes the default dummy variable names.
4943:
4944: Syntax:
4945: @example
4946: set dummy @{<dummy-var>@} @{,<dummy-var>@}
4947: show dummy
4948:
4949: @end example
4950:
4951: By default, `gnuplot` assumes that the independent, or "dummy", variable for
4952: the @ref{plot} command is "t" if in parametric or polar mode, or "x" otherwise.
4953: Similarly the independent variables for the `splot` command are "u" and "v"
4954: in parametric mode (`splot` cannot be used in polar mode), or "x" and "y"
4955: otherwise.
4956:
4957: It may be more convenient to call a dummy variable by a more physically
4958: meaningful or conventional name. For example, when plotting time functions:
4959:
4960: @example
4961: set dummy t
4962: plot sin(t), cos(t)
4963:
4964: @end example
4965:
4966: At least one dummy variable must be set on the command; @ref{dummy} by itself
4967: will generate an error message.
4968:
4969: Examples:
4970: @example
4971: set dummy u,v
4972: set dummy ,s
4973:
4974: @end example
4975:
4976: The second example sets the second variable to s.
4977:
4978: @node encoding, format, dummy, set-show
4979: @subsection encoding
4980:
4981: @c ?commands set encoding
4982: @c ?commands show encoding
4983: @c ?set encoding
4984: @c ?show encoding
4985: @cindex encoding
4986: @opindex encoding
4987:
4988:
4989: The @ref{encoding} command selects a character encoding. Valid values are
4990: `default`, which tells a terminal to use its default; `iso_8859_1` (known in
4991: the PostScript world as `ISO-Latin1`), which is used on many Unix workstations
4992: and with MS-Windows; `cp850`, for OS/2; and `cp437`, for MS-DOS.
4993:
4994: Syntax:
4995: @example
4996: set encoding @{<value>@}
4997: show encoding
4998:
4999: @end example
5000:
5001: Note that encoding is not supported by all terminal drivers and that
5002: the device must be able to produce the desired non-standard characters.
5003:
5004: @node format, function_style, encoding, set-show
5005: @subsection format
5006:
5007: @c ?commands set format
5008: @c ?commands show format
5009: @c ?set format
5010: @c ?show format
5011: @cindex format
5012: @opindex format
5013:
5014:
5015: The format of the tic-mark labels can be set with the `set format` command.
5016:
5017: Syntax:
5018: @example
5019: set format @{<axes>@} @{"<format-string>"@}
5020: set format @{<axes>@} @{'<format-string>'@}
5021: show format
5022:
5023: @end example
5024:
5025: where <axes> is either `x`, `y`, `z`, `xy`, `x2`, `y2` or nothing (which is
5026: the same as `xy`). The length of the string representing a tic mark (after
5027: formatting with 'printf') is restricted to 100 characters. If the format
5028: string is omitted, the format will be returned to the default "%g". For
5029: LaTeX users, the format "$%g$" is often desirable. If the empty string "" is
5030: used, no label will be plotted with each tic, though the tic mark will still
5031: be plotted. To eliminate all tic marks, use `set noxtics` or `set noytics`.
5032:
5033: Newline (\n) is accepted in the format string. Use double-quotes rather than
5034: single-quotes to enable such interpretation. See also `syntax`.
5035:
5036: The default format for both axes is "%g", but other formats such as "%.2f" or
5037: "%3.0em" are often desirable. Anything accepted by 'printf' when given a
5038: double precision number, and accepted by the terminal, will work. Some other
5039: options have been added. If the format string looks like a floating point
5040: format, then `gnuplot` tries to construct a reasonable format.
5041:
5042: Characters not preceded by "%" are printed verbatim. Thus you can include
5043: spaces and labels in your format string, such as "%g m", which will put " m"
5044: after each number. If you want "%" itself, double it: "%g %%".
5045:
5046: See also @ref{xtics} for more information about tic labels.
5047: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/electron.html,See demo. }
5048:
5049: @menu
5050: * format_specifiers::
5051: * time/date_specifiers::
5052: @end menu
5053:
5054: @node format_specifiers, time/date_specifiers, format, format
5055: @subsubsection format specifiers
5056:
5057: @c ?commands set format specifiers
5058: @c ?set format specifiers
5059: @c ?format specifiers
5060: @cindex format_specifiers
5061:
5062: The acceptable formats (if not in time/date mode) are:
5063:
5064:
5065: @example
5066: Format Explanation
5067: %f floating point notation
5068: %e or %E exponential notation; an "e" or "E" before the power
5069: %g or %G the shorter of %e (or %E) and %f
5070: %x or %X hex
5071: %o or %O octal
5072: %t mantissa to base 10
5073: %l mantissa to base of current logscale
5074: %s mantissa to base of current logscale; scientific power
5075: %T power to base 10
5076: %L power to base of current logscale
5077: %S scientific power
5078: %c character replacement for scientific power
5079: %P multiple of pi
5080:
5081: @end example
5082:
5083:
5084: A 'scientific' power is one such that the exponent is a multiple of three.
5085: Character replacement of scientific powers (`"%c"`) has been implemented
5086: for powers in the range -18 to +18. For numbers outside of this range the
5087: format reverts to exponential.
5088:
5089: Other acceptable modifiers (which come after the "%" but before the format
5090: specifier) are "-", which left-justifies the number; "+", which forces all
5091: numbers to be explicitly signed; "#", which places a decimal point after
5092: floats that have only zeroes following the decimal point; a positive integer,
5093: which defines the field width; "0" (the digit, not the letter) immediately
5094: preceding the field width, which indicates that leading zeroes are to be used
5095: instead of leading blanks; and a decimal point followed by a non-negative
5096: integer, which defines the precision (the minimum number of digits of an
5097: integer, or the number of digits following the decimal point of a float).
5098:
5099: Some releases of 'printf' may not support all of these modifiers but may also
5100: support others; in case of doubt, check the appropriate documentation and
5101: then experiment.
5102:
5103: Examples:
5104: @example
5105: set format y "%t"; set ytics (5,10) # "5.0" and "1.0"
5106: set format y "%s"; set ytics (500,1000) # "500" and "1.0"
5107: set format y "+-12.3f"; set ytics(12345) # "+12345.000 "
5108: set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
5109: set format y "%s*10^@{%S@}"; set ytic(12345) # "12.345*10^@{3@}"
5110: set format y "%s %cg"; set ytic(12345) # "12.345 kg"
5111: set format y "%.0P pi"; set ytic(6.283185) # "2 pi"
5112: set format y "%.0P%%"; set ytic(50) # "50%"
5113:
5114: @end example
5115:
5116: @example
5117: set log y 2; set format y '%l'; set ytics (1,2,3)
5118: #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)
5119:
5120: @end example
5121:
5122: There are some problem cases that arise when numbers like 9.999 are printed
5123: with a format that requires both rounding and a power.
5124:
5125: If the data type for the axis is time/date, the format string must contain
5126: valid codes for the 'strftime' function (outside of `gnuplot`, type "man
5127: strftime"). See @ref{timefmt} for a list of the allowed input format codes.
5128:
5129: @node time/date_specifiers, , format_specifiers, format
5130: @subsubsection time/date specifiers
5131:
5132: @c ?commands set format time/date_specifiers
5133: @c ?set format time/date_specifiers
5134: @c ?set time/date_specifiers
5135: @cindex time/date_specifiers
5136:
5137: In time/date mode, the acceptable formats are:
5138:
5139:
5140: @example
5141: Format Explanation
5142: %a abbreviated name of day of the week
5143: %A full name of day of the week
5144: %b or %h abbreviated name of the month
5145: %B full name of the month
5146: %d day of the month, 1--31
5147: %D shorthand for "%m/%d/%y"
5148: %H or %k hour, 0--24
5149: %I or %l hour, 0--12
5150: %j day of the year, 1--366
5151: %m month, 1--12
5152: %M minute, 0--60
5153: %p "am" or "pm"
5154: %r shorthand for "%I:%M:%S %p"
1.1.1.2 ! ohara 5155: %R shorthand for "%H:%M"
1.1 maekawa 5156: %S second, 0--60
5157: %T shorthand for "%H:%M:%S"
5158: %U week of the year (week starts on Sunday)
5159: %w day of the week, 0--6 (Sunday = 0)
5160: %W week of the year (week starts on Monday)
5161: %y year, 0-99
5162: %Y year, 4-digit
5163:
5164: @end example
5165:
5166:
5167: Except for the non-numerical formats, these may be preceded by a "0" ("zero",
5168: not "oh") to pad the field length with leading zeroes, and a positive digit,
5169: to define the minimum field width (which will be overridden if the specified
5170: width is not large enough to contain the number). There is a 24-character
5171: limit to the length of the printed text; longer strings will be truncated.
5172:
5173: Examples:
5174:
5175: Suppose the text is "76/12/25 23:11:11". Then
5176: @example
5177: set format x # defaults to "12/25/76" \n "23:11"
5178: set format x "%A, %d %b %Y" # "Saturday, 25 Dec 1976"
5179: set format x "%r %d" # "11:11:11 pm 12/25/76"
5180:
5181: @end example
5182:
5183: Suppose the text is "98/07/06 05:04:03". Then
5184: @example
5185: set format x "%1y/%2m/%3d %01H:%02M:%03S" # "98/ 7/ 6 5:04:003"
5186:
5187: @end example
5188:
5189: @node function_style, functions, format, set-show
5190: @subsection function style
5191:
5192: @c ?commands set function style
5193: @c ?commands show function style
5194: @c ?set function style
5195: @c ?show function style
5196: @c ?function style
5197: The @ref{style} command changes the default plotting style for
5198: function plots.
5199:
5200: Syntax:
5201: @example
5202: set function style <style-choice>
5203: show function style
5204:
5205: @end example
5206:
5207: See @ref{style} for the choices. If no choice is given, the choices are
5208: listed. @ref{style} shows the current default function plotting
5209: style.
5210:
5211: @node functions, grid, function_style, set-show
5212: @subsection functions
5213:
5214: @c ?commands show functions
5215: @c ?show functions
5216: The @ref{functions} command lists all user-defined functions and their
5217: definitions.
5218:
5219: Syntax:
5220: @example
5221: show functions
5222:
5223: @end example
5224:
5225: For information about the definition and usage of functions in `gnuplot`,
5226: please see `expressions`.
5227: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/spline.html,Splines as User Defined Functions.}
5228: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/airfoil.html,Use of functions and complex variables for airfoils }
5229:
5230: @node grid, hidden3d, functions, set-show
5231: @subsection grid
5232:
5233: @c ?commands set grid
5234: @c ?commands set nogrid
5235: @c ?commands show grid
5236: @c ?set grid
5237: @c ?set nogrid
5238: @c ?show grid
5239: @cindex grid
5240: @opindex grid
5241:
5242:
5243: @cindex nogrid
5244:
5245: The `set grid` command allows grid lines to be drawn on the plot.
5246:
5247: Syntax:
5248: @example
5249: set grid @{@{no@}@{m@}xtics@} @{@{no@}@{m@}ytics@} @{@{no@}@{m@}ztics@}
5250: @{@{no@}@{m@}x2tics@} @{@{no@}@{m@}y2tics@}
5251: @{polar @{<angle>@}@}
5252: @{ @{linestyle <major_linestyle>@}
5253: | @{linetype | lt <major_linetype>@}
5254: @{linewidth | lw <major_linewidth>@}
5255: @{ , @{linestyle | ls <minor_linestyle>@}
5256: | @{linetype | lt <minor_linetype>@}
5257: @{linewidth | lw <minor_linewidth>@} @} @}
5258: set nogrid
5259: show grid
5260:
5261: @end example
5262:
5263: The grid can be enabled and disabled for the major and/or minor tic
5264: marks on any axis, and the linetype and linewidth can be specified
5265: for major and minor grid lines, also via a predefined linestyle, as
5266: far as the active terminal driver supports this.
5267:
5268: Additionally, a polar grid can be selected for 2-d plots---circles are drawn
5269: to intersect the selected tics, and radial lines are drawn at definable
5270: intervals. (The interval is given in degrees or radians ,depending on the
5271: @ref{angles} setting.) Note that a polar grid is no longer automatically
5272: generated in polar mode.
5273:
5274: The pertinent tics must be enabled before `set grid` can draw them; `gnuplot`
5275: will quietly ignore instructions to draw grid lines at non-existent tics, but
5276: they will appear if the tics are subsequently enabled.
5277:
5278: If no linetype is specified for the minor gridlines, the same linetype as the
5279: major gridlines is used. The default polar angle is 30 degrees.
5280:
5281: By default, grid lines are drawn with half the usual linewidth. The major and
5282: minor linewidth specifiers scale this default value; for example, `set grid
5283: lw .5` will draw grid lines with one quarter the usual linewidth.
5284:
5285: Z grid lines are drawn on the back of the plot. This looks better if a
5286: partial box is drawn around the plot---see @ref{border}.
5287:
5288: @node hidden3d, isosamples, grid, set-show
5289: @subsection hidden3d
5290:
5291: @c ?commands set hidden3d
5292: @c ?commands set nohidden3d
5293: @c ?commands show hidden3d
5294: @c ?set hidden3d
5295: @c ?set nohidden3d
5296: @c ?show hidden3d
5297: @cindex hidden3d
5298: @opindex hidden3d
5299:
5300:
5301: @cindex nohidden3d
5302:
5303: The @ref{hidden3d} command enables hidden line removal for surface plotting
5304: (see `splot`). Some optional features of the underlying algorithm can also
5305: be controlled using this command.
5306:
5307: Syntax:
5308: @example
5309: set hidden3d @{defaults@} |
5310: @{ @{@{offset <offset>@} | @{nooffset@}@}
5311: @{trianglepattern <bitpattern>@}
5312: @{@{undefined <level>@} | @{noundefined@}@}
5313: @{@{no@}altdiagonal@}
5314: @{@{no@}bentover@} @}
5315: set nohidden3d
5316: show hidden3d
5317:
5318: @end example
5319:
5320: In contrast to the usual display in gnuplot, hidden line removal actually
5321: treats the given function or data grids as real surfaces that can't be seen
5322: through, so parts behind the surface will be hidden by it. For this to be
5323: possible, the surface needs to have 'grid structure' (see `splot datafile`
5324: about this), and it has to be drawn `with lines` or @ref{linespoints}.
5325:
5326: When @ref{hidden3d} is set, both the hidden portion of the surface and possibly
5327: its contours drawn on the base (see @ref{contour}) as well as the grid will
5328: be hidden. Each surface has its hidden parts removed with respect to itself
5329: and to other surfaces, if more than one surface is plotted. Contours drawn
5330: on the surface (@ref{surface}) don't work. Labels and arrows are
5331: always visible and are unaffected. The key is also never hidden by the
5332: surface.
5333:
5334: Functions are evaluated at isoline intersections. The algorithm interpolates
5335: linearly between function points or data points when determining the visible
5336: line segments. This means that the appearance of a function may be different
5337: when plotted with @ref{hidden3d} than when plotted with `nohidden3d` because in
5338: the latter case functions are evaluated at each sample. Please see @ref{samples} and @ref{isosamples} for discussion of the difference.
5339:
5340: The algorithm used to remove the hidden parts of the surfaces has some
5341: additional features controllable by this command. Specifying `defaults` will
5342: set them all to their default settings, as detailed below. If `defaults` is
5343: not given, only explicitly specified options will be influenced: all others
5344: will keep their previous values, so you can turn on/off hidden line removal
5345: via `set @{no@}hidden3d`, without modifying the set of options you chose.
5346:
5347: The first option, `offset`, influences the linestyle used for lines on the
5348: 'back' side. Normally, they are drawn in a linestyle one index number higher
5349: than the one used for the front, to make the two sides of the surface
5350: distinguishable. You can specify a different line style offset to add
5351: instead of the default 1, by `offset <offset>`. Option `nooffset` stands for
5352: `offset 0`, making the two sides of the surface use the same linestyle.
5353:
5354: Next comes the option `trianglepattern <bitpattern>`. <bitpattern> must be
5355: a number between 0 and 7, interpreted as a bit pattern. Each bit determines
5356: the visibility of one edge of the triangles each surface is split up into.
5357: Bit 0 is for the 'horizontal' edges of the grid, Bit 1 for the 'vertical'
5358: ones, and Bit 2 for the diagonals that split each cell of the original grid
5359: into two triangles. The default pattern is 3, making all horizontal and
5360: vertical lines visible, but not the diagonals. You may want to choose 7 to
5361: see those diagonals as well.
5362:
5363: The `undefined <level>` option lets you decide what the algorithm is to do
5364: with data points that are undefined (missing data, or undefined function
5365: values), or exceed the given x-, y- or z-ranges. Such points can either be
5366: plotted nevertheless, or taken out of the input data set. All surface
5367: elements touching a point that is taken out will be taken out as well, thus
5368: creating a hole in the surface. If <level> = 3, equivalent to option
5369: `noundefined`, no points will be thrown away at all. This may produce all
5370: kinds of problems elsewhere, so you should avoid this. <level> = 2 will
5371: throw away undefined points, but keep the out-of-range ones. <level> = 1,
5372: the default, will get rid of out-of-range points as well.
5373:
5374: By specifying `noaltdiagonal`, you can override the default handling of a
5375: special case can occur if `undefined` is active (i.e. <level> is not 3).
5376: Each cell of the grid-structured input surface will be divided in two
5377: triangles along one of its diagonals. Normally, all these diagonals have
5378: the same orientation relative to the grid. If exactly one of the four cell
5379: corners is excluded by the `undefined` handler, and this is on the usual
5380: diagonal, both triangles will be excluded. However if the default setting
5381: of `altdiagonal` is active, the other diagonal will be chosen for this cell
5382: instead, minimizing the size of the hole in the surface.
5383:
5384: The `bentover` option controls what happens to another special case, this
5385: time in conjunction with the `trianglepattern`. For rather crumply surfaces,
5386: it can happen that the two triangles a surface cell is divided into are seen
5387: from opposite sides (i.e. the original quadrangle is 'bent over'), as
5388: illustrated in the following ASCII art:
5389:
5390: @example
5391: C----B
5392: original quadrangle: A--B displayed quadrangle: |\ |
5393: ("set view 0,0") | /| ("set view 75,75" perhaps) | \ |
5394: |/ | | \ |
5395: C--D | \|
5396: A D
5397:
5398: @end example
5399:
5400: If the diagonal edges of the surface cells aren't generally made visible by
5401: bit 2 of the <bitpattern> there, the edge CB above wouldn't be drawn at all,
5402: normally, making the resulting display hard to understand. Therefore, the
5403: default option of `bentover` will turn it visible in this case. If you don't
5404: want that, you may choose `nobentover` instead.
5405: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/hidden.html,Hidden Line Removal Demo} and
5406: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/singulr.html,Complex Hidden Line Demo. }
5407:
5408: @node isosamples, key, hidden3d, set-show
5409: @subsection isosamples
5410:
5411: @c ?commands set isosamples
5412: @c ?commands show isosamples
5413: @c ?set isosamples
5414: @c ?show isosamples
5415: @cindex isosamples
5416: @opindex isosamples
5417:
5418:
5419: The isoline density (grid) for plotting functions as surfaces may be changed
5420: by the @ref{isosamples} command.
5421:
5422: Syntax:
5423: @example
5424: set isosamples <iso_1> @{,<iso_2>@}
5425: show isosamples
5426:
5427: @end example
5428:
5429: Each function surface plot will have <iso_1> iso-u lines and <iso_2> iso-v
5430: lines. If you only specify <iso_1>, <iso_2> will be set to the same value
5431: as <iso_1>. By default, sampling is set to 10 isolines per u or v axis.
5432: A higher sampling rate will produce more accurate plots, but will take longer.
5433: These parameters have no effect on data file plotting.
5434:
5435: An isoline is a curve parameterized by one of the surface parameters while
5436: the other surface parameter is fixed. Isolines provide a simple means to
5437: display a surface. By fixing the u parameter of surface s(u,v), the iso-u
5438: lines of the form c(v) = s(u0,v) are produced, and by fixing the v parameter,
5439: the iso-v lines of the form c(u) = s(u,v0) are produced.
5440:
5441: When a function surface plot is being done without the removal of hidden
5442: lines, @ref{samples} controls the number of points sampled along each
5443: isoline; see @ref{samples} and @ref{hidden3d}. The contour algorithm
5444: assumes that a function sample occurs at each isoline intersection, so
5445: change in @ref{samples} as well as @ref{isosamples} may be desired when changing
5446: the resolution of a function surface/contour.
5447:
5448: @node key, label, isosamples, set-show
5449: @subsection key
5450:
5451: @c ?commands set key
5452: @c ?commands set nokey
5453: @c ?commands show key
5454: @c ?set key
5455: @c ?set nokey
5456: @c ?show key
5457: @cindex key
5458: @opindex key
5459:
5460:
5461: @cindex nokey
5462:
5463: @cindex legend
5464:
5465: The @ref{key} enables a key (or legend) describing plots on a plot.
5466:
5467: The contents of the key, i.e., the names given to each plotted data set and
5468: function and samples of the lines and/or symbols used to represent them, are
5469: determined by the `title` and @ref{with} options of the @{`s`@}@ref{plot} command.
5470: Please see `plot title` and @ref{with} for more information.
5471:
5472: Syntax:
5473: @example
5474: set key @{ left | right | top | bottom | outside | below
5475: | <position>@}
5476: @{Left | Right@} @{@{no@}reverse@}
5477: @{samplen <sample_length>@} @{spacing <vertical_spacing>@}
5478: @{width <width_increment>@}
5479: @{title "<text>"@}
5480: @{@{no@}box @{ @{linestyle | ls <line_style>@}
5481: | @{linetype | lt <line_type>@}
5482: @{linewidth | lw <line_width>@}@}@}
5483: set nokey
5484: show key
5485:
5486: @end example
5487:
5488: By default the key is placed in the upper right corner of the graph. The
5489: keywords `left`, `right`, `top`, `bottom`, `outside` and `below` may be used
5490: to place the key in the other corners inside the graph or to the right
5491: (outside) or below the graph. They may be given alone or combined.
5492:
5493: Justification of the labels within the key is controlled by `Left` or `Right`
5494: (default is `Right`). The text and sample can be reversed (`reverse`) and a
5495: box can be drawn around the key (`box @{...@}`) in a specified `linetype`
5496: and `linewidth`, or a user-defined @ref{linestyle}. Note that not all
5497: terminal drivers support linewidth selection, though.
5498:
5499: The length of the sample line can be controlled by `samplen`. The sample
5500: length is computed as the sum of the tic length and <sample_length> times the
5501: character width. `samplen` also affects the positions of point samples in
5502: the key since these are drawn at the midpoint of the sample line, even if it
5503: is not drawn. <sample_length> must be an integer.
5504:
5505: The vertical spacing between lines is controlled by `spacing`. The spacing
5506: is set equal to the product of the pointsize, the vertical tic size, and
5507: <vertical_spacing>. The program will guarantee that the vertical spacing is
5508: no smaller than the character height.
5509:
5510: The <width_increment> is a number of character widths to be added to or
5511: subtracted from the length of the string. This is useful only when you are
5512: putting a box around the key and you are using control characters in the text.
5513: `gnuplot` simply counts the number of characters in the string when computing
5514: the box width; this allows you to correct it.
5515:
5516: A title can be put on the key (`title "<text>"`)---see also `syntax` for the
5517: distinction between text in single- or double-quotes. The key title uses the
5518: same justification as do the plot titles.
5519:
5520: The defaults for @ref{key} are `right`, `top`, `Right`, `noreverse`, `samplen
5521: 4`, `spacing 1.25`, `title ""`, and `nobox`. The default <linetype> is the
5522: same as that used for the plot borders. Entering @ref{key} with no options
5523: returns the key to its default configuration.
5524:
5525: The <position> can be a simple x,y,z as in previous versions, but these can
5526: be preceded by one of four keywords (`first`, `second`, `graph`, `screen`)
5527: which selects the coordinate system in which the position is specified. See
5528: `coordinates` for more details.
5529:
5530: The key is drawn as a sequence of lines, with one plot described on each
5531: line. On the right-hand side (or the left-hand side, if `reverse` is
5532: selected) of each line is a representation that attempts to mimic the way the
5533: curve is plotted. On the other side of each line is the text description
5534: (the line title), obtained from the @ref{plot} command. The lines are vertically
5535: arranged so that an imaginary straight line divides the left- and right-hand
5536: sides of the key. It is the coordinates of the top of this line that are
5537: specified with the @ref{key} command. In a @ref{plot}, only the x and y
5538: coordinates are used to specify the line position. For a `splot`, x, y and
5539: z are all used as a 3-d location mapped using the same mapping as the graph
5540: itself to form the required 2-d screen position of the imaginary line.
5541:
5542: Some or all of the key may be outside of the graph boundary, although this
5543: may interfere with other labels and may cause an error on some devices. If
5544: you use the keywords `outside` or `below`, `gnuplot` makes space for the keys
5545: and the graph becomes smaller. Putting keys outside to the right, they
5546: occupy as few columns as possible, and putting them below, as many columns as
5547: possible (depending of the length of the labels), thus stealing as little
5548: space from the graph as possible.
5549:
5550: When using the TeX or PostScript drivers, or similar drivers where formatting
5551: information is embedded in the string, `gnuplot` is unable to calculate
5552: correctly the width of the string for key positioning. If the key is to be
5553: positioned at the left, it may be convenient to use the combination `set key
5554: left Left reverse`. The box and gap in the grid will be the width of the
5555: literal string.
5556:
5557: If `splot` is being used to draw contours, the contour labels will be listed
5558: in the key. If the alignment of these labels is poor or a different number
5559: of decimal places is desired, the label format can be specified. See @ref{clabel} for details.
5560:
5561: Examples:
5562:
5563: This places the key at the default location:
5564: @example
5565: set key
5566:
5567: @end example
5568:
5569: This disables the key:
5570: @example
5571: set nokey
5572:
5573: @end example
5574:
5575: This places a key at coordinates 2,3.5,2 in the default (first) coordinate
5576: system:
5577: @example
5578: set key 2,3.5,2
5579:
5580: @end example
5581:
5582: This places the key below the graph:
5583: @example
5584: set key below
5585:
5586: @end example
5587:
5588: This places the key in the bottom left corner, left-justifies the text,
5589: gives it a title, and draws a box around it in linetype 3:
5590: @example
5591: set key left bottom Left title 'Legend' box 3
5592:
5593: @end example
5594:
5595: @node label, linestyle, key, set-show
5596: @subsection label
5597:
5598: @c ?commands set label
5599: @c ?commands set nolabel
5600: @c ?commands show label
5601: @c ?set label
5602: @c ?set nolabel
5603: @c ?show label
5604: @cindex label
5605: @opindex label
5606:
5607:
5608: @cindex nolabel
5609:
5610: Arbitrary labels can be placed on the plot using the @ref{label} command.
5611:
5612: Syntax:
5613: @example
5614: set label @{<tag>@} @{"<label_text>"@} @{at <position>@}
5615: @{<justification>@} @{@{no@}rotate@} @{font "<name><,size>"@}
5616: set nolabel @{<tag>@}
5617: show label
5618:
5619: @end example
5620:
5621: The <position> is specified by either x,y or x,y,z, and may be preceded by
5622: `first`, `second`, `graph`, or `screen` to select the coordinate system.
5623: See `coordinates` for details.
5624:
5625: The tag is an integer that is used to identify the label. If no <tag> is
5626: given, the lowest unused tag value is assigned automatically. The tag can be
5627: used to delete or modify a specific label. To change any attribute of an
5628: existing label, use the @ref{label} command with the appropriate tag, and
5629: specify the parts of the label to be changed.
5630:
5631: By default, the text is placed flush left against the point x,y,z. To adjust
5632: the way the label is positioned with respect to the point x,y,z, add the
5633: parameter <justification>, which may be `left`, `right` or `center`,
5634: indicating that the point is to be at the left, right or center of the text.
5635: Labels outside the plotted boundaries are permitted but may interfere with
5636: axis labels or other text.
5637:
5638: If `rotate` is given, the label is written vertically (if the terminal can do
5639: so, of course).
5640:
5641: If one (or more) axis is timeseries, the appropriate coordinate should be
5642: given as a quoted time string according to the @ref{timefmt} format string. See
5643: @ref{xdata} and @ref{timefmt}.
5644:
5645: The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
5646: a newline.
5647:
5648: Examples:
5649:
5650: To set a label at (1,2) to "y=x", use:
5651: @example
5652: set label "y=x" at 1,2
5653:
5654: @end example
5655:
5656: To set a Sigma of size 24, from the Symbol font set, at the center of
5657: the graph, use:
5658: @example
5659: set label "S" at graph 0.5,0.5 center font "Symbol,24"
5660:
5661: @end example
5662:
5663: To set a label "y=x^2" with the right of the text at (2,3,4), and tag the
5664: label as number 3, use:
5665: @example
5666: set label 3 "y=x^2" at 2,3,4 right
5667:
5668: @end example
5669:
5670: To change the preceding label to center justification, use:
5671: @example
5672: set label 3 center
5673:
5674: @end example
5675:
5676: To delete label number 2, use:
5677: @example
5678: set nolabel 2
5679:
5680: @end example
5681:
5682: To delete all labels, use:
5683: @example
5684: set nolabel
5685:
5686: @end example
5687:
5688: To show all labels (in tag order), use:
5689: @example
5690: show label
5691:
5692: @end example
5693:
5694: To set a label on a graph with a timeseries on the x axis, use, for example:
5695: @example
5696: set timefmt "%d/%m/%y,%H:%M"
5697: set label "Harvest" at "25/8/93",1
5698:
5699: @end example
5700:
5701: @node linestyle, lmargin, label, set-show
5702: @subsection linestyle
5703:
5704: @c ?commands set linestyle
5705: @c ?commands set nolinestyle
5706: @c ?commands show linestyle
5707: @c ?set linestyle
5708: @c ?set nolinestyle
5709: @c ?show linestyle
5710: @cindex linestyle
5711: @opindex linestyle
5712:
5713:
5714: Each terminal has a default set of line and point types, which can be seen
5715: by using the command @ref{test}. @ref{linestyle} defines a set of line types
5716: and widths and point types and sizes so that you can refer to them later by
5717: an index instead of repeating all the information at each invocation.
5718:
5719: Syntax:
5720: @example
5721: set linestyle <index> @{linetype | lt <line_type>@}
5722: @{linewidth | lw <line_width>@}
5723: @{pointtype | pt <point_type>@}
5724: @{pointsize | ps <point_size>@}
5725: set nolinestyle
5726: show linestyle
5727:
5728: @end example
5729:
5730: The line and point types are taken from the default types for the terminal
5731: currently in use. The line width and point size are multipliers for the
5732: default width and size (but note that <point_size> here is unaffected by
5733: the multiplier given on 'set pointsize').
5734:
5735: The defaults for the line and point types is the index. The defaults for
5736: the width and size are both unity.
5737:
5738: Linestyles created by this mechanism do not replace the default styles;
5739: both may be used.
5740:
5741: Not all terminals support the `linewidth` and @ref{pointsize} features; if
5742: not supported, the option will be ignored.
5743:
5744: Note that this feature is not completely implemented; linestyles defined by
5745: this mechanism may be used with 'plot', 'splot', 'replot', and 'set arrow',
5746: but not by other commands that allow the default index to be used, such as
5747: 'set grid'.
5748:
5749: Example:
5750: Suppose that the default lines for indices 1, 2, and 3 are red, green, and
5751: blue, respectively, and the default point shapes for the same indices are a
5752: square, a cross, and a triangle, respectively. Then
5753:
5754: @example
5755: set linestyle 1 lt 2 lw 2 pt 3 ps 0.5
5756:
5757: @end example
5758:
5759: defines a new linestyle that is green and twice the default width and a new
5760: pointstyle that is a half-sized triangle. The commands
5761:
5762: @example
5763: set function style lines
5764: plot f(x) lt 3, g(x) ls 1
5765:
5766: @end example
5767:
5768: will create a plot of f(x) using the default blue line and a plot of g(x)
5769: using the user-defined wide green line. Similarly the commands
5770:
5771: @example
5772: set function style linespoints
5773: plot p(x) lt 1 pt 3, q(x) ls 1
5774:
5775: @end example
5776:
5777: will create a plot of f(x) using the default triangles connected by a red
5778: line and q(x) using small triangles connected by a green line.
5779:
5780: @node lmargin, locale, linestyle, set-show
5781: @subsection lmargin
5782:
5783: @c ?commands set lmargin
5784: @c ?set lmargin
5785: @cindex lmargin
5786: @opindex lmargin
5787:
5788:
5789: The command @ref{lmargin} sets the size of the left margin. Please see
5790: @ref{margin} for details.
5791:
5792: @node locale, logscale, lmargin, set-show
5793: @subsection locale
5794:
5795: @c ?commands set locale
5796: @c ?commands show logscale
5797: @c ?set locale
5798: @c ?show logscale
5799: @cindex locale
5800: @opindex locale
5801:
5802:
5803: The @ref{locale} setting determines the language with which `@{x,y,z@}@{d,m@}tics`
5804: will write the days and months.
5805:
5806: Syntax:
5807: @example
5808: set locale @{"<locale>"@}
5809:
5810: @end example
5811:
5812: <locale> may be any language designation acceptable to your installation.
5813: See your system documentation for the available options. The default value
5814: is determined from the LANG environment variable.
5815:
5816: @node logscale, mapping, locale, set-show
5817: @subsection logscale
5818:
5819: @c ?commands set logscale
5820: @c ?commands set nologscale
5821: @c ?commands show logscale
5822: @c ?set logscale
5823: @c ?set nologscale
5824: @c ?show logscale
5825: @cindex logscale
5826: @opindex logscale
5827:
5828:
5829: @cindex nologscale
5830:
5831: Log scaling may be set on the x, y, z, x2 and/or y2 axes.
5832:
5833: Syntax:
5834: @example
5835: set logscale <axes> <base>
5836: set nologscale <axes>
5837: show logscale
5838:
5839: @end example
5840:
5841: where <axes> may be any combinations of `x`, `y`, and `z`, in any order, or
5842: `x2` or `y2` and where <base> is the base of the log scaling. If <base> is
5843: not given, then 10 is assumed. If <axes> is not given, then all axes are
5844: assumed. `set nologscale` turns off log scaling for the specified axes.
5845:
5846: Examples:
5847:
5848: To enable log scaling in both x and z axes:
5849: @example
5850: set logscale xz
5851:
5852: @end example
5853:
5854: To enable scaling log base 2 of the y axis:
5855: @example
5856: set logscale y 2
5857:
5858: @end example
5859:
5860: To disable z axis log scaling:
5861: @example
5862: set nologscale z
5863:
5864: @end example
5865:
5866: @node mapping, margin, logscale, set-show
5867: @subsection mapping
5868:
5869: @c ?commands set mapping
5870: @c ?commands show mapping
5871: @c ?set mapping
5872: @c ?show mapping
5873: @cindex mapping
5874: @opindex mapping
5875:
5876:
5877: If data are provided to `splot` in spherical or cylindrical coordinates,
5878: the @ref{mapping} command should be used to instruct `gnuplot` how to
5879: interpret them.
5880:
5881: Syntax:
5882: @example
5883: set mapping @{cartesian | spherical | cylindrical@}
5884:
5885: @end example
5886:
5887: A cartesian coordinate system is used by default.
5888:
5889: For a spherical coordinate system, the data occupy two or three columns (or
5890: @ref{using} entries). The first two are interpreted as the polar and azimuthal
5891: angles theta and phi (in the units specified by @ref{angles}). The radius r
5892: is taken from the third column if there is one, or is set to unity if there
5893: is no third column. The mapping is:
5894:
5895: @example
5896: x = r * cos(theta) * cos(phi)
5897: y = r * sin(theta) * cos(phi)
5898: z = r * sin(phi)
5899:
5900: @end example
5901:
5902: Note that this is a "geographic" spherical system, rather than a "polar" one.
5903:
5904: For a cylindrical coordinate system, the data again occupy two or three
5905: columns. The first two are interpreted as theta (in the units specified by
5906: @ref{angles}) and z. The radius is either taken from the third column or set
5907: to unity, as in the spherical case. The mapping is:
5908:
5909: @example
5910: x = r * cos(theta)
5911: y = r * sin(theta)
5912: z = z
5913:
5914: @end example
5915:
5916: The effects of @ref{mapping} can be duplicated with the @ref{using} filter on the
5917: `splot` command, but @ref{mapping} may be more convenient if many data files are
5918: to be processed. However even if @ref{mapping} is used, @ref{using} may still be
5919: necessary if the data in the file are not in the required order.
5920:
5921: @ref{mapping} has no effect on @ref{plot}.
5922: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/world.html,Mapping Demos.}
5923:
5924: @node margin, missing, mapping, set-show
5925: @subsection margin
5926:
5927: @c ?commands set margin
5928: @c ?commands show margin
5929: @c ?set margin
5930: @c ?show margin
5931: @cindex margin
5932: @opindex margin
5933:
5934:
5935: The computed margins can be overridden by the @ref{margin} commands. @ref{margin} shows the current settings.
5936:
5937: Syntax:
5938: @example
5939: set bmargin @{<margin>@}
5940: set lmargin @{<margin>@}
5941: set rmargin @{<margin>@}
5942: set tmargin @{<margin>@}
5943: show margin
5944:
5945: @end example
5946:
5947: The units of <margin> are character heights or widths, as appropriate. A
5948: positive value defines the absolute size of the margin. A negative value
5949: (or none) causes `gnuplot` to revert to the computed value.
5950:
5951: Normally the margins of a plot are automatically calculated based on tics,
5952: tic labels, axis labels, the plot title, the timestamp and the size of the
5953: key if it is outside the borders. If, however, tics are attached to the
5954: axes (`set xtics axis`, for example), neither the tics themselves nor their
5955: labels will be included in either the margin calculation or the calculation
5956: of the positions of other text to be written in the margin. This can lead
5957: to tic labels overwriting other text if the axis is very close to the border.
5958:
5959: @node missing, multiplot, margin, set-show
5960: @subsection missing
5961:
5962: @c ?commands set missing
5963: @c ?set missing
5964: @cindex missing
5965: @opindex missing
5966:
5967:
5968: The @ref{missing} command allows you to tell `gnuplot` what character is
5969: used in a data file to denote missing data.
5970:
5971: Syntax:
5972: @example
5973: set missing @{"<character>"@}
5974: show missing
5975:
5976: @end example
5977:
5978: Example:
5979: @example
5980: set missing "?"
5981:
5982: @end example
5983:
5984: would mean that, when plotting a file containing
5985:
5986: @example
5987: 1 1
5988: 2 ?
5989: 3 2
5990:
5991: @end example
5992:
5993: the middle line would be ignored.
5994:
5995: There is no default character for @ref{missing}.
5996:
5997: @node multiplot, mx2tics, missing, set-show
5998: @subsection multiplot
5999:
6000: @c ?commands set multiplot
6001: @c ?commands set nomultiplot
6002: @c ?set multiplot
6003: @c ?set nomultiplot
6004: @cindex multiplot
6005: @opindex multiplot
6006:
6007:
6008: @cindex nomultiplot
6009:
6010: The command @ref{multiplot} places `gnuplot` in the multiplot mode, in which
6011: several plots are placed on the same page, window, or screen.
6012:
6013: Syntax:
6014: @example
6015: set multiplot
6016: set nomultiplot
6017:
6018: @end example
6019:
6020: For some terminals, no plot is displayed until the command `set nomultiplot`
6021: is given, which causes the entire page to be drawn and then returns `gnuplot`
6022: to its normal single-plot mode. For other terminals, each separate @ref{plot}
6023: command produces a plot, but the screen may not be cleared between plots.
6024:
6025: Any labels or arrows that have been defined will be drawn for each plot
6026: according to the current size and origin (unless their coordinates are
6027: defined in the `screen` system). Just about everything else that can be
6028: `set` is applied to each plot, too. If you want something to appear only
6029: once on the page, for instance a single time stamp, you'll need to put a `set
6030: time`/`set notime` pair around one of the @ref{plot}, `splot` or @ref{replot}
6031: commands within the @ref{multiplot}/`set nomultiplot` block.
6032:
6033: The commands @ref{origin} and @ref{size} must be used to correctly position
6034: each plot; see @ref{origin} and @ref{size} for details of their usage.
6035:
6036: Example:
6037: @example
6038: set size 0.7,0.7
6039: set origin 0.1,0.1
6040: set multiplot
6041: set size 0.4,0.4
6042: set origin 0.1,0.1
6043: plot sin(x)
6044: set size 0.2,0.2
6045: set origin 0.5,0.5
6046: plot cos(x)
6047: set nomultiplot
6048:
6049: @end example
6050:
6051: displays a plot of cos(x) stacked above a plot of sin(x). Note the initial
6052: @ref{size} and @ref{origin}. While these are not always required, their
6053: inclusion is recommended. Some terminal drivers require that bounding box
6054: information be available before any plots can be made, and the form given
6055: above guarantees that the bounding box will include the entire plot array
6056: rather than just the bounding box of the first plot.
6057:
6058: @ref{size} and @ref{origin} refer to the entire plotting area used for each
6059: plot. If you want to have the axes themselves line up, you can guarantee
6060: that the margins are the same size with the @ref{margin} commands. See
6061: @ref{margin} for their use. Note that the margin settings are absolute,
6062: in character units, so the appearance of the graph in the remaining space
6063: will depend on the screen size of the display device, e.g., perhaps quite
6064: different on a video display and a printer.
6065: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/multiplt.html,See demo. }
6066:
6067: @node mx2tics, mxtics, multiplot, set-show
6068: @subsection mx2tics
6069:
6070: @c ?commands set mx2tics
6071: @c ?commands set nomx2tics
6072: @c ?commands show mx2tics
6073: @c ?set mx2tics
6074: @c ?set nomx2tics
6075: @c ?show mx2tics
6076: @cindex mx2tics
6077: @opindex mx2tics
6078:
6079:
6080: @cindex nomx2tics
6081:
6082: Minor tic marks along the x2 (top) axis are controlled by @ref{mx2tics}.
6083: Please see @ref{mxtics}.
6084:
6085: @node mxtics, my2tics, mx2tics, set-show
6086: @subsection mxtics
6087:
6088: @c ?commands set mxtics
6089: @c ?commands set nomxtics
6090: @c ?commands show mxtics
6091: @c ?set mxtics
6092: @c ?set nomxtics
6093: @c ?show mxtics
6094: @cindex mxtics
6095: @opindex mxtics
6096:
6097:
6098: @cindex nomxtics
6099:
6100: Minor tic marks along the x axis are controlled by @ref{mxtics}. They can be
6101: turned off with `set nomxtics`. Similar commands control minor tics along
6102: the other axes.
6103:
6104: Syntax:
6105: @example
6106: set mxtics @{<freq> | default@}
6107: set nomxtics
6108: show mxtics
6109:
6110: @end example
6111:
6112: The same syntax applies to @ref{mytics}, @ref{mztics}, @ref{mx2tics} and @ref{my2tics}.
6113:
6114: <freq> is the number of sub-intervals (NOT the number of minor tics) between
6115: major tics (ten is the default for a linear axis, so there are nine minor
6116: tics between major tics). Selecting `default` will return the number of minor
6117: ticks to its default value.
6118:
6119: If the axis is logarithmic, the number of sub-intervals will be set to a
6120: reasonable number by default (based upon the length of a decade). This will
6121: be overridden if <freq> is given. However the usual minor tics (2, 3, ...,
6122: 8, 9 between 1 and 10, for example) are obtained by setting <freq> to 10,
6123: even though there are but nine sub-intervals.
6124:
6125: Minor tics can be used only with uniformly spaced major tics. Since major
6126: tics can be placed arbitrarily by `set @{x|x2|y|y2|z@}tics`, minor tics cannot
6127: be used if major tics are explicitly `set`.
6128:
6129: By default, minor tics are off for linear axes and on for logarithmic axes.
6130: They inherit the settings for `axis|border` and `@{no@}mirror` specified for
6131: the major tics. Please see @ref{xtics} for information about these.
6132:
6133: @node my2tics, mytics, mxtics, set-show
6134: @subsection my2tics
6135:
6136: @c ?commands set my2tics
6137: @c ?commands set nomy2tics
6138: @c ?commands show my2tics
6139: @c ?set my2tics
6140: @c ?set nomy2tics
6141: @c ?show my2tics
6142: @cindex my2tics
6143: @opindex my2tics
6144:
6145:
6146: @cindex nomy2tics
6147:
6148: Minor tic marks along the y2 (right-hand) axis are controlled by @ref{my2tics}. Please see @ref{mxtics}.
6149:
6150: @node mytics, mztics, my2tics, set-show
6151: @subsection mytics
6152:
6153: @c ?commands set mytics
6154: @c ?commands set nomytics
6155: @c ?commands show mytics
6156: @c ?set mytics
6157: @c ?set nomytics
6158: @c ?show mytics
6159: @cindex mytics
6160: @opindex mytics
6161:
6162:
6163: @cindex nomytics
6164:
6165: Minor tic marks along the y axis are controlled by @ref{mytics}. Please
6166: see @ref{mxtics}.
6167:
6168: @node mztics, offsets, mytics, set-show
6169: @subsection mztics
6170:
6171: @c ?commands set mztics
6172: @c ?commands set nomztics
6173: @c ?commands show mztics
6174: @c ?set mztics
6175: @c ?set nomztics
6176: @c ?show mztics
6177: @cindex mztics
6178: @opindex mztics
6179:
6180:
6181: @cindex nomztics
6182:
6183: Minor tic marks along the z axis are controlled by @ref{mztics}. Please
6184: see @ref{mxtics}.
6185:
6186: @node offsets, origin, mztics, set-show
6187: @subsection offsets
6188:
6189: @c ?commands set offsets
6190: @c ?commands set nooffsets
6191: @c ?commands show offsets
6192: @c ?set offsets
6193: @c ?set nooffsets
6194: @c ?show offsets
6195: @cindex offsets
6196: @opindex offsets
6197:
6198:
6199: @cindex nooffsets
6200:
6201: Offsets provide a mechanism to put a boundary around the data inside of an
6202: autoscaled graph.
6203:
6204: Syntax:
6205: @example
6206: set offsets <left>, <right>, <top>, <bottom>
6207: set nooffsets
6208: show offsets
6209:
6210: @end example
6211:
6212: Each offset may be a constant or an expression. Each defaults to 0. Left
6213: and right offsets are given in units of the x axis, top and bottom offsets in
6214: units of the y axis. A positive offset expands the graph in the specified
6215: direction, e.g., a positive bottom offset makes ymin more negative. Negative
6216: offsets, while permitted, can have unexpected interactions with autoscaling
6217: and clipping.
6218:
6219: Offsets are ignored in `splot`s.
6220:
6221: Example:
6222: @example
6223: set offsets 0, 0, 2, 2
6224: plot sin(x)
6225:
6226: @end example
6227:
6228: This graph of sin(x) will have a y range [-3:3] because the function
6229: will be autoscaled to [-1:1] and the vertical offsets are each two.
6230:
6231: @node origin, output, offsets, set-show
6232: @subsection origin
6233:
6234: @c ?commands set origin
6235: @c ?commands show origin
6236: @c ?set origin
6237: @c ?show origin
6238: @cindex origin
6239: @opindex origin
6240:
6241:
6242: The @ref{origin} command is used to specify the origin of a plotting surface
6243: (i.e., the graph and its margins) on the screen. The coordinates are given
6244: in the `screen` coordinate system (see `coordinates` for information about
6245: this system).
6246:
6247: Syntax:
6248: @example
6249: set origin <x-origin>,<y-origin>
6250:
6251: @end example
6252:
6253: @node output, parametric_, origin, set-show
6254: @subsection output
6255:
6256: @c ?commands set output
6257: @c ?commands show output
6258: @c ?set output
6259: @c ?show output
6260: @cindex output
6261: @opindex output
6262:
6263:
6264: By default, screens are displayed to the standard output. The @ref{output}
6265: command redirects the display to the specified file or device.
6266:
6267: Syntax:
6268: @example
6269: set output @{"<filename>"@}
6270: show output
6271:
6272: @end example
6273:
6274: The filename must be enclosed in quotes. If the filename is omitted, any
6275: output file opened by a previous invocation of @ref{output} will be closed
6276: and new output will be sent to STDOUT. (If you give the command `set output
6277: "STDOUT"`, your output may be sent to a file named "STDOUT"! ["May be", not
6278: "will be", because some terminals, like `x11`, ignore @ref{output}.])
6279:
6280: MSDOS users should note that the \ character has special significance in
6281: double-quoted strings, so single-quotes should be used for filenames in
6282: different directories.
6283:
6284: When both @ref{terminal} and @ref{output} are used together, it is safest to
6285: give @ref{terminal} first, because some terminals set a flag which is needed
6286: in some operating systems. This would be the case, for example, if the
6287: operating system needs to know whether or not a file is to be formatted in
6288: order to open it properly.
6289:
6290: On machines with popen functions (Unix), output can be piped through a shell
6291: command if the first non-whitespace character of the filename is '|'.
6292: For instance,
6293:
6294: @example
6295: set output "|lpr -Plaser filename"
6296: set output "|lp -dlaser filename"
6297:
6298: @end example
6299:
6300: On MSDOS machines, `set output "PRN"` will direct the output to the default
6301: printer. On VMS, output can be sent directly to any spooled device. It is
6302: also possible to send the output to DECnet transparent tasks, which allows
6303: some flexibility.
6304:
6305: @node parametric_, pointsize, output, set-show
6306: @subsection parametric
6307:
6308: @c ?commands set parametric
6309: @c ?commands set noparametric
6310: @c ?commands show parametric
6311: @c ?set parametric
6312: @c ?set noparametric
6313: @c ?show parametric
6314: @cindex parametric
6315: @opindex parametric
6316:
6317:
6318: @cindex noparametric
6319:
6320: The `set parametric` command changes the meaning of @ref{plot} (`splot`) from
6321: normal functions to parametric functions. The command `set noparametric`
6322: restores the plotting style to normal, single-valued expression plotting.
6323:
6324: Syntax:
6325: @example
6326: set parametric
6327: set noparametric
6328: show parametric
6329:
6330: @end example
6331:
6332: For 2-d plotting, a parametric function is determined by a pair of parametric
6333: functions operating on a parameter. An example of a 2-d parametric function
6334: would be `plot sin(t),cos(t)`, which draws a circle (if the aspect ratio is
6335: set correctly---see @ref{size}). `gnuplot` will display an error message if
6336: both functions are not provided for a parametric @ref{plot}.
6337:
6338: For 3-d plotting, the surface is described as x=f(u,v), y=g(u,v), z=h(u,v).
6339: Therefore a triplet of functions is required. An example of a 3-d parametric
6340: function would be `cos(u)*cos(v),cos(u)*sin(v),sin(u)`, which draws a sphere.
6341: `gnuplot` will display an error message if all three functions are not
6342: provided for a parametric `splot`.
6343:
6344: The total set of possible plots is a superset of the simple f(x) style plots,
6345: since the two functions can describe the x and y values to be computed
6346: separately. In fact, plots of the type t,f(t) are equivalent to those
6347: produced with f(x) because the x values are computed using the identity
6348: function. Similarly, 3-d plots of the type u,v,f(u,v) are equivalent to
6349: f(x,y).
6350:
6351: Note that the order the parametric functions are specified is xfunction,
6352: yfunction (and zfunction) and that each operates over the common parametric
6353: domain.
6354:
6355: Also, the `set parametric` function implies a new range of values. Whereas
6356: the normal f(x) and f(x,y) style plotting assume an xrange and yrange (and
6357: zrange), the parametric mode additionally specifies a trange, urange, and
6358: vrange. These ranges may be set directly with @ref{trange}, @ref{urange},
6359: and @ref{vrange}, or by specifying the range on the @ref{plot} or `splot`
6360: commands. Currently the default range for these parametric variables is
6361: [-5:5]. Setting the ranges to something more meaningful is expected.
6362:
6363: @node pointsize, polar, parametric_, set-show
6364: @subsection pointsize
6365:
6366: @c ?commands set pointsize
6367: @c ?commands show pointsize
6368: @c ?set pointsize
6369: @c ?show pointsize
6370: @cindex pointsize
6371: @opindex pointsize
6372:
6373:
6374: The @ref{pointsize} command scales the size of the points used in plots.
6375:
6376: Syntax:
6377: @example
6378: set pointsize <multiplier>
6379: show pointsize
6380:
6381: @end example
6382:
6383: The default is a multiplier of 1.0. Larger pointsizes may be useful to
6384: make points more visible in bitmapped graphics.
6385:
6386: The pointsize of a single plot may be changed on the @ref{plot} command. See
6387: @ref{with} for details.
6388:
6389: Please note that the pointsize setting is not supported by all terminal
6390: types.
6391:
6392: @node polar, rmargin, pointsize, set-show
6393: @subsection polar
6394:
6395: @c ?commands set polar
6396: @c ?commands set nopolar
6397: @c ?commands show polar
6398: @c ?set polar
6399: @c ?set nopolar
6400: @c ?show polar
6401: @cindex polar
6402: @opindex polar
6403:
6404:
6405: @cindex nopolar
6406:
6407: The `set polar` command changes the meaning of the plot from rectangular
6408: coordinates to polar coordinates.
6409:
6410: Syntax:
6411: @example
6412: set polar
6413: set nopolar
6414: show polar
6415:
6416: @end example
6417:
6418: There have been changes made to polar mode in version 3.7, so that scripts
6419: for `gnuplot` versions 3.5 and earlier will require modification. The main
6420: change is that the dummy variable t is used for the angle so that the x and
6421: y ranges can be controlled independently. Other changes are:
6422: 1) tics are no longer put along the zero axes automatically
6423: ---use `set xtics axis nomirror`; `set ytics axis nomirror`;
6424: 2) the grid, if selected, is not automatically polar
6425: ---use `set grid polar`;
6426: 3) the grid is not labelled with angles
6427: ---use @ref{label} as necessary.
6428:
6429: In polar coordinates, the dummy variable (t) is an angle. The default range
6430: of t is [0:2*pi], or, if degree units have been selected, to [0:360] (see
6431: @ref{angles}).
6432:
6433: The command `set nopolar` changes the meaning of the plot back to the default
6434: rectangular coordinate system.
6435:
6436: The `set polar` command is not supported for `splot`s. See the @ref{mapping}
6437: command for similar functionality for `splot`s.
6438:
6439: While in polar coordinates the meaning of an expression in t is really
6440: r = f(t), where t is an angle of rotation. The trange controls the domain
6441: (the angle) of the function, and the x and y ranges control the range of the
6442: graph in the x and y directions. Each of these ranges, as well as the
6443: rrange, may be autoscaled or set explicitly. See @ref{xrange} for details
6444: of all the `set range` commands.
6445:
6446: Example:
6447: @example
6448: set polar
6449: plot t*sin(t)
6450: plot [-2*pi:2*pi] [-3:3] [-3:3] t*sin(t)
6451:
6452: @end example
6453:
6454: The first @ref{plot} uses the default polar angular domain of 0 to 2*pi. The
6455: radius and the size of the graph are scaled automatically. The second @ref{plot}
6456: expands the domain, and restricts the size of the graph to [-3:3] in both
6457: directions.
6458:
6459: You may want to `set size square` to have `gnuplot` try to make the aspect
6460: ratio equal to unity, so that circles look circular.
6461: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/polar.html,Polar demos }
6462: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/poldat.html,Polar Data Plot. }
6463:
6464: @node rmargin, rrange, polar, set-show
6465: @subsection rmargin
6466:
6467: @c ?commands set rmargin
6468: @c ?set rmargin
6469: @cindex rmargin
6470: @opindex rmargin
6471:
6472:
6473: The command @ref{rmargin} sets the size of the right margin. Please see
6474: @ref{margin} for details.
6475:
6476: @node rrange, samples, rmargin, set-show
6477: @subsection rrange
6478:
6479: @c ?commands set rrange
6480: @c ?commands show rrange
6481: @c ?set rrange
6482: @c ?show rrange
6483: @cindex rrange
6484: @opindex rrange
6485:
6486:
6487: The @ref{rrange} command sets the range of the radial coordinate for a
6488: graph in polar mode. Please see @ref{xrange} for details.
6489:
6490: @node samples, size, rrange, set-show
6491: @subsection samples
6492:
6493: @c ?commands set samples
6494: @c ?commands show samples
6495: @c ?set samples
6496: @c ?show samples
6497: @cindex samples
6498: @opindex samples
6499:
6500:
6501: The sampling rate of functions, or for interpolating data, may be changed
6502: by the @ref{samples} command.
6503:
6504: Syntax:
6505: @example
6506: set samples <samples_1> @{,<samples_2>@}
6507: show samples
6508:
6509: @end example
6510:
6511: By default, sampling is set to 100 points. A higher sampling rate will
6512: produce more accurate plots, but will take longer. This parameter has no
6513: effect on data file plotting unless one of the interpolation/approximation
6514: options is used. See @ref{smooth} re 2-d data and @ref{cntrparam} and
6515: @ref{dgrid3d} re 3-d data.
6516:
6517: When a 2-d graph is being done, only the value of <samples_1> is relevant.
6518:
6519: When a surface plot is being done without the removal of hidden lines, the
6520: value of samples specifies the number of samples that are to be evaluated for
6521: the isolines. Each iso-v line will have <sample_1> samples and each iso-u
6522: line will have <sample_2> samples. If you only specify <samples_1>,
6523: <samples_2> will be set to the same value as <samples_1>. See also @ref{isosamples}.
6524:
6525: @node size, style, samples, set-show
6526: @subsection size
6527:
6528: @c ?commands set size
6529: @c ?commands show size
6530: @c ?set size
6531: @c ?show size
6532: @cindex size
6533: @opindex size
6534:
6535:
6536: The @ref{size} command scales the displayed size of the plot.
6537:
6538: Syntax:
6539: @example
6540: set size @{@{no@}square | ratio <r> | noratio@} @{<xscale>,<yscale>@}
6541: show size
6542:
6543: @end example
6544:
6545: The <xscale> and <yscale> values are the scaling factors for the size of the
6546: plot, which includes the graph and the margins.
6547:
6548: `ratio` causes `gnuplot` to try to create a graph with an aspect ratio of <r>
6549: (the ratio of the y-axis length to the x-axis length) within the portion of
6550: the plot specified by <xscale> and <yscale>.
6551:
6552: The meaning of a negative value for <r> is different. If <r>=-1, gnuplot
6553: tries to set the scales so that the unit has the same length on both the x
6554: and y axes (suitable for geographical data, for instance). If <r>=-2, the
6555: unit on y has twice the length of the unit on x, and so on.
6556:
6557: The success of `gnuplot` in producing the requested aspect ratio depends on
6558: the terminal selected. The graph area will be the largest rectangle of
6559: aspect ratio <r> that will fit into the specified portion of the output
6560: (leaving adequate margins, of course).
6561:
6562: `square` is a synonym for `ratio 1`.
6563:
6564: Both `noratio` and `nosquare` return the graph to the default aspect ratio
6565: of the terminal, but do not return <xscale> or <yscale> to their default
6566: values (1.0).
6567:
6568: `ratio` and `square` have no effect on 3-d plots.
6569:
6570: @ref{size} is relative to the default size, which differs from terminal to
6571: terminal. Since `gnuplot` fills as much of the available plotting area as
6572: possible by default, it is safer to use @ref{size} to decrease the size of
6573: a plot than to increase it. See @ref{terminal} for the default sizes.
6574:
6575: On some terminals, changing the size of the plot will result in text being
6576: misplaced.
6577:
6578: Examples:
6579:
6580: To set the size to normal size use:
6581: @example
6582: set size 1,1
6583:
6584: @end example
6585:
6586: To make the graph half size and square use:
6587: @example
6588: set size square 0.5,0.5
6589:
6590: @end example
6591:
6592: To make the graph twice as high as wide use:
6593: @example
6594: set size ratio 2
6595:
6596: @end example
6597:
6598: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/airfoil.html,See demo. }
6599:
6600: @node style, surface, size, set-show
6601: @subsection style
6602:
6603: @c ?commands set function style
6604: @c ?commands show function style
6605: @c ?commands set data style
6606: @c ?commands show data style
6607: @c ?set function style
6608: @c ?show function style
6609: @c ?set data style
6610: @c ?show data style
6611: @c ?set style
6612: @c ?show style
6613: Default styles are chosen with the @ref{style} and @ref{style}
6614: commands. See @ref{with} for information about how to override the default
6615: plotting style for individual functions and data sets.
6616:
6617: Syntax:
6618: @example
6619: set function style <style>
6620: set data style <style>
6621: show function style
6622: show data style
6623:
6624: @end example
6625:
6626: The types used for all line and point styles (i.e., solid, dash-dot, color,
6627: etc. for lines; circles, squares, crosses, etc. for points) will be either
6628: those specified on the @ref{plot} or `splot` command or will be chosen
6629: sequentially from the types available to the terminal in use. Use the
6630: command @ref{test} to see what is available.
6631:
6632: None of the styles requiring more than two columns of information (e.g.,
6633: @ref{errorbars}) can be used with `splot`s or function @ref{plot}s. Neither @ref{boxes}
6634: nor any of the @ref{steps} styles can be used with `splot`s. If an inappropriate
6635: style is specified, it will be changed to `points`.
6636:
6637: For 2-d data with more than two columns, `gnuplot` is picky about the allowed
6638: `errorbar` styles. The @ref{using} option on the @ref{plot} command can be used to
6639: set up the correct columns for the style you want. (In this discussion,
6640: "column" will be used to refer both to a column in the data file and an entry
6641: in the @ref{using} list.)
6642:
6643: For three columns, only @ref{xerrorbars}, @ref{yerrorbars} (or @ref{errorbars}), @ref{boxes},
6644: and @ref{boxerrorbars} are allowed. If another plot style is used, the style
6645: will be changed to @ref{yerrorbars}. The @ref{boxerrorbars} style will calculate the
6646: boxwidth automatically.
6647:
6648: For four columns, only @ref{xerrorbars}, @ref{yerrorbars} (or @ref{errorbars}),
6649: @ref{xyerrorbars}, @ref{boxxyerrorbars}, and @ref{boxerrorbars} are allowed. An illegal
6650: style will be changed to @ref{yerrorbars}.
6651:
6652: Five-column data allow only the @ref{boxerrorbars}, @ref{financebars}, and
6653: @ref{candlesticks} styles. (The last two of these are primarily used for plots
6654: of financial prices.) An illegal style will be changed to @ref{boxerrorbars}
6655: before plotting.
6656:
6657: Six- and seven-column data only allow the @ref{xyerrorbars} and @ref{boxxyerrorbars}
6658: styles. Illegal styles will be changed to @ref{xyerrorbars} before plotting.
6659:
6660: For more information about error bars, please see @ref{errorbars}.
6661:
6662: @menu
6663: * boxerrorbars::
6664: * boxes::
6665: * boxxyerrorbars::
6666: * candlesticks::
6667: * dots::
6668: * financebars::
6669: * fsteps::
6670: * histeps::
6671: * impulses::
6672: * lines::
6673: * linespoints::
6674: * points::
6675: * steps::
6676: * vector::
6677: * xerrorbars::
6678: * xyerrorbars::
6679: * yerrorbars::
6680: @end menu
6681:
6682: @node boxerrorbars, boxes, style, style
6683: @subsubsection boxerrorbars
6684:
6685: @c ?commands set style boxerrorbars
6686: @c ?set style boxerrorbars
6687: @c ?style boxerrorbars
6688: @cindex boxerrorbars
6689:
6690: The @ref{boxerrorbars} style is only relevant to 2-d data plotting. It is a
6691: combination of the @ref{boxes} and @ref{yerrorbars} styles. The boxwidth will come
6692: from the fourth column if the y errors are in the form of "ydelta" and the
6693: boxwidth was not previously set equal to -2.0 (`set boxwidth -2.0`) or from
6694: the fifth column if the y errors are in the form of "ylow yhigh". The
6695: special case `boxwidth = -2.0` is for four-column data with y errors in the
6696: form "ylow yhigh". In this case the boxwidth will be calculated so that each
6697: box touches the adjacent boxes. The width will also be calculated in cases
6698: where three-column data are used.
6699:
6700: The box height is determined from the y error in the same way as it is for
6701: the @ref{yerrorbars} style---either from y-ydelta to y+ydelta or from ylow to
6702: yhigh, depending on how many data columns are provided.
6703: @uref{http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html,See Demo. }
6704:
6705: @node boxes, boxxyerrorbars, boxerrorbars, style
6706: @subsubsection boxes
6707:
6708: @c ?commands set style boxes
6709: @c ?commands set style bargraph
6710: @c ?set style boxes
6711: @c ?set style bargraph
6712: @c ?style boxes
6713: @c ?style bargraph
6714: @cindex boxes
6715:
6716: @cindex bargraph
6717:
6718: The @ref{boxes} style is only relevant to 2-d plotting. It draws a box centered
6719: about the given x coordinate from the x axis (not the graph border) to the
6720: given y coordinate. The width of the box is obtained in one of three ways.
6721: If it is a data plot and the data file has a third column, this will be used
6722: to set the width of the box. If not, if a width has been set using the @ref{boxwidth} command, this will be used. If neither of these is available, the
6723: width of each box will be calculated automatically so that it touches the
6724: adjacent boxes.
6725:
6726: @node boxxyerrorbars, candlesticks, boxes, style
6727: @subsubsection boxxyerrorbars
6728:
6729: @c ?commands set style boxxyerrorbars
6730: @c ?set style boxxyerrorbars
6731: @c ?style boxxyerrorbars
6732: @cindex boxxyerrorbars
6733:
6734: The @ref{boxxyerrorbars} style is only relevant to 2-d data plotting. It is a
6735: combination of the @ref{boxes} and @ref{xyerrorbars} styles.
6736:
6737: The box width and height are determined from the x and y errors in the same
6738: way as they are for the @ref{xyerrorbars} style---either from xlow to xhigh and
6739: from ylow to yhigh, or from x-xdelta to x+xdelta and from y-ydelta to
6740: y+ydelta , depending on how many data columns are provided.
6741:
6742: @node candlesticks, dots, boxxyerrorbars, style
6743: @subsubsection candlesticks
6744:
6745: @c ?commands set style candlesticks
6746: @c ?set style candlesticks
6747: @c ?style candlesticks
6748: @cindex candlesticks
6749:
6750: The @ref{candlesticks} style is only relevant for 2-d data plotting of financial
6751: data. Five columns of data are required; in order, these should be the x
6752: coordinate (most likely a date) and the opening, low, high, and closing
6753: prices. The symbol is an open rectangle, centered horizontally at the x
6754: coordinate and limited vertically by the opening and closing prices. A
6755: vertical line segment at the x coordinate extends up from the top of the
6756: rectangle to the high price and another down to the low. The width of the
6757: rectangle may be changed by @ref{bar}. The symbol will be unchanged if the
6758: low and high prices are interchanged or if the opening and closing prices
6759: are interchanged. See @ref{bar} and @ref{financebars}.
6760: @uref{http://www.nas.nasa.gov/~woo/gnuplot/finance/finance.html,See demos.}
6761:
6762: @node dots, financebars, candlesticks, style
6763: @subsubsection dots
6764:
6765: @c ?commands set style dots
6766: @c ?set style dots
6767: @c ?style dots
6768: @cindex dots
6769:
6770: The @ref{dots} style plots a tiny dot at each point; this is useful for scatter
6771: plots with many points.
6772:
6773: @node financebars, fsteps, dots, style
6774: @subsubsection financebars
6775:
6776: @c ?commands set style financebars
6777: @c ?set style financebars
6778: @c ?style financebars
6779: @cindex financebars
6780:
6781: The @ref{financebars} style is only relevant for 2-d data plotting of financial
6782: data. Five columns of data are required; in order, these should be the x
6783: coordinate (most likely a date) and the opening, low, high, and closing
6784: prices. The symbol is a vertical line segment, located horizontally at the x
6785: coordinate and limited vertically by the high and low prices. A horizontal
6786: tic on the left marks the opening price and one on the right marks the
6787: closing price. The length of these tics may be changed by @ref{bar}. The
6788: symbol will be unchanged if the high and low prices are interchanged. See
6789: @ref{bar} and @ref{candlesticks}.
6790: @uref{http://www.nas.nasa.gov/~woo/gnuplot/finance/finance.html,See demos.}
6791:
6792: @node fsteps, histeps, financebars, style
6793: @subsubsection fsteps
6794:
6795: @c ?commands set style fsteps
6796: @c ?set style fsteps
6797: @c ?style fsteps
6798: @cindex fsteps
6799:
6800: The @ref{fsteps} style is only relevant to 2-d plotting. It connects consecutive
6801: points with two line segments: the first from (x1,y1) to (x1,y2) and the
6802: second from (x1,y2) to (x2,y2).
6803: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/steps.html,See demo. }
6804:
6805: @node histeps, impulses, fsteps, style
6806: @subsubsection histeps
6807:
6808: @c ?commands set style histeps
6809: @c ?set style histeps
6810: @c ?style histeps
6811: @cindex histeps
6812:
6813: The @ref{histeps} style is only relevant to 2-d plotting. It is intended for
6814: plotting histograms. Y-values are assumed to be centered at the x-values;
6815: the point at x1 is represented as a horizontal line from ((x0+x1)/2,y1) to
6816: ((x1+x2)/2,y1). The lines representing the end points are extended so that
6817: the step is centered on at x. Adjacent points are connected by a vertical
6818: line at their average x, that is, from ((x1+x2)/2,y1) to ((x1+x2)/2,y2).
6819:
6820: If @ref{autoscale} is in effect, it selects the xrange from the data rather than
6821: the steps, so the end points will appear only half as wide as the others.
6822: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/steps.html,See demo. }
6823:
6824: @ref{histeps} is only a plotting style; `gnuplot` does not have the ability to
6825: create bins and determine their population from some data set.
6826:
6827: @node impulses, lines, histeps, style
6828: @subsubsection impulses
6829:
6830: @c ?commands set style impulses
6831: @c ?set style impulses
6832: @c ?style impulses
6833: @cindex impulses
6834:
6835: The @ref{impulses} style displays a vertical line from the x axis (not the graph
6836: border), or from the grid base for `splot`, to each point.
6837:
6838: @node lines, linespoints, impulses, style
6839: @subsubsection lines
6840:
6841: @c ?commands set style lines
6842: @c ?set style lines
6843: @c ?style lines
6844: @cindex lines
6845:
6846: The `lines` style connects adjacent points with straight line segments.
6847:
6848: @node linespoints, points, lines, style
6849: @subsubsection linespoints
6850:
6851: @c ?commands set style linespoints
6852: @c ?commands set style lp
6853: @c ?set style linespoints
6854: @c ?set style lp
6855: @c ?style linespoints
6856: @c ?style lp
6857: @cindex linespoints
6858:
6859: @cindex lp
6860:
6861: The @ref{linespoints} style does both `lines` and `points`, that is, it draws a
6862: small symbol at each point and then connects adjacent points with straight
6863: line segments. The command @ref{pointsize} may be used to change the size of
6864: the points. See @ref{pointsize} for its usage.
6865:
6866: @ref{linespoints} may be abbreviated `lp`.
6867:
6868: @node points, steps, linespoints, style
6869: @subsubsection points
6870:
6871: @c ?commands set style points
6872: @c ?set style points
6873: @c ?style points
6874: @cindex points
6875:
6876: The `points` style displays a small symbol at each point. The command @ref{pointsize} may be used to change the size of the points. See @ref{pointsize}
6877: for its usage.
6878:
6879: @node steps, vector, points, style
6880: @subsubsection steps
6881:
6882: @c ?commands set style steps
6883: @c ?set style steps
6884: @c ?style steps
6885: @cindex steps
6886:
6887: The @ref{steps} style is only relevant to 2-d plotting. It connects consecutive
6888: points with two line segments: the first from (x1,y1) to (x2,y1) and the
6889: second from (x2,y1) to (x2,y2).
6890: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/steps.html,See demo. }
6891:
6892: @node vector, xerrorbars, steps, style
6893: @subsubsection vector
6894:
6895: @c ?commands set style vector
6896: @c ?set style vector
6897: @c ?style vector
6898: @cindex vector
6899:
6900: The @ref{vector} style draws a vector from (x,y) to (x+xdelta,y+ydelta). Thus
6901: it requires four columns of data. It also draws a small arrowhead at the
6902: end of the vector.
6903:
6904: The @ref{vector} style is still experimental: it doesn't get clipped properly
6905: and other things may also be wrong with it. Use it at your own risk.
6906:
6907: @node xerrorbars, xyerrorbars, vector, style
6908: @subsubsection xerrorbars
6909:
6910: @c ?commands set style xerrorbars
6911: @c ?set style xerrorbars
6912: @c ?style xerrorbars
6913: @cindex xerrorbars
6914:
6915: The @ref{xerrorbars} style is only relevant to 2-d data plots. @ref{xerrorbars} is
6916: like @ref{dots}, except that a horizontal error bar is also drawn. At each point
6917: (x,y), a line is drawn from (xlow,y) to (xhigh,y) or from (x-xdelta,y) to
6918: (x+xdelta,y), depending on how many data columns are provided. A tic mark
6919: is placed at the ends of the error bar (unless @ref{bar} is used---see @ref{bar} for details).
6920:
6921: @node xyerrorbars, yerrorbars, xerrorbars, style
6922: @subsubsection xyerrorbars
6923:
6924: @c ?commands set style xyerrorbars
6925: @c ?set style xyerrorbars
6926: @c ?style xyerrorbars
6927: @cindex xyerrorbars
6928:
6929: The @ref{xyerrorbars} style is only relevant to 2-d data plots. @ref{xyerrorbars} is
6930: like @ref{dots}, except that horizontal and vertical error bars are also drawn.
6931: At each point (x,y), lines are drawn from (x,y-ydelta) to (x,y+ydelta) and
6932: from (x-xdelta,y) to (x+xdelta,y) or from (x,ylow) to (x,yhigh) and from
6933: (xlow,y) to (xhigh,y), depending upon the number of data columns provided. A
6934: tic mark is placed at the ends of the error bar (unless @ref{bar} is
6935: used---see @ref{bar} for details).
6936:
6937: If data are provided in an unsupported mixed form, the @ref{using} filter on the
6938: @ref{plot} command should be used to set up the appropriate form. For example,
6939: if the data are of the form (x,y,xdelta,ylow,yhigh), then you can use
6940:
6941: @example
6942: plot 'data' using 1:2:($1-$3),($1+$3),4,5 with xyerrorbars
6943:
6944: @end example
6945:
6946: @node yerrorbars, , xyerrorbars, style
6947: @subsubsection yerrorbars
6948:
6949: @c ?commands set style yerrorbars
6950: @c ?commands set style errorbars
6951: @c ?set style yerrorbars
6952: @c ?set style errorbars
6953: @c ?style yerrorbars
6954: @c ?style errorbars
6955: @cindex yerrorbars
6956:
6957: @cindex errorbars
6958:
6959: The @ref{yerrorbars} (or @ref{errorbars}) style is only relevant to 2-d data plots.
6960: @ref{yerrorbars} is like @ref{dots}, except that a vertical error bar is also drawn.
6961: At each point (x,y), a line is drawn from (x,y-ydelta) to (x,y+ydelta) or
6962: from (x,ylow) to (x,yhigh), depending on how many data columns are provided.
6963: A tic mark is placed at the ends of the error bar (unless @ref{bar} is
6964: used---see @ref{bar} for details).
6965: @uref{http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html,See demo. }
6966:
6967: @node surface, terminal, style, set-show
6968: @subsection surface
6969:
6970: @c ?commands set surface
6971: @c ?commands set nosurface
6972: @c ?commands show surface
6973: @c ?set surface
6974: @c ?set nosurface
6975: @c ?show surface
6976: @cindex surface
6977: @opindex surface
6978:
6979:
6980: @cindex nosurface
6981:
6982: The command @ref{surface} controls the display of surfaces by `splot`.
6983:
6984: Syntax:
6985: @example
6986: set surface
6987: set nosurface
6988: show surface
6989:
6990: @end example
6991:
6992: The surface is drawn with the style specifed by @ref{with}, or else the
6993: appropriate style, data or function.
6994:
6995: Whenever `set nosurface` is issued, `splot` will not draw points or lines
6996: corresponding to the function or data file points. Contours may be still be
6997: drawn on the surface, depending on the @ref{contour} option. `set nosurface;
6998: set contour base` is useful for displaying contours on the grid base. See
6999: also @ref{contour}.
7000: @c ^ <h2> Terminal Types </h2>
7001:
7002: @node terminal, tics, surface, set-show
7003: @subsection terminal
7004:
7005: @c ?commands set terminal
7006: @c ?commands show terminal
7007: @c ?set terminal
7008: @c ?set term
7009: @c ?show terminal
7010: @cindex terminal
7011: @opindex terminal
7012:
7013:
7014: @cindex term
7015:
7016: `gnuplot` supports many different graphics devices. Use @ref{terminal} to
7017: tell `gnuplot` what kind of output to generate. Use @ref{output} to redirect
7018: that output to a file or device.
7019:
7020: Syntax:
7021: @example
7022: set terminal @{<terminal-type>@}
7023: show terminal
7024:
7025: @end example
7026:
7027: If <terminal-type> is omitted, `gnuplot` will list the available terminal
7028: types. <terminal-type> may be abbreviated.
7029:
7030: If both @ref{terminal} and @ref{output} are used together, it is safest to
7031: give @ref{terminal} first, because some terminals set a flag which is needed
7032: in some operating systems.
7033:
7034: Several terminals have additional options. For example, see `dumb`,
7035: `iris4d`, `hpljii` or `postscript`.
7036:
7037: This document may describe drivers that are not available to you because they
7038: were not installed, or it may not describe all the drivers that are available
7039: to you, depending on its output format.
7040: @@c <4 -- all terminal stuff is pulled from the .trm files
7041:
7042: @menu
7043: * aifm::
7044: * cgm::
7045: * corel::
7046: * dumb::
7047: * dxf::
7048: * eepic::
7049: * epson-180dpi::
7050: * fig::
7051: * gif::
7052: * gpic::
7053: * hp2623a::
7054: * hp2648::
7055: * hp500c::
7056: * hpgl::
7057: * hpljii::
7058: * hppj::
7059: * imagen::
7060: * latex::
7061: * mf::
7062: * mif::
7063: * pbm::
7064: * png::
7065: * postscript::
7066: * pslatex_and_pstex::
7067: * pstricks::
7068: * qms::
7069: * regis::
7070: * sun::
7071: * tek410x::
7072: * table::
7073: * tek40::
7074: * texdraw::
7075: * tgif::
7076: * tkcanvas::
7077: * tpic::
7078: * x11::
7079: * xlib::
7080: @end menu
7081:
7082: @node aifm, cgm, terminal, terminal
7083: @subsubsection aifm
7084:
7085: @c ?commands set terminal aifm
7086: @c ?set terminal aifm
7087: @c ?set term aifm
7088: @c ?terminal aifm
7089: @c ?term aifm
7090: @cindex aifm
7091: @tmindex aifm
7092:
7093:
7094: Several options may be set in `aifm`---the Adobe Illustrator 3.0+ driver.
7095:
7096: Syntax:
7097: @example
7098: set terminal aifm @{<color>@} @{"<fontname>"@} @{<fontsize>@}
7099:
7100: @end example
7101:
7102: <color> is either `color` or `monochrome`; "<fontname>" is the name of a
7103: valid PostScript font; <fontsize> is the size of the font in PostScript
7104: points, before scaling by the @ref{size} command. Selecting `default` sets
7105: all options to their default values: `monochrome`, "Helvetica", and 14pt.
7106:
7107: Since AI does not really support multiple pages, multiple graphs will be
7108: drawn directly on top of one another. However, each graph will be grouped
7109: individually, making it easy to separate them inside AI (just pick them up
7110: and move them).
7111:
7112: Examples:
7113: @example
7114: set term aifm
7115: set term aifm 22
7116: set size 0.7,1.4; set term aifm color "Times-Roman" 14"
7117:
7118: @end example
7119:
7120: @node cgm, corel, aifm, terminal
7121: @subsubsection cgm
7122:
7123: @c ?commands set terminal cgm
7124: @c ?set terminal cgm
7125: @c ?set term cgm
7126: @c ?terminal cgm
7127: @c ?term cgm
7128: @cindex cgm
7129: @tmindex cgm
7130:
7131:
7132: The `cgm` terminal generates a Computer Graphics Metafile. This file format
7133: is a subset of the ANSI X3.122-1986 standard entitled "Computer Graphics -
7134: Metafile for the Storage and Transfer of Picture Description Information".
7135: Several options may be set in `cgm`.
7136:
7137: Syntax:
7138: @example
7139: set terminal cgm @{<mode>@} @{<color>@} @{<rotation>@} @{solid | dashed@}
7140: @{width <plot_width>@} @{linewidth <line_width>@}
7141: @{"<font>"@} @{<fontsize>@}
7142:
7143: @end example
7144:
7145: where <mode> is `landscape`, `portrait`, or `default`;
7146: <color> is either `color` or `monochrome`;
7147: <rotation> is either `rotate` or `norotate`;
7148: `solid` draws all curves with solid lines, overriding any dashed patterns;
7149: <plot_width> is the width of the page in points;
7150: <line_width> is the line width in points;
7151: <font> is the name of a font; and
7152: `<fontsize>` is the size of the font in points.
7153:
7154: By default, `cgm` uses rotated text for the Y axis label.
7155:
7156: The first six options can be in any order. Selecting `default` sets all
7157: options to their default values.
7158:
7159: Examples:
7160: @example
7161: set terminal cgm landscape color rotate dashed width 432 \\
7162: linewidth 1 'Arial Bold' 12 # defaults
7163: set terminal cgm 14 linewidth 2 14 # wider lines & larger font
7164: set terminal cgm portrait 'Times Roman Italic' 12
7165: set terminal cgm color solid # no pesky dashes!
7166:
7167: @end example
7168:
7169:
7170: @noindent --- FONT ---
7171:
7172: @c ?commands set terminal cgm font
7173: @c ?set terminal cgm font
7174: @c ?set term cgm font
7175: @c ?cgm font
7176: The first part of a Computer Graphics Metafile, the metafile description,
7177: includes a font table. In the picture body, a font is designated by an
7178: index into this table. By default, this terminal generates a table with
7179: the following fonts:
7180:
7181: @example
7182: Arial
7183: Arial Italic
7184: Arial Bold
7185: Arial Bold Italic
7186: Times Roman
7187: Times Roman Italic
7188: Times Roman Bold
7189: Times Roman Bold Italic
7190: Helvetica
7191: Roman
7192:
7193: @end example
7194:
7195: Case is not distinct, but the modifiers must appear in the above order (that
7196: is, not 'Arial Italic Bold'). 'Arial Bold' is the default font.
7197:
7198: You may also specify a font name which does not appear in the default font
7199: table. In that case, a new font table is constructed with the specified
7200: font as its only entry. You must ensure that the spelling, capitalization,
7201: and spacing of the name are appropriate for the application that will read
7202: the CGM file.
7203:
7204:
7205: @noindent --- FONTSIZE ---
7206:
7207: @c ?commands set terminal cgm fontsize
7208: @c ?set terminal cgm fontsize
7209: @c ?set term cgm fontsize
7210: @c ?cgm fontsize
7211: Fonts are scaled assuming the page is 6 inches wide. If the @ref{size} command
7212: is used to change the aspect ratio of the page or the CGM file is converted
7213: to a different width (e.g. it is imported into a document in which the
7214: margins are not 6 inches apart), the resulting font sizes will be different.
7215: To change the assumed width, use the `width` option.
7216:
7217:
7218: @noindent --- LINEWIDTH ---
7219:
7220: @c ?commands set terminal cgm linewidth
7221: @c ?set terminal cgm linewidth
7222: @c ?set term cgm linewidth
7223: @c ?cgm linewidth
7224: The `linewidth` option sets the width of lines in pt. The default width is
7225: 1 pt. Scaling is affected by the actual width of the page, as discussed
7226: under the `fontsize` and `width` options
7227:
7228:
7229: @noindent --- ROTATE ---
7230:
7231: @c ?commands set terminal cgm rotate
7232: @c ?set terminal cgm rotate
7233: @c ?set term cgm rotate
7234: @c ?cgm rotate
7235: The `norotate` option may be used to disable text rotation. For example,
7236: the CGM input filter for Word for Windows 6.0c can accept rotated text, but
7237: the DRAW editor within Word cannot. If you edit a graph (for example, to
7238: label a curve), all rotated text is restored to horizontal. The Y axis
7239: label will then extend beyond the clip boundary. With `norotate`, the Y
7240: axis label starts in a less attractive location, but the page can be edited
7241: without damage. The `rotate` option confirms the default behavior.
7242:
7243:
7244: @noindent --- SOLID ---
7245:
7246: @c ?set terminal cgm solid
7247: @c ?set term cgm solid
7248: @c ?cgm solid
7249: The `solid` option may be used to disable dashed line styles in the
7250: plots. This is useful when color is enabled and the dashing of the lines
7251: detracts from the appearance of the plot. The `dashed` option confirms the
7252: default behavior, which gives a different dash pattern to each curve.
7253:
7254:
7255: @noindent --- SIZE ---
7256:
7257: @c ?commands set terminal cgm size
7258: @c ?set terminal cgm size
7259: @c ?set term cgm size
7260: @c ?scgm size
7261: Default size of a CGM page is 32599 units wide and 23457 units high for
7262: landscape, or 23457 units wide by 32599 units high for portrait.
7263:
7264:
7265: @noindent --- WIDTH ---
7266:
7267: @c ?commands set terminal cgm width
7268: @c ?set terminal cgm width
7269: @c ?set term cgm width
7270: @c ?cgm width
7271: All distances in the CGM file are in abstract units. The application that
7272: reads the file determines the size of the final page. By default, the width
7273: of the final page is assumed to be 6 inches (15.24 cm). This distance is
7274: used to calculate the correct font size, and may be changed with the `width`
7275: option. The keyword should be followed by the width in points. (Here, a
7276: point is 1/72 inch, as in PostScript. This unit is known as a "big point"
7277: in TeX.) `gnuplot` arithmetic can be used to convert from other units, as
7278: follows:
7279: @example
7280: set terminal cgm width 432 # default
7281: set terminal cgm width 6*72 # same as above
7282: set terminal cgm width 10/2.54*72 # 10 cm wide
7283:
7284: @end example
7285:
7286:
7287: @noindent --- WINWORD6 ---
7288:
7289: @c ?commands set terminal cgm winword6
7290: @c ?set terminal cgm winword6
7291: @c ?set term cgm winword6
7292: @c ?cgm winword6
7293: The default font table was chosen to match, where possible, the default font
7294: assignments made by the Computer Graphics Metafile input filter for
7295: Microsoft Word 6.0c, although the filter makes available only 'Arial' and
7296: 'Times Roman' fonts and their bold and/or italic variants. Other fonts such
7297: as 'Helvetica' and 'Roman' are not available. If the CGM file includes a
7298: font table, the filter mostly ignores it. However, it changes certain font
7299: assignments so that they disagree with the table. As a workaround, the
7300: `winword6` option deletes the font table from the CGM file. In this case,
7301: the filter makes predictable font assignments. 'Arial Bold' is correctly
7302: assigned even with the font table present, which is one reason it was chosen
7303: as the default.
7304:
7305: `winword6` disables the color tables for a similar reason---with the color
7306: table included, Microsoft Word displays black for color 7.
7307:
7308: Linewidths and pointsizes may be changed with @ref{linestyle}."
7309:
7310: @node corel, dumb, cgm, terminal
7311: @subsubsection corel
7312:
7313: @c ?commands set terminal corel
7314: @c ?set terminal corel
7315: @c ?set term corel
7316: @c ?terminal corel
7317: @c ?term corel
7318: @cindex corel
7319: @tmindex corel
7320:
7321:
7322: The `corel` terminal driver supports CorelDraw.
7323:
7324: Syntax:
7325: @example
7326: set terminal corel @{ default
7327: | @{monochrome | color
7328: @{<fontname> @{"<fontsize>"
7329: @{<xsize> <ysize> @{<linewidth> @}@}@}@}@}
7330:
7331: @end example
7332:
7333: where the fontsize and linewidth are specified in points and the sizes in
7334: inches. The defaults are monochrome, "SwitzerlandLight", 22, 8.2, 10 and 1.2."
7335:
7336: @node dumb, dxf, corel, terminal
7337: @subsubsection dumb
7338:
7339: @c ?commands set terminal dumb
7340: @c ?set terminal dumb
7341: @c ?set term dumb
7342: @c ?terminal dumb
7343: @c ?term dumb
7344: @cindex dumb
7345: @tmindex dumb
7346:
7347:
7348: The `dumb` terminal driver has an optional size specification and trailing
7349: linefeed control.
7350:
7351: Syntax:
7352: @example
7353: set terminal dumb @{[no]feed@} @{<xsize> <ysize>@}
7354:
7355: @end example
7356:
7357: where <xsize> and <ysize> set the size of the dumb terminals. Default is
7358: 79 by 24. The last newline is printed only if `feed` is enabled.
7359:
7360: Examples:
7361: @example
7362: set term dumb nofeed
7363: set term dumb 79 49 # VGA screen---why would anyone do that?"
7364:
7365: @end example
7366:
7367: @node dxf, eepic, dumb, terminal
7368: @subsubsection dxf
7369:
7370: @c ?commands set terminal dxf
7371: @c ?set terminal dxf
7372: @c ?set term dxf
7373: @c ?terminal dxf
7374: @c ?term dxf
7375: @cindex dxf
7376: @tmindex dxf
7377:
7378:
7379: The `dxf` terminal driver creates pictures that can be imported into AutoCad
7380: (Release 10.x). It has no options of its own, but some features of its plots
7381: may be modified by other means. The default size is 120x80 AutoCad units,
7382: which can be changed by @ref{size}. `dxf` uses seven colors (white, red,
7383: yellow, green, cyan, blue and magenta), which can be changed only by
7384: modifying the source file. If a black-and-white plotting device is used, the
7385: colors are mapped to differing line thicknesses. See the description of the
7386: AutoCad print/plot command."
7387:
7388: @node eepic, epson-180dpi, dxf, terminal
7389: @subsubsection eepic
7390:
7391: @c ?commands set terminal eepic
7392: @c ?set terminal eepic
7393: @c ?set term eepic
7394: @c ?terminal eepic
7395: @c ?term eepic
7396: @cindex eepic
7397: @tmindex eepic
7398:
7399:
7400: The `eepic` terminal driver supports the extended LaTeX picture environment.
7401: It is an alternative to the `latex` driver.
7402:
7403: The output of this terminal is intended for use with the "eepic.sty" macro
7404: package for LaTeX. To use it, you need "eepic.sty", "epic.sty" and a
7405: printer driver that supports the "tpic" \\specials. If your printer driver
7406: doesn't support those \\specials, "eepicemu.sty" will enable you to use some
7407: of them.
7408:
7409: Although dotted and dashed lines are possible with `eepic` and are tempting,
7410: they do not work well for high-sample-rate curves, fusing the dashes all
7411: together into a solid line. For now, the `eepic` driver creates only solid
7412: lines. There is another gnuplot driver (`tpic`) that supports dashed lines,
7413: but it cannot be used if your DVI driver doesn't support "tpic" \\specials.
7414:
7415: All drivers for LaTeX offer a special way of controlling text positioning:
7416: If any text string begins with '@{', you also need to include a '@}' at the
7417: end of the text, and the whole text will be centered both horizontally
7418: and vertically by LaTeX. --- If the text string begins with '[', you need
7419: to continue it with: a position specification (up to two out of t,b,l,r),
7420: ']@{', the text itself, and finally, '@}'. The text itself may be anything
7421: LaTeX can typeset as an LR-box. \\rule@{@}@{@}'s may help for best positioning.
7422:
7423: The `eepic` terminal has no options.
7424:
7425: Examples:
7426: About label positioning:
7427: Use gnuplot defaults (mostly sensible, but sometimes not really best):
7428: @example
7429: set title '\\LaTeX\\ -- $ \\gamma $'
7430: @end example
7431:
7432: Force centering both horizontally and vertically:
7433: @example
7434: set label '@{\\LaTeX\\ -- $ \\gamma $@}' at 0,0
7435: @end example
7436:
7437: Specify own positioning (top here):
7438: @example
7439: set xlabel '[t]@{\\LaTeX\\ -- $ \\gamma $@}'
7440: @end example
7441:
7442: The other label -- account for long ticlabels:
7443: @example
7444: set ylabel '[r]@{\\LaTeX\\ -- $ \\gamma $\\rule@{7mm@}@{0pt@}'"
7445:
7446: @end example
7447:
7448: @node epson-180dpi, fig, eepic, terminal
7449: @subsubsection epson-180dpi
7450:
7451: @c ?commands set terminal epson-180dpi
7452: @c ?set terminal epson-180dpi
7453: @c ?set term epson-180dpi
7454: @c ?terminal epson-180dpi
7455: @c ?term epson-180dpi
7456: @cindex epson-180dpi
7457: @tmindex epson-180dpi
7458:
7459:
7460: @c ?commands set terminal epson-60dpi
7461: @c ?set terminal epson-60dpi
7462: @c ?set term epson-60dpi
7463: @c ?terminal epson-60dpi
7464: @c ?term epson-60dpi
7465: @cindex epson-60dpi
7466: @tmindex epson-60dpi
7467:
7468:
7469: @c ?commands set terminal epson-lx800
7470: @c ?set terminal epson-lx800
7471: @c ?set term epson-lx800
7472: @c ?terminal epson-lx800
7473: @c ?term epson-lx800
7474: @cindex epson-lx800
7475: @tmindex epson-lx800
7476:
7477:
7478: @c ?commands set terminal nec-cp6
7479: @c ?set terminal nec-cp6
7480: @c ?set term nec-cp6
7481: @c ?terminal nec-cp6
7482: @c ?term nec-cp6
7483: @cindex nec-cp6
7484: @tmindex nec-cp6
7485:
7486:
7487: @c ?commands set terminal okidata
7488: @c ?set terminal okidata
7489: @c ?set term okidata
7490: @c ?terminal okidata
7491: @c ?term okidata
7492: @cindex okidata
7493: @tmindex okidata
7494:
7495:
7496: @c ?commands set terminal starc
7497: @c ?set terminal starc
7498: @c ?set term starc
7499: @c ?terminal starc
7500: @c ?term starc
7501: @cindex starc
7502: @tmindex starc
7503:
7504:
7505: @c ?commands set terminal tandy-60dpi
7506: @c ?set terminal tandy-60dpi
7507: @c ?set term tandy-60dpi
7508: @c ?terminal tandy-60dpi
7509: @c ?term tandy-60dpi
7510: @cindex tandy-60dpi
7511: @tmindex tandy-60dpi
7512:
7513:
7514: This driver supports a family of Epson printers and derivatives.
7515:
7516: `epson-180dpi` and `epson-60dpi` are drivers for Epson LQ-style 24-pin
7517: printers with resolutions of 180 and 60 dots per inch, respectively.
7518:
7519: `epson-lx800` is a generic 9-pin driver appropriate for printers like the
7520: Epson LX-800, the Star NL-10 and NX-1000, the PROPRINTER, and so forth.
7521:
7522: `nec-cp6` is generix 24-pin driver that can be used for printers like the
7523: NEC CP6 and the Epson LQ-800.
7524:
7525: The `okidata` driver supports the 9-pin OKIDATA 320/321 Standard printers.
7526:
7527: The `starc` driver is for the Star Color Printer.
7528:
7529: The `tandy-60dpi` driver is for the Tandy DMP-130 series of 9-pin, 60-dpi
7530: printers.
7531:
7532: Only `nec-cp6` has any options.
7533:
7534: Syntax:
7535: @example
7536: set terminal nec-cp6 @{monochrome | colour | draft@}
7537:
7538: @end example
7539:
7540: which defaults to monochrome.
7541:
7542: With each of these drivers, a binary copy is required on a PC to print. Do
7543: not use @ref{print}---use instead `copy file /b lpt1:`."
7544:
7545: @node fig, gif, epson-180dpi, terminal
7546: @subsubsection fig
7547:
7548: @c ?commands set terminal fig
7549: @c ?set terminal fig
7550: @c ?set term fig
7551: @c ?terminal fig
7552: @c ?term fig
7553: @cindex fig
7554: @tmindex fig
7555:
7556:
7557: The `fig` terminal device generates output in the Fig graphics language.
7558:
7559: Syntax:
7560: @example
7561: set terminal fig @{monochrome | color@} @{small | big@}
7562: @{pointsmax <max_points>@}
7563: @{landscape | portrait@}
7564: @{metric | inches@}
7565: @{fontsize <fsize>@}
7566: @{size <xsize> <ysize>@}
7567: @{thickness <units>@}
7568: @{depth <layer>@}
7569:
7570: @end example
7571:
7572: `monochrome` and `color` determine whether the picture is black-and-white or
7573: `color`. `small` and `big` produce a 5x3 or 8x5 inch graph in the default
7574: `landscape` mode and 3x5 or 5x8 inches in `portrait` mode. <max_points>
7575: sets the maximum number of points per polyline. Default units for editing
7576: with "xfig" may be `metric` or `inches`. `fontsize` sets the size of the
7577: text font to <fsize> points. @ref{size} sets (overrides) the size of the drawing
7578: area to <xsize>*<ysize> in units of inches or centimeters depending on the
7579: `inches` or `metric` setting in effect. `depth` sets the default depth layer
7580: for all lines and text. The default depth is 10 to leave room for adding
7581: material with "xfig" on top of the plot.
7582:
7583: `thickness` sets the default line thickness, which is 1 if not specified.
7584: Overriding the thickness can be achieved by adding a multiple of 100 to the
7585: to the `linetype` value for a @ref{plot} command. In a similar way the `depth`
7586: of plot elements (with respect to the default depth) can be controlled by
7587: adding a multiple of 1000 to <linetype>. The depth is then <layer> +
7588: <linetype>/1000 and the thickness is (<linetype>%1000)/100 or, if that is
7589: zero, the default line thickness.
7590:
7591: Additional point-plot symbols are also available with the `fig` driver. The
7592: symbols can be used through `pointtype` values % 100 above 50, with different
7593: fill intensities controlled by <pointtype> % 5 and outlines in black (for
7594: <pointtype> % 10 < 5) or in the current color. Available symbols are
7595: @example
7596: 50 - 59: circles
7597: 60 - 69: squares
7598: 70 - 79: diamonds
7599: 80 - 89: upwards triangles
7600: 90 - 99: downwards triangles
7601: @end example
7602:
7603: The size of these symbols is linked to the font size. The depth of symbols
7604: is by default one less than the depth for lines to achieve nice error bars.
7605: If <pointtype> is above 1000, the depth is <layer> + <pointtype>/1000-1. If
7606: <pointtype>%1000 is above 100, the fill color is (<pointtype>%1000)/100-1.
7607:
7608: Available fill colors are (from 1 to 9): black, blue, green, cyan, red,
7609: magenta, yellow, white and dark blue (in monochrome mode: black for 1 to 6
7610: and white for 7 to 9).
7611:
7612: See @ref{with} for details of <linetype> and <pointtype>.
7613:
7614: The `big` option is a substitute for the `bfig` terminal in earlier versions,
7615: which is no longer supported.
7616:
7617: Examples:
7618: @example
7619: set terminal fig monochrome small pointsmax 1000 # defaults
7620:
7621: @end example
7622:
7623: @example
7624: plot 'file.dat' with points linetype 102 pointtype 759
7625: @end example
7626:
7627: would produce circles with a blue outline of width 1 and yellow fill color.
7628:
7629: @example
7630: plot 'file.dat' using 1:2:3 with err linetype 1 pointtype 554
7631: @end example
7632:
7633: would produce errorbars with black lines and circles filled red. These
7634: circles are one layer above the lines (at depth 9 by default).
7635:
7636: To plot the error bars on top of the circles use
7637: @example
7638: plot 'file.dat' using 1:2:3 with err linetype 1 pointtype 2554"
7639:
7640: @end example
7641:
7642: @node gif, gpic, fig, terminal
7643: @subsubsection gif
7644:
7645: @c ?commands set terminal gif
7646: @c ?set terminal gif
7647: @c ?set term gif
7648: @c ?terminal gif
7649: @c ?term gif
7650: @cindex gif
7651: @tmindex gif
7652:
7653:
7654: The `gif` terminal driver generates output in GIF format. It uses Thomas
7655: Boutell's gd library, which is available from http://www.boutell.com/gd/
7656:
7657: By default, the `gif` terminal driver uses a shared Web-friendy palette."
7658:
7659: Syntax:
7660: @example
7661: set terminal gif @{transparent@} @{interlace@}
7662: @{tiny | small | medium | large | giant@}
7663: @{size <x>,<y>@}
7664: @{<color0> <color1> <color2> ...@}
7665:
7666: @end example
7667:
7668: `transparent` instructs the driver to generate transparent GIFs. The first
7669: color will be the transparent one.
7670:
7671: `interlace` instructs the driver to generate interlaced GIFs.
7672:
7673: The choice of fonts is `tiny` (5x8 pixels), `small` (6x12 pixels), `medium`
7674: (7x13 Bold), `large` (8x16) or `giant` (9x15 pixels)
7675:
7676: The size <x,y> is given in pixels---it defaults to 640x480. The number of
7677: pixels can be also modified by scaling with the @ref{size} command.
7678:
7679: Each color must be of the form 'xrrggbb', where x is the literal character
7680: 'x' and 'rrggbb' are the red, green and blue components in hex. For example,
7681: 'x00ff00' is green. The background color is set first, then the border
7682: colors, then the X & Y axis colors, then the plotting colors. The maximum
7683: number of colors that can be set is 256.
7684:
7685: Examples:
7686: @example
7687: set terminal gif small size 640,480 \\
7688: xffffff x000000 x404040 \\
7689: xff0000 xffa500 x66cdaa xcdb5cd \\
7690: xadd8e6 x0000ff xdda0dd x9500d3 # defaults
7691:
7692: @end example
7693:
7694: which uses white for the non-transparent background, black for borders, gray
7695: for the axes, and red, orange, medium aquamarine, thistle 3, light blue, blue,
7696: plum and dark violet for eight plotting colors.
7697:
7698: @example
7699: set terminal gif transparent xffffff \\
7700: x000000 x202020 x404040 x606060 \\
7701: x808080 xA0A0A0 xC0C0C0 xE0E0E0 \\
7702: @end example
7703:
7704: which uses white for the transparent background, black for borders, dark
7705: gray for axes, and a gray-scale for the six plotting colors.
7706:
7707: The page size is 640x480 pixels. The `gif` driver can create either color
7708: or monochromatic output, but you have no control over which is produced.
7709:
7710: The current version of the `gif` driver does not support animated GIFs."
7711:
7712: @node gpic, hp2623a, gif, terminal
7713: @subsubsection gpic
7714:
7715: @c ?commands set terminal gpic
7716: @c ?set terminal gpic
7717: @c ?set term gpic
7718: @c ?terminal gpic
7719: @c ?term gpic
7720: @cindex gpic
7721: @tmindex gpic
7722:
7723:
7724: The `gpic` terminal driver generates GPIC graphs in the Free Software
7725: Foundations's "groff" package. The default size is 5 x 3 inches. The only
7726: option is the origin, which defaults to (0,0).
7727:
7728: Syntax:
7729: @example
7730: set terminal gpic @{<x> <y>@}
7731:
7732: @end example
7733:
7734: where `x` and `y` are in inches.
7735:
7736: A simple graph can be formatted using
7737:
7738: @example
7739: groff -p -mpic -Tps file.pic > file.ps.
7740:
7741: @end example
7742:
7743: The output from pic can be pipe-lined into eqn, so it is possible to put
7744: complex functions in a graph with the @ref{label} and `set @{x/y@}label`
7745: commands. For instance,
7746:
7747: @example
7748: set ylab '@@space 0 int from 0 to x alpha ( t ) roman d t@@'
7749:
7750: @end example
7751:
7752: will label the y axis with a nice integral if formatted with the command:
7753:
7754: @example
7755: gpic filename.pic | geqn -d@@@@ -Tps | groff -m[macro-package] -Tps
7756: > filename.ps
7757:
7758: @end example
7759:
7760: Figures made this way can be scaled to fit into a document. The pic language
7761: is easy to understand, so the graphs can be edited by hand if need be. All
7762: co-ordinates in the pic-file produced by `gnuplot` are given as x+gnuplotx
7763: and y+gnuploty. By default x and y are given the value 0. If this line is
7764: removed with an editor in a number of files, one can put several graphs in
7765: one figure like this (default size is 5.0x3.0 inches):
7766:
7767: @example
7768: .PS 8.0
7769: x=0;y=3
7770: copy "figa.pic"
7771: x=5;y=3
7772: copy "figb.pic"
7773: x=0;y=0
7774: copy "figc.pic"
7775: x=5;y=0
7776: copy "figd.pic"
7777: .PE
7778:
7779: @end example
7780:
7781: This will produce an 8-inch-wide figure with four graphs in two rows on top
7782: of each other.
7783:
7784: One can also achieve the same thing by the command
7785:
7786: @example
7787: set terminal gpic x y
7788:
7789: @end example
7790:
7791: for example, using
7792:
7793: @example
7794: .PS 6.0
7795: copy "trig.pic"
7796: .PE"
7797:
7798: @end example
7799:
7800: @node hp2623a, hp2648, gpic, terminal
7801: @subsubsection hp2623a
7802:
7803: @c ?commands set terminal hp2623a
7804: @c ?set terminal hp2623a
7805: @c ?set term hp2623a
7806: @c ?terminal hp2623a
7807: @c ?term hp2623a
7808: @cindex hp2623a
7809: @tmindex hp2623a
7810:
7811:
7812: The `hp2623a` terminal driver supports the Hewlett Packard HP2623A. It has
7813: no options."
7814:
7815: @node hp2648, hp500c, hp2623a, terminal
7816: @subsubsection hp2648
7817:
7818: @c ?commands set terminal hp2648
7819: @c ?set terminal hp2648
7820: @c ?set term hp2648
7821: @c ?terminal hp2648
7822: @c ?term hp2648
7823: @cindex hp2648
7824: @tmindex hp2648
7825:
7826:
7827: The `hp2648` terminal driver supports the Hewlett Packard HP2647 and HP2648.
7828: It has no options."
7829:
7830: @node hp500c, hpgl, hp2648, terminal
7831: @subsubsection hp500c
7832:
7833: @c ?commands set terminal hp500c
7834: @c ?set terminal hp500c
7835: @c ?set term hp500c
7836: @c ?terminal hp500c
7837: @c ?term hp500c
7838: @cindex hp500c
7839: @tmindex hp500c
7840:
7841:
7842: The `hp500c` terminal driver supports the Hewlett Packard HP DeskJet 500c.
7843: It has options for resolution and compression.
7844:
7845: Syntax:
7846: @example
7847: set terminal hp500c @{<res>@} @{<comp>@}
7848:
7849: @end example
7850:
7851: where `res` can be 75, 100, 150 or 300 dots per inch and `comp` can be "rle",
7852: or "tiff". Any other inputs are replaced by the defaults, which are 75 dpi
7853: and no compression. Rasterization at the higher resolutions may require a
7854: large amount of memory."
7855:
7856: @node hpgl, hpljii, hp500c, terminal
7857: @subsubsection hpgl
7858:
7859: @c ?commands set terminal hpgl
7860: @c ?set terminal hpgl
7861: @c ?set term hpgl
7862: @c ?terminal hpgl
7863: @c ?term hpgl
7864: @cindex hpgl
7865: @tmindex hpgl
7866:
7867:
7868: @c ?commands set terminal pcl5
7869: @c ?set terminal pcl5
7870: @c ?set term pcl5
7871: @c ?terminal pcl5
7872: @c ?term pcl5
7873: @cindex pcl5
7874: @tmindex pcl5
7875:
7876:
7877: The `hpgl` driver produces HPGL output for devices like the HP7475A plotter.
7878: There are two options which can be set---the number of pens and "eject", which
7879: tells the plotter to eject a page when done. The default is to use 6 pens
7880: and not to eject the page when done.
7881:
7882: The international character sets ISO-8859-1 and CP850 are recognized via
7883: `set encoding iso_8859_1` or `set encoding cp850` (see @ref{encoding} for
7884: details).
7885:
7886: Syntax:
7887: @example
7888: set terminal hpgl @{<number_of_pens>@} @{eject@}
7889:
7890: @end example
7891:
7892: The selection
7893:
7894: @example
7895: set terminal hpgl 8 eject
7896:
7897: @end example
7898:
7899: is equivalent to the previous `hp7550` terminal, and the selection
7900:
7901: @example
7902: set terminal hpgl 4
7903:
7904: @end example
7905:
7906: is equivalent to the previous `hp7580b` terminal.
7907:
7908: The `pcl5` driver supports the Hewlett-Packard Laserjet III. It actually uses
7909: HPGL-2, but there is a name conflict among the terminal devices. It has
7910: several options
7911:
7912: Syntax:
7913: @example
7914: set terminal pcl5 @{<mode>@} @{<font>@} @{<fontsize>@}
7915:
7916: @end example
7917:
7918: where <mode> is `landscape`, or `portrait`, <font> is `stick`, `univers`, or
7919: `cg_times`, and <fontsize> is the size in points.
7920:
7921: With `pcl5` international characters are handled by the printer; you just put
7922: the appropriate 8-bit character codes into the text strings. You don't need
7923: to bother with @ref{encoding}.
7924:
7925: HPGL graphics can be imported by many software packages."
7926:
7927: @node hpljii, hppj, hpgl, terminal
7928: @subsubsection hpljii
7929:
7930: @c ?commands set terminal hpljii
7931: @c ?set terminal hpljii
7932: @c ?set term hpljii
7933: @c ?terminal hpljii
7934: @c ?term hpljii
7935: @cindex hpljii
7936: @tmindex hpljii
7937:
7938:
7939: @c ?commands set terminal hpdj
7940: @c ?set terminal hpdj
7941: @c ?set term hpdj
7942: @c ?terminal hpdj
7943: @c ?term hpdj
7944: @cindex hpdj
7945: @tmindex hpdj
7946:
7947:
7948: The `hpljii` terminal driver supports the HP Laserjet Series II printer. The
7949: `hpdj` driver supports the HP DeskJet 500 printer. These drivers allow a
7950: choice of resolutions.
7951:
7952: Syntax:
7953: @example
7954: set terminal hpljii | hpdj @{<res>@}
7955:
7956: @end example
7957:
7958: where `res` may be 75, 100, 150 or 300 dots per inch; the default is 75.
7959: Rasterization at the higher resolutions may require a large amount of memory.
7960:
7961: The `hp500c` terminal is similar to `hpdj`; `hp500c` additionally supports
7962: color and compression."
7963:
7964: @node hppj, imagen, hpljii, terminal
7965: @subsubsection hppj
7966:
7967: @c ?commands set terminal hppj
7968: @c ?set terminal hppj
7969: @c ?set term hppj
7970: @c ?terminal hppj
7971: @c ?term hppj
7972: @cindex hppj
7973: @tmindex hppj
7974:
7975:
7976: The `hppj` terminal driver supports the HP PaintJet and HP3630 printers. The
7977: only option is the choice of font.
7978:
7979: Syntax:
7980: @example
7981: set terminal hppj @{FNT5X9 | FNT9X17 | FNT13X25@}
7982:
7983: @end example
7984:
7985: with the middle-sized font (FNT9X17) being the default."
7986:
7987: @node imagen, latex, hppj, terminal
7988: @subsubsection imagen
7989:
7990: @c ?commands set terminal imagen
7991: @c ?set terminal imagen
7992: @c ?set term imagen
7993: @c ?terminal imagen
7994: @c ?term imagen
7995: @cindex imagen
7996: @tmindex imagen
7997:
7998:
7999: The `imagen` terminal driver supports Imagen laser printers. It is capable
8000: of placing multiple graphs on a single page.
8001:
8002: Syntax:
8003: @example
8004: set terminal imagen @{<fontsize>@} @{portrait | landscape@}
8005: @{[<horiz>,<vert>]@}
8006:
8007: @end example
8008:
8009: where `fontsize` defaults to 12 points and the layout defaults to `landscape`.
8010: `<horiz>` and `<vert>` are the number of graphs in the horizontal and
8011: vertical directions; these default to unity.
8012:
8013: Example:
8014: @example
8015: set terminal imagen portrait [2,3]
8016:
8017: @end example
8018:
8019: puts six graphs on the page in three rows of two in portrait orientation."
8020:
8021: @node latex, mf, imagen, terminal
8022: @subsubsection latex
8023:
8024: @c ?commands set terminal emtex
8025: @c ?set terminal emtex
8026: @c ?set term emtex
8027: @c ?terminal emtex
8028: @c ?term emtex
8029: @cindex latex
8030: @tmindex latex
8031:
8032:
8033: @c ?commands set terminal latex
8034: @c ?set terminal latex
8035: @c ?set term latex
8036: @c ?terminal latex
8037: @c ?term latex
8038: @cindex emtex
8039: @tmindex emtex
8040:
8041:
8042: The `latex` and `emtex` drivers allow two options.
8043:
8044: Syntax:
8045: @example
8046: set terminal latex | emtex @{courier | roman | default@} @{<fontsize>@}
8047:
8048: @end example
8049:
8050: `fontsize` may be any size you specify. The default is for the plot to
8051: inherit its font setting from the embedding document.
8052:
8053: Unless your driver is capable of building fonts at any size (e.g. dvips),
8054: stick to the standard 10, 11 and 12 point sizes.
8055:
8056: METAFONT users beware: METAFONT does not like odd sizes.
8057:
8058: All drivers for LaTeX offer a special way of controlling text positioning:
8059: If any text string begins with '@{', you also need to include a '@}' at the
8060: end of the text, and the whole text will be centered both horizontally and
8061: vertically. If the text string begins with '[', you need to follow this with
8062: a position specification (up to two out of t,b,l,r), ']@{', the text itself,
8063: and finally '@}'. The text itself may be anything LaTeX can typeset as an
8064: LR-box. '\\rule@{@}@{@}'s may help for best positioning.
8065:
8066: Points, among other things, are drawn using the LaTeX commands "\\Diamond" and
8067: "\\Box". These commands no longer belong to the LaTeX2e core; they are included
8068: in the latexsym package, which is part of the base distribution and thus part
8069: of any LaTeX implementation. Please do not forget to use this package.
8070:
8071: Points are drawn with the LaTex commands \\Diamond and \\Box. These
8072: commands do no longer belong to the LaTeX2e core, but are included in the
8073: latexsym-package in the base distribution, and are hence part of all LaTeX
8074: implementations. Please do not forget to use this package.
8075:
8076: Examples:
8077: About label positioning:
8078: Use gnuplot defaults (mostly sensible, but sometimes not really best):
8079: @example
8080: set title '\\LaTeX\\ -- $ \\gamma $'
8081: @end example
8082:
8083: Force centering both horizontally and vertically:
8084: @example
8085: set label '@{\\LaTeX\\ -- $ \\gamma $@}' at 0,0
8086: @end example
8087:
8088: Specify own positioning (top here):
8089: @example
8090: set xlabel '[t]@{\\LaTeX\\ -- $ \\gamma $@}'
8091: @end example
8092:
8093: The other label -- account for long ticlabels:
8094: @example
8095: set ylabel '[r]@{\\LaTeX\\ -- $ \\gamma $\\rule@{7mm@}@{0pt@}'"
8096:
8097: @end example
8098:
8099: @node mf, mif, latex, terminal
8100: @subsubsection mf
8101:
8102: @c ?commands set terminal mf
8103: @c ?set terminal mf
8104: @c ?set term mf
8105: @c ?terminal mf
8106: @c ?term mf
8107: @cindex mf
8108:
8109: @cindex metafont
8110:
8111: The `mf` terminal driver creates a input file to the METAFONT program. Thus a
8112: figure may be used in the TeX document in the same way as is a character.
8113:
8114: To use a picture in a document, the METAFONT program must be run with the
8115: output file from `gnuplot` as input. Thus, the user needs a basic knowledge
8116: of the font creating process and the procedure for including a new font in a
8117: document. However, if the METAFONT program is set up properly at the local
8118: site, an unexperienced user could perform the operation without much trouble.
8119:
8120: The text support is based on a METAFONT character set. Currently the
8121: Computer Modern Roman font set is input, but the user is in principal free to
8122: chose whatever fonts he or she needs. The METAFONT source files for the
8123: chosen font must be available. Each character is stored in a separate
8124: picture variable in METAFONT. These variables may be manipulated (rotated,
8125: scaled etc.) when characters are needed. The drawback is the interpretation
8126: time in the METAFONT program. On some machines (i.e. PC) the limited amount
8127: of memory available may also cause problems if too many pictures are stored.
8128:
8129: The `mf` terminal has no options.
8130:
8131:
8132: @noindent --- METAFONT INSTRUCTIONS ---
8133:
8134: @c ?commands set terminal mf detailed
8135: @c ?set terminal mf detailed
8136: @c ?set term mf detailed
8137: @c ?mf detailed
8138: @c ?metafont detailed
8139:
8140: - Set your terminal to METAFONT:
8141: @example
8142: set terminal mf
8143: @end example
8144:
8145: - Select an output-file, e.g.:
8146: @example
8147: set output "myfigures.mf"
8148: @end example
8149:
8150: - Create your pictures. Each picture will generate a separate character. Its
8151: default size will be 5*3 inches. You can change the size by saying `set size
8152: 0.5,0.5` or whatever fraction of the default size you want to have.
8153:
8154: - Quit `gnuplot`.
8155:
8156: - Generate a TFM and GF file by running METAFONT on the output of `gnuplot`.
8157: Since the picture is quite large (5*3 in), you will have to use a version of
8158: METAFONT that has a value of at least 150000 for memmax. On Unix systems
8159: these are conventionally installed under the name bigmf. For the following
8160: assume that the command virmf stands for a big version of METAFONT. For
8161: example:
8162:
8163: - Invoke METAFONT:
8164: @example
8165: virmf '&plain'
8166: @end example
8167:
8168: - Select the output device: At the METAFONT prompt ('*') type:
8169: @example
8170: \\mode:=CanonCX; % or whatever printer you use
8171: @end example
8172:
8173: - Optionally select a magnification:
8174: @example
8175: mag:=1; % or whatever you wish
8176: @end example
8177:
8178: - Input the `gnuplot`-file:
8179: @example
8180: input myfigures.mf
8181: @end example
8182:
8183: On a typical Unix machine there will usually be a script called "mf" that
8184: executes virmf '&plain', so you probably can substitute mf for virmf &plain.
8185: This will generate two files: mfput.tfm and mfput.$$$gf (where $$$ indicates
8186: the resolution of your device). The above can be conveniently achieved by
8187: typing everything on the command line, e.g.:
8188: virmf '&plain' '\\mode:=CanonCX; mag:=1; input myfigures.mf'
8189: In this case the output files will be named myfigures.tfm and
8190: myfigures.300gf.
8191:
8192: - Generate a PK file from the GF file using gftopk:
8193: @example
8194: gftopk myfigures.300gf myfigures.300pk
8195: @end example
8196:
8197: The name of the output file for gftopk depends on the DVI driver you use.
8198: Ask your local TeX administrator about the naming conventions. Next, either
8199: install the TFM and PK files in the appropriate directories, or set your
8200: environment variables properly. Usually this involves setting TEXFONTS to
8201: include the current directory and doing the same thing for the environment
8202: variable that your DVI driver uses (no standard name here...). This step is
8203: necessary so that TeX will find the font metric file and your DVI driver will
8204: find the PK file.
8205:
8206: - To include your pictures in your document you have to tell TeX the font:
8207: @example
8208: \\font\\gnufigs=myfigures
8209: @end example
8210:
8211: Each picture you made is stored in a single character. The first picture is
8212: character 0, the second is character 1, and so on... After doing the above
8213: step, you can use the pictures just like any other characters. Therefore, to
8214: place pictures 1 and 2 centered in your document, all you have to do is:
8215: @example
8216: \\centerline@{\\gnufigs\\char0@}
8217: \\centerline@{\\gnufigs\\char1@}
8218: @end example
8219:
8220: in plain TeX. For LaTeX you can, of course, use the picture environment and
8221: place the picture wherever you wish by using the \\makebox and \\put macros.
8222:
8223: This conversion saves you a lot of time once you have generated the font;
8224: TeX handles the pictures as characters and uses minimal time to place them,
8225: and the documents you make change more often than the pictures do. It also
8226: saves a lot of TeX memory. One last advantage of using the METAFONT driver
8227: is that the DVI file really remains device independent, because no \\special
8228: commands are used as in the eepic and tpic drivers."
8229:
8230: @node mif, pbm, mf, terminal
8231: @subsubsection mif
8232:
8233: @c ?commands set terminal mif
8234: @c ?set terminal mif
8235: @c ?set term mif
8236: @c ?terminal mif
8237: @c ?term mif
8238: @cindex mif
8239: @tmindex mif
8240:
8241:
8242: The `mif` terminal driver produces Frame Maker MIF format version 3.00. It
8243: plots in MIF Frames with the size 15*10 cm, and plot primitives with the same
8244: pen will be grouped in the same MIF group. Plot primitives in a `gnuplot`
8245: page will be plotted in a MIF Frame, and several MIF Frames are collected in
8246: one large MIF Frame. The MIF font used for text is "Times".
8247:
8248: Several options may be set in the MIF 3.00 driver.
8249:
8250: Syntax:
8251: @example
8252: set terminal mif @{colour | monochrome@} @{polyline | vectors@}
8253: @{help | ?@}
8254:
8255: @end example
8256:
8257: `colour` plots lines with line types >= 0 in colour (MIF sep. 2--7) and
8258: `monochrome` plots all line types in black (MIF sep. 0).
8259: `polyline` plots curves as continuous curves and `vectors` plots curves as
8260: collections of vectors.
8261: @ref{help} and `?` print online help on standard error output---both print a
8262: short description of the usage; @ref{help} also lists the options;
8263:
8264: Examples:
8265: @example
8266: set term mif colour polylines # defaults
8267: set term mif # defaults
8268: set term mif vectors
8269: set term mif help"
8270:
8271: @end example
8272:
8273: @node pbm, png, mif, terminal
8274: @subsubsection pbm
8275:
8276: @c ?commands set terminal pbm
8277: @c ?set terminal pbm
8278: @c ?set term pbm
8279: @c ?terminal pbm
8280: @c ?term pbm
8281: @cindex pbm
8282: @tmindex pbm
8283:
8284:
8285: Several options may be set in the `pbm` terminal---the driver for PBMplus.
8286:
8287: Syntax:
8288: @example
8289: set terminal pbm @{<fontsize>@} @{<mode>@}
8290:
8291: @end example
8292:
8293: where <fontsize> is `small`, `medium`, or `large` and <mode> is `monochrome`,
8294: `gray` or `color`. The default plot size is 640 pixels wide and 480 pixels
8295: high; this may be changed by @ref{size}.
8296:
8297: The output of the `pbm` driver depends upon <mode>: `monochrome` produces a
8298: portable bitmap (one bit per pixel), `gray` a portable graymap (three bits
8299: per pixel) and `color` a portable pixmap (color, four bits per pixel).
8300:
8301: The output of this driver can be used with Jef Poskanzer's excellent PBMPLUS
8302: package, which provides programs to convert the above PBMPLUS formats to GIF,
8303: TIFF, MacPaint, Macintosh PICT, PCX, X11 bitmap and many others. PBMPLUS may
8304: be obtained from ftp.x.org. The relevant files have names that begin with
8305: "netpbm-1mar1994.p1"; they reside in /contrib/utilities. The package can
8306: probably also be obtained from one of the many sites that mirrors ftp.x.org.
8307:
8308: Examples:
8309: @example
8310: set terminal pbm small monochrome # defaults
8311: set size 2,2; set terminal pbm color medium"
8312:
8313: @end example
8314:
8315: @node png, postscript, pbm, terminal
8316: @subsubsection png
8317:
8318: @c ?commands set terminal png
8319: @c ?set terminal png
8320: @c ?set term png
8321: @c ?terminal png
8322: @c ?term png
8323: @cindex png
8324: @tmindex png
8325:
8326:
8327: The `png` terminal driver supports Portable Network Graphics. To compile it,
8328: you will need the third-party libraries "libpng" and "zlib"; both are
8329: available at ftp://ftp.uu.net/graphics/png. `png` has two options.
8330:
8331: Syntax:
8332: @example
8333: set terminal png @{small | medium | large@}
8334: @{monochrome | gray | color@}
8335:
8336: @end example
8337:
8338: The defaults are small (fontsize) and monochrome. Default size of the output
8339: is 640*480 pixel."
8340:
8341: @node postscript, pslatex_and_pstex, png, terminal
8342: @subsubsection postscript
8343:
8344: @c ?commands set terminal postscript
8345: @c ?set terminal postscript
8346: @c ?set term postscript
8347: @c ?terminal postscript
8348: @c ?term postscript
8349: @cindex postscript
8350: @tmindex postscript
8351:
8352:
8353: Several options may be set in the `postscript` driver.
8354:
8355: Syntax:
8356: @example
8357: set terminal postscript @{<mode>@} @{enhanced | noenhanced@}
8358: @{color | monochrome@} @{solid | dashed@}
8359: @{<duplexing>@}
8360: @{"<fontname>"@} @{<fontsize>@}
8361:
8362: @end example
8363:
8364: where <mode> is `landscape`, `portrait`, `eps` or `default`;
8365: `solid` draws all plots with solid lines, overriding any dashed patterns;
8366: <duplexing> is `defaultplex`, `simplex` or `duplex` ("duplexing" in
8367: PostScript is the ability of the printer to print on both sides of the same
8368: page---don't set this if your printer can't do it);
8369: `enhanced` activates the "enhanced PostScript" features (subscripts,
8370: superscripts and mixed fonts);
8371: `"<fontname>"` is the name of a valid PostScript font; and `<fontsize>` is
8372: the size of the font in PostScript points.
8373:
8374: `default` mode sets all options to their defaults: `landscape`, `monochrome`,
8375: `dashed`, `defaultplex`, `noenhanced`, "Helvetica" and 14pt.
8376: @example
8377: Default size of a PostScript plot is 10 inches wide and 7 inches high.
8378:
8379: @end example
8380:
8381: `eps` mode generates EPS (Encapsulated PostScript) output, which is just
8382: regular PostScript with some additional lines that allow the file to be
8383: imported into a variety of other applications. (The added lines are
8384: PostScript comment lines, so the file may still be printed by itself.) To
8385: get EPS output, use the `eps` mode and make only one plot per file. In `eps`
8386: mode the whole plot, including the fonts, is reduced to half of the default
8387: size.
8388:
8389: Examples:
8390: @example
8391: set terminal postscript default # old postscript
8392: set terminal postscript enhanced # old enhpost
8393: set terminal postscript landscape 22 # old psbig
8394: set terminal postscript eps 14 # old epsf1
8395: set terminal postscript eps 22 # old epsf2
8396: set size 0.7,1.4; set term post portrait color "Times-Roman" 14
8397:
8398: @end example
8399:
8400: Linewidths and pointsizes may be changed with @ref{linestyle}.
8401:
8402: The `postscript` driver supports about 70 distinct pointtypes, selectable
8403: through the `pointtype` option on @ref{plot} and @ref{linestyle}.
8404:
8405: Several possibly useful files about `gnuplot`'s PostScript are included
8406: in the /docs/ps subdirectory of the `gnuplot` distribution and at the
8407: distribution sites. These are "ps_symbols.gpi" (a `gnuplot` command file
8408: that, when executed, creates the file "ps_symbols.ps" which shows all the
8409: symbols available through the `postscript` terminal), "ps_guide.ps" (a
8410: PostScript file that contains a summary of the enhanced syntax and a page
8411: showing what the octal codes produce with text and symbol fonts) and
8412: "ps_file.doc" (a text file that contains a discussion of the organization
8413: of a PostScript file written by `gnuplot`).
8414:
8415: A PostScript file is editable, so once `gnuplot` has created one, you are
8416: free to modify it to your heart's desire. See the "editing postscript"
8417: section for some hints.
8418:
8419:
8420: @noindent --- ENHANCED POSTSCRIPT ---
8421:
8422: @c ?commands set terminal postscript enhanced
8423: @c ?set terminal postscript enhanced
8424: @c ?set term postscript enhanced
8425: @c ?terminal postscript enhanced
8426: @c ?term postscript enhanced
8427: @cindex enhanced_postscript
8428:
8429:
8430: @example
8431: Control Examples Explanation
8432: ^ a^x superscript
8433: _ a_x subscript
8434: @@ @@x or a@@^b_c phantom box (occupies no width)
8435: & &@{space@} inserts space of specified length
8436:
8437: @end example
8438:
8439:
8440: Braces can be used to place multiple-character text where a single character
8441: is expected (e.g., 2^@{10@}). To change the font and/or size, use the full
8442: form: @{/[fontname][=fontsize | *fontscale] text@}. Thus @{/Symbol=20 G@} is a
8443: 20-point GAMMA) and @{/*0.75 K@} is a K at three-quarters of whatever fontsize
8444: is currently in effect. (The '/' character MUST be the first character after
8445: the '@{'.)
8446:
8447: If the encoding vector has been changed by @ref{encoding}, the default
8448: encoding vector can be used instead by following the slash with a dash. This
8449: is unnecessary if you use the Symbol font, however---since /Symbol uses its
8450: own encoding vector, `gnuplot` will not apply any other encoding vector to
8451: it.
8452:
8453: The phantom box is useful for a@@^b_c to align superscripts and subscripts
8454: but does not work well for overwriting an accent on a letter. (To do the
8455: latter, it is much better to use `set encoding iso_8859_1` to change to the
8456: ISO Latin-1 encoding vector, which contains a large variety of letters with
8457: accents or other diacritical marks.) Since the box is non-spacing, it is
8458: sensible to put the shorter of the subscript or superscript in the box (that
8459: is, after the @@).
8460:
8461: Space equal in length to a string can be inserted using the '&' character.
8462: Thus
8463: @example
8464: 'abc&@{def@}ghi'
8465: @end example
8466:
8467: would produce
8468: @example
8469: 'abc ghi'.
8470:
8471: @end example
8472:
8473: You can access special symbols numerically by specifying \\character-code (in
8474: octal), e.g., @{/Symbol \\245@} is the symbol for infinity.
8475:
8476: You can escape control characters using \\, e.g., \\\\, \\@{, and so on.
8477:
8478: But be aware that strings in double-quotes are parsed differently than those
8479: enclosed in single-quotes. The major difference is that backslashes may need
8480: to be doubled when in double-quoted strings.
8481:
8482: Examples (these are hard to describe in words---try them!):
8483: @example
8484: set xlabel 'Time (10^6 @{/Symbol m@}s)'
8485: set title '@{/Symbol=18 \\362@@_@{/=9.6 0@}^@{/=12 x@}@} \\
8486: @{/Helvetica e^@{-@{/Symbol m@}^2/2@} d@}@{/Symbol m@}'
8487:
8488: @end example
8489:
8490: The file "ps_guide.ps" in the /docs/ps subdirectory of the `gnuplot` source
8491: distribution contains more examples of the enhanced syntax.
8492:
8493:
8494: @noindent --- EDITING POSTSCRIPT ---
8495:
8496: @c ?commands set terminal postscript editing
8497: @c ?set terminal postscript editing
8498: @c ?set term postscript editing
8499: @c ?terminal postscript editing
8500: @c ?term postscript editing
8501: @cindex editing_postscript
8502:
8503: The PostScript language is a very complex language---far too complex to
8504: describe in any detail in this document. Nevertheless there are some things
8505: in a PostScript file written by `gnuplot` that can be changed without risk of
8506: introducing fatal errors into the file.
8507:
8508: For example, the PostScript statement "/Color true def" (written into the
8509: file in response to the command `set terminal postscript color`), may be
8510: altered in an obvious way to generate a black-and-white version of a plot.
8511: Similarly line colors, text colors, line weights and symbol sizes can also be
8512: altered in straight-forward ways. Text (titles and labels) can be edited to
8513: correct misspellings or to change fonts. Anything can be repositioned, and
8514: of course anything can be added or deleted, but modifications such as these
8515: may require deeper knowledge of the PostScript language.
8516:
8517: The organization of a PostScript file written by `gnuplot` is discussed in
8518: the text file "ps_file.doc" in the /docs/ps subdirectory."
8519:
8520: @node pslatex_and_pstex, pstricks, postscript, terminal
8521: @subsubsection pslatex and pstex
8522:
8523: @c ?commands set terminal pslatex
8524: @c ?set terminal pslatex
8525: @c ?set term pslatex
8526: @c ?terminal pslatex
8527: @c ?term pslatex
8528: @cindex pslatex
8529: @tmindex pslatex
8530:
8531:
8532: @c ?commands set terminal pstex
8533: @c ?set terminal pstex
8534: @c ?set term pstex
8535: @c ?terminal pstex
8536: @c ?term pstex
8537: @cindex pstex
8538: @tmindex pstex
8539:
8540:
8541: The `pslatex` and `pstex` drivers generate output for further processing by
8542: LaTeX and TeX, respectively. Figures generated by `pstex` can be included
8543: in any plain-based format (including LaTeX).
8544:
8545: Syntax:
8546: @example
8547: set terminal pslatex | |pstex @{<color>@} @{<dashed>@} @{<rotate>@}
8548: @{auxfile@} @{<font_size>@}
8549:
8550: @end example
8551:
8552: <color> is either `color` or `monochrome`. <rotate> is either `rotate` or
8553: `norotate` and determines if the y-axis label is rotated. <font_size> is
8554: used to scale the font from its usual size.
8555:
8556: If `auxfile` is specified, it directs the driver to put the PostScript
8557: commands into an auxiliary file instead of directly into the LaTeX file.
8558: This is useful if your pictures are large enough that dvips cannot handle
8559: them. The name of the auxiliary PostScript file is derived from the name of
8560: the TeX file given on the @ref{output} command; it is determined by replacing
8561: the trailing `.tex` (actually just the final extent in the file name) with
8562: `.ps` in the output file name, or, if the TeX file has no extension, `.ps`
8563: is appended. Remember to close the file before leaving `gnuplot`.
8564:
8565: All drivers for LaTeX offer a special way of controlling text positioning:
8566: If any text string begins with '@{', you also need to include a '@}' at the
8567: end of the text, and the whole text will be centered both horizontally
8568: and vertically by LaTeX. --- If the text string begins with '[', you need
8569: to continue it with: a position specification (up to two out of t,b,l,r),
8570: ']@{', the text itself, and finally, '@}'. The text itself may be anything
8571: LaTeX can typeset as an LR-box. \\rule@{@}@{@}'s may help for best positioning.
8572:
8573: Examples:
8574: @example
8575: set term pslatex monochrome dashed rotate # set to defaults
8576: @end example
8577:
8578: To write the PostScript commands into the file "foo.ps":
8579: @example
8580: set term pslatex auxfile
8581: set output "foo.tex"; plot ...: set output
8582: @end example
8583:
8584: About label positioning:
8585: Use gnuplot defaults (mostly sensible, but sometimes not really best):
8586: @example
8587: set title '\\LaTeX\\ -- $ \\gamma $'
8588: @end example
8589:
8590: Force centering both horizontally and vertically:
8591: @example
8592: set label '@{\\LaTeX\\ -- $ \\gamma $@}' at 0,0
8593: @end example
8594:
8595: Specify own positioning (top here):
8596: @example
8597: set xlabel '[t]@{\\LaTeX\\ -- $ \\gamma $@}'
8598: @end example
8599:
8600: The other label -- account for long ticlabels:
8601: @example
8602: set ylabel '[r]@{\\LaTeX\\ -- $ \\gamma $\\rule@{7mm@}@{0pt@}'
8603:
8604: @end example
8605:
8606: Linewidths and pointsizes may be changed with @ref{linestyle}."
8607:
8608: @node pstricks, qms, pslatex_and_pstex, terminal
8609: @subsubsection pstricks
8610:
8611: @c ?commands set terminal pstricks
8612: @c ?set terminal pstricks
8613: @c ?set term pstricks
8614: @c ?terminal pstricks
8615: @c ?term pstricks
8616: @cindex pstricks
8617: @tmindex pstricks
8618:
8619:
8620: The `pstricks` driver is intended for use with the "pstricks.sty" macro
8621: package for LaTeX. It is an alternative to the `eepic` and `latex` drivers.
8622: You need "pstricks.sty", and, of course, a printer that understands
8623: PostScript, or a converter such as Ghostscript.
8624:
8625: PSTricks is available via anonymous ftp from the /pub directory at
8626: Princeton.EDU. This driver definitely does not come close to using the full
8627: capability of the PSTricks package.
8628:
8629: Syntax:
8630: @example
8631: set terminal pstricks @{hacktext | nohacktext@} @{unit | nounit@}
8632:
8633: @end example
8634:
8635: The first option invokes an ugly hack that gives nicer numbers; the second
8636: has to do with plot scaling. The defaults are `hacktext` and `nounit`."
8637:
8638: @node qms, regis, pstricks, terminal
8639: @subsubsection qms
8640:
8641: @c ?commands set terminal qms
8642: @c ?set terminal qms
8643: @c ?set term qms
8644: @c ?terminal qms
8645: @c ?term qms
8646: @cindex qms
8647: @tmindex qms
8648:
8649:
8650: The `qms` terminal driver supports the QMS/QUIC Laser printer, the Talaris
8651: 1200 and others. It has no options."
8652:
8653: @node regis, sun, qms, terminal
8654: @subsubsection regis
8655:
8656: @c ?commands set terminal regis
8657: @c ?set terminal regis
8658: @c ?set term regis
8659: @c ?terminal regis
8660: @c ?term regis
8661: @cindex regis
8662: @tmindex regis
8663:
8664:
8665: The `regis` terminal device generates output in the REGIS graphics language.
8666: It has the option of using 4 (the default) or 16 colors.
8667:
8668: Syntax:
8669: @example
8670: set terminal regis @{4 | 16@}"
8671:
8672: @end example
8673:
8674: @node sun, tek410x, regis, terminal
8675: @subsubsection sun
8676:
8677: @c ?commands set terminal sun
8678: @c ?set terminal sun
8679: @c ?set term sun
8680: @c ?terminal sun
8681: @c ?term sun
8682: @cindex sun
8683: @tmindex sun
8684:
8685:
8686: The `sun` terminal driver supports the SunView window system. It has no
8687: options."
8688:
8689: @node tek410x, table, sun, terminal
8690: @subsubsection tek410x
8691:
8692: @c ?commands set terminal tek410x
8693: @c ?set terminal tek410x
8694: @c ?set term tek410x
8695: @c ?terminal tek410x
8696: @c ?term tek410x
8697: @cindex tek410x
8698: @tmindex tek410x
8699:
8700:
8701: The `tek410x` terminal driver supports the 410x and 420x family of Tektronix
8702: terminals. It has no options."
8703:
8704: @node table, tek40, tek410x, terminal
8705: @subsubsection table
8706:
8707: @c ?commands set terminal table
8708: @c ?set terminal table
8709: @c ?set term table
8710: @c ?terminal table
8711: @c ?term table
8712: @cindex table
8713: @tmindex table
8714:
8715:
8716: Instead of producing a graph, the `table` terminal prints out the points on
8717: which a graph would be based, i.e., the results of processing the @ref{plot} or
8718: `splot` command, in a multicolumn ASCII table of X Y @{Z@} R values. The
8719: character R takes on one of three values: "i" if the point is in the active
8720: range, "o" if it is out-of-range, or "u" if it is undefined. The data
8721: format is determined by the format of the axis labels (see `set format`).
8722:
8723: For those times when you want the numbers, you can display them on the
8724: screen or save them to a file. This can be useful if you want to generate
8725: contours and then save them for further use, perhaps for plotting with
8726: @ref{plot}; see @ref{contour} for an example. The same method can be used to
8727: save interpolated data (see @ref{samples} and @ref{dgrid3d})."
8728:
8729: @node tek40, texdraw, table, terminal
8730: @subsubsection tek40
8731:
8732: @c ?commands set terminal tek40xx
8733: @c ?set terminal tek40xx
8734: @c ?set term tek40xx
8735: @c ?terminal tek40xx
8736: @c ?terminal tek40xx
8737: @cindex tek40
8738: @tmindex tek40
8739:
8740:
8741: @c ?commands set terminal vttek
8742: @c ?set terminal vttek
8743: @c ?set term vttek
8744: @c ?terminal vttek
8745: @c ?term vttek
8746: @cindex vttek
8747: @tmindex vttek
8748:
8749:
8750: @c ?commands set terminal kc-tek40xx
8751: @c ?set terminal kc-tek40xx
8752: @c ?set term kc-tek40xx
8753: @c ?terminal kc-tek40xx
8754: @c ?term kc-tek40xx
8755: @cindex kc-tek40xx
8756: @tmindex kc-tek40xx
8757:
8758:
8759: @c ?commands set terminal km-tek40xx
8760: @c ?set terminal km-tek40xx
8761: @c ?set term km-tek40xx
8762: @c ?terminal km-tek40xx
8763: @c ?term km-tek40xx
8764: @cindex km-tek40xx
8765: @tmindex km-tek40xx
8766:
8767:
8768: @c ?commands set terminal selanar
8769: @c ?set terminal selanar
8770: @c ?set term selanar
8771: @c ?terminal selanar
8772: @c ?term selanar
8773: @cindex selanar
8774: @tmindex selanar
8775:
8776:
8777: @c ?commands set terminal bitgraph
8778: @c ?set terminal bitgraph
8779: @c ?set term bitgraph
8780: @c ?terminal bitgraph
8781: @c ?term bitgraph
8782: @cindex bitgraph
8783: @tmindex bitgraph
8784:
8785:
8786: This family of terminal drivers supports a variety of VT-like terminals.
8787: `tek40xx` supports Tektronix 4010 and others as well as most TEK emulators;
8788: `vttek` supports VT-like tek40xx terminal emulators; `kc-tek40xx` supports
8789: MS-DOS Kermit Tek4010 terminal emulators in color: `km-tek40xx` supports them
8790: in monochrome; `selanar` supports Selanar graphics; and `bitgraph` supports
8791: BBN Bitgraph terminals. None have any options."
8792:
8793: @node texdraw, tgif, tek40, terminal
8794: @subsubsection texdraw
8795:
8796: @c ?commands set terminal texdraw
8797: @c ?set terminal texdraw
8798: @c ?set term texdraw
8799: @c ?terminal texdraw
8800: @c ?term texdraw
8801: @cindex texdraw
8802: @tmindex texdraw
8803:
8804:
8805: The `texdraw` terminal driver supports the LaTeX texdraw environment. It is
8806: intended for use with "texdraw.sty" and "texdraw.tex" in the texdraw package.
8807:
8808: It has no options."
8809:
8810: @node tgif, tkcanvas, texdraw, terminal
8811: @subsubsection tgif
8812:
8813: @c ?commands set terminal tgif
8814: @c ?set terminal tgif
8815: @c ?set term tgif
8816: @c ?terminal tgif
8817: @c ?term tgif
8818: @cindex tgif
8819: @tmindex tgif
8820:
8821:
8822: Tgif is an X11-based drawing tool---it has nothing to do with GIF.
8823:
8824: The `tgif` driver supports different pointsizes (with @ref{pointsize}),
8825: different label fonts and font sizes (e.g. `set label "Hallo" at x,y font
8826: "Helvetica,34"`) and multiple graphs on the page. The proportions of the
8827: axes are not changed.
8828:
8829: Syntax:
8830: @example
8831: set terminal tgif @{portrait | landscape@} @{<[x,y]>@}
8832: @{solid | dashed@}
8833: @{"<fontname>"@} @{<fontsize>@}
8834:
8835: @end example
8836:
8837: where <[x,y]> specifies the number of graphs in the x and y directions on the
8838: page, "<fontname>" is the name of a valid PostScript font, and <fontsize>
8839: specifies the size of the PostScript font. Defaults are `portrait`, `[1,1]`,
8840: `dashed`, `"Helvetica"`, and `18`.
8841:
8842: The `solid` option is usually prefered if lines are colored, as they often
8843: are in the editor. Hardcopy will be black-and-white, so `dashed` should be
8844: chosen for that.
8845:
8846: Multiplot is implemented in two different ways.
8847:
8848: The first multiplot implementation is the standard gnuplot multiplot feature:
8849:
8850: @example
8851: set terminal tgif
8852: set output "file.obj"
8853: set multiplot
8854: set origin x01,y01
8855: set size xs,ys
8856: plot ...
8857: ...
8858: set origin x02,y02
8859: plot ...
8860: set nomultiplot
8861:
8862: @end example
8863:
8864: See @ref{multiplot} for further information.
8865:
8866: The second version is the [x,y] option for the driver itself. The advantage
8867: of this implementation is that everything is scaled and placed automatically
8868: without the need for setting origins and sizes; the graphs keep their natural
8869: x/y proportions of 3/2 (or whatever is fixed by @ref{size}).
8870:
8871: If both multiplot methods are selected, the standard method is chosen and a
8872: warning message is given.
8873:
8874: Examples of single plots (or standard multiplot):
8875: @example
8876: set terminal tgif # defaults
8877: set terminal tgif "Times-Roman" 24
8878: set terminal tgif landscape
8879: set terminal tgif landscape solid
8880:
8881: @end example
8882:
8883: Examples using the built-in multiplot mechanism:
8884: @example
8885: set terminal tgif portrait [2,4] # portrait; 2 plots in the x-
8886: # and 4 in the y-direction
8887: set terminal tgif [1,2] # portrait; 1 plot in the x-
8888: # and 2 in the y-direction
8889: set terminal tgif landscape [3,3] # landscape; 3 plots in both
8890: # directions"
8891:
8892: @end example
8893:
8894: @node tkcanvas, tpic, tgif, terminal
8895: @subsubsection tkcanvas
8896:
8897: @c ?commands set terminal tkcanvas
8898: @c ?set terminal tkcanvas
8899: @c ?set term tkcanvas
8900: @c ?terminal tkcanvas
8901: @c ?term tkcanvas
8902: @cindex tkcanvas
8903: @tmindex tkcanvas
8904:
8905:
8906: This terminal driver generates Tk canvas widget commands based on Tcl/Tk
8907: (default) or Perl. To use it, rebuild `gnuplot` (after uncommenting or
8908: inserting the appropriate line in "term.h"), then
8909:
8910: @example
8911: gnuplot> set term tkcanvas @{perltk@} @{interactive@}
8912: gnuplot> set output 'plot.file'
8913:
8914: @end example
8915:
8916: After invoking "wish", execute the following sequence of Tcl/Tk commands:
8917:
8918: @example
8919: % source plot.file
8920: % canvas .c
8921: % pack .c
8922: % gnuplot .c
8923:
8924: @end example
8925:
8926: Or, for Perl/Tk use a program like this:
8927:
8928: @example
8929: use Tk;
8930: my $top = MainWindow->new;
8931: my $c = $top->Canvas;
8932: $c->pack();
8933: do "plot.pl";
8934: gnuplot->($c);
8935: MainLoop;
8936:
8937: @end example
8938:
8939: The code generated by `gnuplot` creates a procedure called "gnuplot"
8940: that takes the name of a canvas as its argument. When the procedure is
8941: called, it clears the canvas, finds the size of the canvas and draws the plot
8942: in it, scaled to fit.
8943:
8944: For 2-dimensional plotting (@ref{plot}) two additional procedures are defined:
8945: "gnuplot_plotarea" will return a list containing the borders of the plotting
8946: area "xleft, xright, ytop, ybot" in canvas screen coordinates, while the ranges
8947: of the two axes "x1min, x1max, y1min, y1max, x2min, x2max, y2min, y2max" in plot
8948: coordinates can be obtained calling "gnuplot_axisranges".
8949: If the "interactive" option is specified, mouse clicking on a line segment
8950: will print the coordinates of its midpoint to stdout. Advanced actions
8951: can happen instead if the user supplies a procedure named
8952: "user_gnuplot_coordinates", which takes the following arguments:
8953: "win id x1s y1s x2s y2s x1e y1e x2e y2e x1m y1m x2m y2m",
8954: the name of the canvas and the id of the line segment followed by the
8955: coordinates of its start and end point in the two possible axis ranges; the
8956: coordinates of the midpoint are only filled for logarithmic axes.
8957:
8958: The current version of `tkcanvas` supports neither @ref{multiplot} nor @ref{replot}."
8959:
8960: @node tpic, x11, tkcanvas, terminal
8961: @subsubsection tpic
8962:
8963: @c ?commands set terminal tpic
8964: @c ?set terminal tpic
8965: @c ?set term tpic
8966: @c ?terminal tpic
8967: @c ?term tpic
8968: @cindex tpic
8969: @tmindex tpic
8970:
8971:
8972: The `tpic` terminal driver supports the LaTeX picture environment with tpic
8973: \\specials. It is an alternative to the `latex` and `eepic` terminal drivers.
8974: Options are the point size, line width, and dot-dash interval.
8975:
8976: Syntax:
8977: @example
8978: set terminal tpic <pointsize> <linewidth> <interval>
8979:
8980: @end example
8981:
8982: where @ref{pointsize} and `linewidth` are integers in milli-inches and `interval`
8983: is a float in inches. If a non-positive value is specified, the default is
8984: chosen: pointsize = 40, linewidth = 6, interval = 0.1.
8985:
8986: All drivers for LaTeX offer a special way of controlling text positioning:
8987: If any text string begins with '@{', you also need to include a '@}' at the
8988: end of the text, and the whole text will be centered both horizontally
8989: and vertically by LaTeX. --- If the text string begins with '[', you need
8990: to continue it with: a position specification (up to two out of t,b,l,r),
8991: ']@{', the text itself, and finally, '@}'. The text itself may be anything
8992: LaTeX can typeset as an LR-box. \\rule@{@}@{@}'s may help for best positioning.
8993:
8994: Examples:
8995: About label positioning:
8996: Use gnuplot defaults (mostly sensible, but sometimes not really best):
8997: @example
8998: set title '\\LaTeX\\ -- $ \\gamma $'
8999: @end example
9000:
9001: Force centering both horizontally and vertically:
9002: @example
9003: set label '@{\\LaTeX\\ -- $ \\gamma $@}' at 0,0
9004: @end example
9005:
9006: Specify own positioning (top here):
9007: @example
9008: set xlabel '[t]@{\\LaTeX\\ -- $ \\gamma $@}'
9009: @end example
9010:
9011: The other label -- account for long ticlabels:
9012: @example
9013: set ylabel '[r]@{\\LaTeX\\ -- $ \\gamma $\\rule@{7mm@}@{0pt@}'"
9014:
9015: @end example
9016:
9017: @node x11, xlib, tpic, terminal
9018: @subsubsection x11
9019:
9020: @c ?commands set terminal x11
9021: @c ?set terminal x11
9022: @c ?set term x11
9023: @c ?terminal x11
9024: @c ?term x11
9025: @cindex x11
9026:
9027: @cindex X11
9028:
9029: `gnuplot` provides the `x11` terminal type for use with X servers. This
9030: terminal type is set automatically at startup if the `DISPLAY` environment
9031: variable is set, if the `TERM` environment variable is set to `xterm`, or
9032: if the `-display` command line option is used.
9033:
9034: Syntax:
9035: @example
9036: set terminal x11 @{reset@} @{<n>@}
9037:
9038: @end example
9039:
9040: Multiple plot windows are supported: `set terminal x11 <n>` directs the
9041: output to plot window number n. If n>0, the terminal number will be
9042: appended to the window title and the icon will be labeled `gplt <n>`.
9043: The active window may distinguished by a change in cursor (from default
9044: to crosshair.)
9045:
9046: Plot windows remain open even when the `gnuplot` driver is changed to a
9047: different device. A plot window can be closed by pressing the letter q
9048: while that window has input focus, or by choosing `close` from a window
9049: manager menu. All plot windows can be closed by specifying @ref{reset}, which
9050: actually terminates the subprocess which maintains the windows (unless
9051: `-persist` was specified).
9052:
9053: Plot windows will automatically be closed at the end of the session
9054: unless the `-persist` option was given.
9055:
9056: The size or aspect ratio of a plot may be changed by resizing the `gnuplot`
9057: window.
9058:
9059: Linewidths and pointsizes may be changed from within `gnuplot` with
9060: @ref{linestyle}.
9061:
9062: For terminal type `x11`, `gnuplot` accepts (when initialized) the standard
9063: X Toolkit options and resources such as geometry, font, and name from the
9064: command line arguments or a configuration file. See the X(1) man page
9065: (or its equivalent) for a description of such options.
9066:
9067: A number of other `gnuplot` options are available for the `x11` terminal.
9068: These may be specified either as command-line options when `gnuplot` is
9069: invoked or as resources in the configuration file "/.Xdefaults". They are
9070: set upon initialization and cannot be altered during a `gnuplot` session.
9071:
9072:
9073: @noindent --- COMMAND-LINE_OPTIONS ---
9074:
9075: @c ?commands set terminal x11 command-line-options
9076: @c ?set terminal x11 command-line-options
9077: @c ?set term x11 command-line-options
9078: @c ?x11 command-line-options
9079: @cindex command-line-options
9080:
9081: In addition to the X Toolkit options, the following options may be specified
9082: on the command line when starting `gnuplot` or as resources in your
9083: ".Xdefaults" file:
9084:
9085: @example
9086: `-clear` requests that the window be cleared momentarily before a
9087: new plot is displayed.
9088: `-gray` requests grayscale rendering on grayscale or color displays.
9089: (Grayscale displays receive monochrome rendering by default.)
9090: `-mono` forces monochrome rendering on color displays.
9091: `-persist` plot windows survive after main gnuplot program exits
9092: `-raise` raise plot window after each plot
9093: `-noraise` do not raise plot window after each plot
9094: `-tvtwm` requests that geometry specifications for position of the
9095: window be made relative to the currently displayed portion
9096: of the virtual root.
9097:
9098: @end example
9099:
9100: The options are shown above in their command-line syntax. When entered as
9101: resources in ".Xdefaults", they require a different syntax.
9102:
9103: Example:
9104: @example
9105: gnuplot*gray: on
9106:
9107: @end example
9108:
9109: `gnuplot` also provides a command line option (`-pointsize <v>`) and a
9110: resource, `gnuplot*pointsize: <v>`, to control the size of points plotted
9111: with the `points` plotting style. The value `v` is a real number (greater
9112: than 0 and less than or equal to ten) used as a scaling factor for point
9113: sizes. For example, `-pointsize 2` uses points twice the default size, and
9114: `-pointsize 0.5` uses points half the normal size.
9115:
9116:
9117: @noindent --- MONOCHOME_OPTIONS ---
9118:
9119: @c ?commands set terminal x11 monochrome_options
9120: @c ?set terminal x11 monochrome_options
9121: @c ?set term x11 monochrome_options
9122: @c ?x11 monochrome_options
9123: @cindex monochrome_options
9124:
9125: For monochrome displays, `gnuplot` does not honor foreground or background
9126: colors. The default is black-on-white. `-rv` or `gnuplot*reverseVideo: on`
9127: requests white-on-black.
9128:
9129:
9130:
9131: @noindent --- COLOR_RESOURCES ---
9132:
9133: @c ?commands set terminal x11 color_resources
9134: @c ?set terminal x11 color_resources
9135: @c ?set term x11 color_resources
9136: @c ?x11 color_resources
9137: @cindex color_resources
9138:
9139: For color displays, `gnuplot` honors the following resources (shown here
9140: with their default values) or the greyscale resources. The values may be
9141: color names as listed in the X11 rgb.txt file on your system, hexadecimal
9142: RGB color specifications (see X11 documentation), or a color name followed
9143: by a comma and an `intensity` value from 0 to 1. For example, `blue, 0.5`
9144: means a half intensity blue.
9145:
9146: @example
9147: gnuplot*background: white
9148: gnuplot*textColor: black
9149: gnuplot*borderColor: black
9150: gnuplot*axisColor: black
9151: gnuplot*line1Color: red
9152: gnuplot*line2Color: green
9153: gnuplot*line3Color: blue
9154: gnuplot*line4Color: magenta
9155: gnuplot*line5Color: cyan
9156: gnuplot*line6Color: sienna
9157: gnuplot*line7Color: orange
9158: gnuplot*line8Color: coral
9159:
9160: @end example
9161:
9162:
9163: The command-line syntax for these is, for example,
9164:
9165: Example:
9166: @example
9167: gnuplot -background coral
9168:
9169: @end example
9170:
9171:
9172:
9173: @noindent --- GRAYSCALE_RESOURCES ---
9174:
9175: @c ?commands set terminal x11 grayscale_resources
9176: @c ?set terminal x11 grayscale_resources
9177: @c ?set term x11 grayscale_resources
9178: @c ?x11 grayscale_resources
9179: @cindex grayscale_resources
9180:
9181: When `-gray` is selected, `gnuplot` honors the following resources for
9182: grayscale or color displays (shown here with their default values). Note
9183: that the default background is black.
9184:
9185: @example
9186: gnuplot*background: black
9187: gnuplot*textGray: white
9188: gnuplot*borderGray: gray50
9189: gnuplot*axisGray: gray50
9190: gnuplot*line1Gray: gray100
9191: gnuplot*line2Gray: gray60
9192: gnuplot*line3Gray: gray80
9193: gnuplot*line4Gray: gray40
9194: gnuplot*line5Gray: gray90
9195: gnuplot*line6Gray: gray50
9196: gnuplot*line7Gray: gray70
9197: gnuplot*line8Gray: gray30
9198:
9199: @end example
9200:
9201:
9202:
9203:
9204: @noindent --- LINE_RESOURCES ---
9205:
9206: @c ?commands set terminal x11 line_resources
9207: @c ?set terminal x11 line_resources
9208: @c ?set term x11 line_resources
9209: @c ?x11 line_resources
9210: @cindex line_resources
9211:
9212: `gnuplot` honors the following resources for setting the width (in pixels) of
9213: plot lines (shown here with their default values.) 0 or 1 means a minimal
9214: width line of 1 pixel width. A value of 2 or 3 may improve the appearance of
9215: some plots.
9216:
9217: @example
9218: gnuplot*borderWidth: 2
9219: gnuplot*axisWidth: 0
9220: gnuplot*line1Width: 0
9221: gnuplot*line2Width: 0
9222: gnuplot*line3Width: 0
9223: gnuplot*line4Width: 0
9224: gnuplot*line5Width: 0
9225: gnuplot*line6Width: 0
9226: gnuplot*line7Width: 0
9227: gnuplot*line8Width: 0
9228:
9229: @end example
9230:
9231:
9232: `gnuplot` honors the following resources for setting the dash style used for
9233: plotting lines. 0 means a solid line. A two-digit number `jk` (`j` and `k`
9234: are >= 1 and <= 9) means a dashed line with a repeated pattern of `j` pixels
9235: on followed by `k` pixels off. For example, '16' is a "dotted" line with one
9236: pixel on followed by six pixels off. More elaborate on/off patterns can be
9237: specified with a four-digit value. For example, '4441' is four on, four off,
9238: four on, one off. The default values shown below are for monochrome displays
9239: or monochrome rendering on color or grayscale displays. For color displays,
9240: the default for each is 0 (solid line) except for `axisDashes` which defaults
9241: to a '16' dotted line.
9242:
9243: @example
9244: gnuplot*borderDashes: 0
9245: gnuplot*axisDashes: 16
9246: gnuplot*line1Dashes: 0
9247: gnuplot*line2Dashes: 42
9248: gnuplot*line3Dashes: 13
9249: gnuplot*line4Dashes: 44
9250: gnuplot*line5Dashes: 15
9251: gnuplot*line6Dashes: 4441
9252: gnuplot*line7Dashes: 42
9253: gnuplot*line8Dashes: 13
9254:
9255: @end example
9256:
9257:
9258: @node xlib, , x11, terminal
9259: @subsubsection xlib
9260:
9261: @c ?commands set terminal xlib
9262: @c ?set terminal xlib
9263: @c ?set term xlib
9264: @c ?terminal xlib
9265: @c ?term xlib
9266: @cindex xlib
9267: @tmindex xlib
9268:
9269:
9270: The `xlib` terminal driver supports the X11 Windows System. It generates
9271: gnulib_x11 commands. `set term x11` behaves similarly to `set terminal xlib;
9272: set output "|gnuplot_x11"`. `xlib` has no options, but see `x11`."
9273:
9274: @node tics, ticslevel, terminal, set-show
9275: @subsection tics
9276:
9277: @c ?commands set tics
9278: @c ?commands show tics
9279: @c ?set tics
9280: @c ?show tics
9281: @cindex tics
9282: @opindex tics
9283:
9284:
9285: The `set tics` command can be used to change the tics to be drawn outwards.
9286:
9287: Syntax:
9288: @example
9289: set tics @{<direction>@}
9290: show tics
9291:
9292: @end example
9293:
9294: where <direction> may be `in` (the default) or `out`.
9295:
9296: See also @ref{xtics} for more control of major (labelled) tic marks and @ref{mxtics} for control of minor tic marks.
9297:
9298: @node ticslevel, ticscale, tics, set-show
9299: @subsection ticslevel
9300:
9301: @c ?commands set ticslevel
9302: @c ?commands show ticslevel
9303: @c ?set ticslevel
9304: @c ?show ticslevel
9305: @cindex ticslevel
9306: @opindex ticslevel
9307:
9308:
9309: Using `splot`, one can adjust the relative height of the vertical (Z) axis
9310: using @ref{ticslevel}. The numeric argument provided specifies the location
9311: of the bottom of the scale (as a fraction of the z-range) above the xy-plane.
9312: The default value is 0.5. Negative values are permitted, but tic labels on
9313: the three axes may overlap.
9314:
9315: To place the xy-plane at a position 'pos' on the z-axis, @ref{ticslevel} should
9316: be set equal to (pos - zmin) / (zmin - zmax).
9317:
9318: Syntax:
9319: @example
9320: set ticslevel @{<level>@}
9321: show tics
9322:
9323: @end example
9324:
9325: See also @ref{view}.
9326:
9327: @node ticscale, timestamp, ticslevel, set-show
9328: @subsection ticscale
9329:
9330: @c ?commands set ticscale
9331: @c ?commands show ticscale
9332: @c ?set ticscale
9333: @c ?show ticscale
9334: @cindex ticscale
9335: @opindex ticscale
9336:
9337:
9338: The size of the tic marks can be adjusted with @ref{ticscale}.
9339:
9340: Syntax:
9341: @example
9342: set ticscale @{<major> @{<minor>@}@}
9343: show tics
9344:
9345: @end example
9346:
9347: If <minor> is not specified, it is 0.5*<major>. The default size is 1.0 for
9348: major tics and 0.5 for minor tics. Note that it is possible to have the tic
9349: marks pointing outward by specifying a negative size.
9350:
9351: @node timestamp, timefmt, ticscale, set-show
9352: @subsection timestamp
9353:
9354: @c ?commands set timestamp
9355: @c ?commands set time
9356: @c ?commands set notimestamp
9357: @c ?commands show timestamp
9358: @c ?set timestamp
9359: @c ?set time
9360: @c ?set notimestamp
9361: @c ?show timestamp
9362: @cindex timestamp
9363: @opindex timestamp
9364:
9365:
9366: @cindex notimestamp
9367:
9368: The command @ref{timestamp} places the time and date of the plot in the left
9369: margin.
9370:
9371: Syntax:
9372: @example
9373: set timestamp @{"<format>"@} @{top|bottom@} @{@{no@}rotate@}
9374: @{<xoff>@}@{,<yoff>@} @{"<font>"@}
9375: set notimestamp
9376: show timestamp
9377:
9378: @end example
9379:
9380: The format string allows you to choose the format used to write the date and
9381: time. Its default value is what asctime() uses: "%a %b %d %H:%M:%S %Y"
9382: (weekday, month name, day of the month, hours, minutes, seconds, four-digit
9383: year). With `top` or `bottom` you can place the timestamp at the top or
9384: bottom of the left margin (default: bottom). `rotate` lets you write the
9385: timestamp vertically, if your terminal supports vertical text. The constants
9386: <xoff> and <off> are offsets from the default position given in character
9387: screen coordinates. <font> is used to specify the font with which the time
9388: is to be written.
9389:
9390: The abbreviation `time` may be used in place of @ref{timestamp}.
9391:
9392: Example:
9393: @example
9394: set timestamp "%d/%m/%y %H:%M" 80,-2 "Helvetica"
9395:
9396: @end example
9397:
9398: See @ref{timefmt} for more information about time format strings.
9399:
9400: @node timefmt, title_, timestamp, set-show
9401: @subsection timefmt
9402:
9403: @c ?commands set timefmt
9404: @c ?commands show timefmt
9405: @c ?set timefmt
9406: @c ?show timefmt
9407: @cindex timefmt
9408: @opindex timefmt
9409:
9410:
9411: This command applies to timeseries where data are composed of dates/times.
9412: It has no meaning unless the command `set xdata time` is given also.
9413:
9414: Syntax:
9415: @example
9416: set timefmt "<format string>"
9417: show timefmt
9418:
9419: @end example
9420:
9421: The string argument tells `gnuplot` how to read timedata from the datafile.
9422: The valid formats are:
9423:
9424:
9425: @example
9426: Format Explanation
9427: %d day of the month, 1--31
9428: %m month of the year, 1--12
9429: %y year, 0--99
9430: %Y year, 4-digit
9431: %j day of the year, 1--365
9432: %H hour, 0--24
9433: %M minute, 0--60
9434: %S second, 0--60
9435: %b three-character abbreviation of the name of the month
9436: %B name of the month
9437:
9438: @end example
9439:
9440: Any character is allowed in the string, but must match exactly. \t (tab) is
9441: recognized. Backslash-octals (\nnn) are converted to char. If there is no
9442: separating character between the time/date elements, then %d, %m, %y, %H, %M
9443: and %S read two digits each, %Y reads four digits and %j reads three digits.
9444: %b requires three characters, and %B requires as many as it needs.
9445:
9446: Spaces are treated slightly differently. A space in the string stands for
9447: zero or more whitespace characters in the file. That is, "%H %M" can be used
9448: to read "1220" and "12 20" as well as "12 20".
9449:
9450: Each set of non-blank characters in the timedata counts as one column in the
9451: `using n:n` specification. Thus `11:11 25/12/76 21.0` consists of three
9452: columns. To avoid confusion, `gnuplot` requires that you provide a complete
9453: @ref{using} specification if your file contains timedata.
9454:
9455: Since `gnuplot` cannot read non-numerical text, if the date format includes
9456: the day or month in words, the format string must exclude this text. But
9457: it can still be printed with the "%a", "%A", "%b", or "%B" specifier: see
9458: `set format` for more details about these and other options for printing
9459: timedata. (`gnuplot` will determine the proper month and weekday from the
9460: numerical values.)
9461:
9462: See also @ref{xdata} and `Time/date` for more information.
9463:
9464: Example:
9465: @example
9466: set timefmt "%d/%m/%Y\t%H:%M"
9467: @end example
9468:
9469: tells `gnuplot` to read date and time separated by tab. (But look closely at
9470: your data---what began as a tab may have been converted to spaces somewhere
9471: along the line; the format string must match what is actually in the file.)
9472: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/timedat.html,Time Data Demo }
9473:
9474: @node title_, tmargin, timefmt, set-show
9475: @subsection title
9476:
9477: @c ?commands set title
9478: @c ?commands show title
9479: @c ?set title
9480: @c ?show title
9481: @cindex title
9482: @opindex title
9483:
9484:
9485: The `set title` command produces a plot title that is centered at the top of
9486: the plot. `set title` is a special case of @ref{label}.
9487:
9488: Syntax:
9489: @example
9490: set title @{"<title-text>"@} @{<xoff>@}@{,<yoff>@} @{"<font>,@{<size>@}"@}
9491: show title
9492:
9493: @end example
9494:
9495: Specifying constants <xoff> or <yoff> as optional offsets for the title will
9496: move the title <xoff> or <yoff> character screen coordinates (not graph
9497: coordinates). For example, "`set title ,-1`" will change only the y offset
9498: of the title, moving the title down by roughly the height of one character.
9499:
9500: <font> is used to specify the font with which the title is to be written;
9501: the units of the font <size> depend upon which terminal is used.
9502:
9503: `set title` with no parameters clears the title.
9504:
9505: See `syntax` for details about the processing of backslash sequences and
9506: the distinction between single- and double-quotes.
9507:
9508: @node tmargin, trange, title_, set-show
9509: @subsection tmargin
9510:
9511: @c ?commands set tmargin
9512: @c ?set tmargin
9513: @cindex tmargin
9514: @opindex tmargin
9515:
9516:
9517: The command @ref{tmargin} sets the size of the top margin. Please see
9518: @ref{margin} for details.
9519:
9520: @node trange, urange, tmargin, set-show
9521: @subsection trange
9522:
9523: @c ?commands set trange
9524: @c ?commands show trange
9525: @c ?set trange
9526: @c ?show trange
9527: @cindex trange
9528: @opindex trange
9529:
9530:
9531: The @ref{trange} command sets the parametric range used to compute x and y
9532: values when in parametric or polar modes. Please see @ref{xrange} for
9533: details.
9534:
9535: @node urange, variables, trange, set-show
9536: @subsection urange
9537:
9538: @c ?commands set urange
9539: @c ?commands show urange
9540: @c ?set urange
9541: @c ?show urange
9542: @cindex urange
9543: @opindex urange
9544:
9545:
9546: The @ref{urange} and @ref{vrange} commands set the parametric ranges used
9547: to compute x, y, and z values when in `splot` parametric mode. Please see
9548: @ref{xrange} for details.
9549:
9550: @node variables, version, urange, set-show
9551: @subsection variables
9552:
9553: @c ?commands show variables
9554: @c ?show variables
9555: The @ref{variables} command lists all user-defined variables and their
9556: values.
9557:
9558: Syntax:
9559: @example
9560: show variables
9561:
9562: @end example
9563:
9564: @node version, view, variables, set-show
9565: @subsection version
9566:
9567: @c ?show version
9568: The @ref{version} command lists the version of gnuplot being run, its last
9569: modification date, the copyright holders, and email addresses for the FAQ,
9570: the info-gnuplot mailing list, and reporting bugs--in short, the information
9571: listed on the screen when the program is invoked interactively.
9572:
9573: Syntax:
9574: @example
9575: show version @{long@}
9576:
9577: @end example
9578:
9579: When the `long` option is given, it also lists the operating system, the
9580: compilation options used when `gnuplot` was installed, the location of the
9581: help file, and (again) the useful email addresses.
9582:
9583: @node view, vrange, version, set-show
9584: @subsection view
9585:
9586: @c ?commands set view
9587: @c ?commands show view
9588: @c ?set view
9589: @c ?show view
9590: @cindex view
9591: @opindex view
9592:
9593:
9594: The @ref{view} command sets the viewing angle for `splot`s. It controls how
9595: the 3-d coordinates of the plot are mapped into the 2-d screen space. It
9596: provides controls for both rotation and scaling of the plotted data, but
9597: supports orthographic projections only.
9598:
9599: Syntax:
9600: @example
9601: set view <rot_x> @{,@{<rot_z>@}@{,@{<scale>@}@{,<scale_z>@}@}@}
9602: show view
9603:
9604: @end example
9605:
9606: where <rot_x> and <rot_z> control the rotation angles (in degrees) in a
9607: virtual 3-d coordinate system aligned with the screen such that initially
9608: (that is, before the rotations are performed) the screen horizontal axis is
9609: x, screen vertical axis is y, and the axis perpendicular to the screen is z.
9610: The first rotation applied is <rot_x> around the x axis. The second rotation
9611: applied is <rot_z> around the new z axis.
9612:
9613: <rot_x> is bounded to the [0:180] range with a default of 60 degrees, while
9614: <rot_z> is bounded to the [0:360] range with a default of 30 degrees.
9615: <scale> controls the scaling of the entire `splot`, while <scale_z> scales
9616: the z axis only. Both scales default to 1.0.
9617:
9618: Examples:
9619: @example
9620: set view 60, 30, 1, 1
9621: set view ,,0.5
9622:
9623: @end example
9624:
9625: The first sets all the four default values. The second changes only scale,
9626: to 0.5.
9627:
9628: See also @ref{ticslevel}.
9629:
9630: @node vrange, x2data, view, set-show
9631: @subsection vrange
9632:
9633: @c ?commands set vrange
9634: @c ?commands show vrange
9635: @c ?set vrange
9636: @c ?show vrange
9637: @cindex vrange
9638: @opindex vrange
9639:
9640:
9641: The @ref{urange} and @ref{vrange} commands set the parametric ranges used
9642: to compute x, y, and z values when in `splot` parametric mode. Please see
9643: @ref{xrange} for details.
9644:
9645: @node x2data, x2dtics, vrange, set-show
9646: @subsection x2data
9647:
9648: @c ?commands set x2data
9649: @c ?commands show x2data
9650: @c ?set x2data
9651: @c ?show x2data
9652: @cindex x2data
9653: @opindex x2data
9654:
9655:
9656: The @ref{x2data} command sets data on the x2 (top) axis to timeseries
9657: (dates/times). Please see @ref{xdata}.
9658:
9659: @node x2dtics, x2label, x2data, set-show
9660: @subsection x2dtics
9661:
9662: @c ?commands set x2dtics
9663: @c ?commands set nox2dtics
9664: @c ?commands show x2dtics
9665: @c ?set x2dtics
9666: @c ?set nox2dtics
9667: @c ?show x2dtics
9668: @cindex x2dtics
9669: @opindex x2dtics
9670:
9671:
9672: @cindex nox2dtics
9673:
9674: The @ref{x2dtics} command changes tics on the x2 (top) axis to days of the
9675: week. Please see @ref{xdtics} for details.
9676:
9677: @node x2label, x2mtics, x2dtics, set-show
9678: @subsection x2label
9679:
9680: @c ?commands set x2label
9681: @c ?commands show x2label
9682: @c ?set x2label
9683: @c ?show x2label
9684: @cindex x2label
9685: @opindex x2label
9686:
9687:
9688: The @ref{x2label} command sets the label for the x2 (top) axis. Please see
9689: @ref{xlabel}.
9690:
9691: @node x2mtics, x2range, x2label, set-show
9692: @subsection x2mtics
9693:
9694: @c ?commands set x2mtics
9695: @c ?commands set nox2mtics
9696: @c ?commands show x2mtics
9697: @c ?set x2mtics
9698: @c ?set nox2mtics
9699: @c ?show x2mtics
9700: @cindex x2mtics
9701: @opindex x2mtics
9702:
9703:
9704: @cindex nox2mtics
9705:
9706: The @ref{x2mtics} command changes tics on the x2 (top) axis to months of the
9707: year. Please see @ref{xmtics} for details.
9708:
9709: @node x2range, x2tics, x2mtics, set-show
9710: @subsection x2range
9711:
9712: @c ?commands set x2range
9713: @c ?commands show x2range
9714: @c ?set x2range
9715: @c ?show x2range
9716: @cindex x2range
9717: @opindex x2range
9718:
9719:
9720: The @ref{x2range} command sets the horizontal range that will be displayed on
9721: the x2 (top) axis. Please see @ref{xrange} for details.
9722:
9723: @node x2tics, x2zeroaxis, x2range, set-show
9724: @subsection x2tics
9725:
9726: @c ?commands set x2tics
9727: @c ?commands set nox2tics
9728: @c ?commands show x2tics
9729: @c ?set x2tics
9730: @c ?set nox2tics
9731: @c ?show x2tics
9732: @cindex x2tics
9733: @opindex x2tics
9734:
9735:
9736: @cindex nox2tics
9737:
9738: The @ref{x2tics} command controls major (labelled) tics on the x2 (top) axis.
9739: Please see @ref{xtics} for details.
9740:
9741: @node x2zeroaxis, xdata, x2tics, set-show
9742: @subsection x2zeroaxis
9743:
9744: @c ?commands set x2zeroaxis
9745: @c ?commands set nox2zeroaxis
9746: @c ?commands show x2zeroaxis
9747: @c ?set x2zeroaxis
9748: @c ?set nox2zeroaxis
9749: @c ?show x2zeroaxis
9750: @cindex x2zeroaxis
9751: @opindex x2zeroaxis
9752:
9753:
9754: @cindex nox2zeroaxis
9755:
9756: The @ref{x2zeroaxis} command draws a line at the origin of the x2 (top) axis
9757: (y2 = 0). For details, please see
9758: @ref{zeroaxis}.
9759:
9760: @node xdata, xdtics, x2zeroaxis, set-show
9761: @subsection xdata
9762:
9763: @c ?commands set xdata
9764: @c ?commands show xdata
9765: @c ?set xdata
9766: @c ?show xdata
9767: @cindex xdata
9768: @opindex xdata
9769:
9770:
9771: This command sets the datatype on the x axis to time/date. A similar command
9772: does the same thing for each of the other axes.
9773:
9774: Syntax:
9775: @example
9776: set xdata @{time@}
9777: show xdata
9778:
9779: @end example
9780:
9781: The same syntax applies to @ref{ydata}, @ref{zdata}, @ref{x2data} and @ref{y2data}.
9782:
9783: The `time` option signals that the datatype is indeed time/date. If the
9784: option is not specified, the datatype reverts to normal.
9785:
9786: See @ref{timefmt} to tell `gnuplot` how to read date or time data. The
9787: time/date is converted to seconds from start of the century. There is
9788: currently only one timefmt, which implies that all the time/date columns must
9789: confirm to this format. Specification of ranges should be supplied as quoted
9790: strings according to this format to avoid interpretation of the time/date as
9791: an expression.
9792:
9793: The function 'strftime' (type "man strftime" on unix to look it up) is used
9794: to print tic-mark labels. `gnuplot` tries to figure out a reasonable format
9795: for this unless the `set format x "string"` has supplied something that does
9796: not look like a decimal format (more than one '%' or neither %f nor %g).
9797:
9798: See also `Time/date` for more information.
9799:
9800: @node xdtics, xlabel, xdata, set-show
9801: @subsection xdtics
9802:
9803: @c ?commands set xdtics
9804: @c ?commands set noxdtics
9805: @c ?commands show xdtics
9806: @c ?set xdtics
9807: @c ?set noxdtics
9808: @c ?show xdtics
9809: @cindex xdtics
9810: @opindex xdtics
9811:
9812:
9813: @cindex noxdtics
9814:
9815: The @ref{xdtics} commands converts the x-axis tic marks to days of the week
9816: where 0=Sun and 6=Sat. Overflows are converted modulo 7 to dates. `set
9817: noxdtics` returns the labels to their default values. Similar commands do
9818: the same things for the other axes.
9819:
9820: Syntax:
9821: @example
9822: set xdtics
9823: set noxdtics
9824: show xdtics
9825:
9826: @end example
9827:
9828: The same syntax applies to @ref{ydtics}, @ref{zdtics}, @ref{x2dtics} and @ref{y2dtics}.
9829:
9830: See also the `set format` command.
9831:
9832: @node xlabel, xmtics, xdtics, set-show
9833: @subsection xlabel
9834:
9835: @c ?commands set xlabel
9836: @c ?commands show xlabel
9837: @c ?set xlabel
9838: @c ?show xlabel
9839: @cindex xlabel
9840: @opindex xlabel
9841:
9842:
9843: The @ref{xlabel} command sets the x axis label. Similar commands set labels
9844: on the other axes.
9845:
9846: Syntax:
9847: @example
9848: set xlabel @{"<label>"@} @{<xoff>@}@{,<yoff>@} @{"<font>@{,<size>@}"@}
9849: show xlabel
9850:
9851: @end example
9852:
9853: The same syntax applies to @ref{x2label}, @ref{ylabel}, @ref{y2label} and @ref{zlabel}.
9854:
9855: Specifying the constants <xoff> or <yoff> as optional offsets for a label
9856: will move it <xoff> or <yoff> character widths or heights. For example,
9857: "` set xlabel -1`" will change only the x offset of the xlabel, moving the
9858: label roughly one character width to the left. The size of a character
9859: depends on both the font and the terminal.
9860:
9861: <font> is used to specify the font in which the label is written; the units
9862: of the font <size> depend upon which terminal is used.
9863:
9864: To clear a label, put no options on the command line, e.g., "@ref{y2label}".
9865:
9866: The default positions of the axis labels are as follows:
9867:
9868: xlabel: The x-axis label is centered below the bottom axis.
9869:
9870: ylabel: The position of the y-axis label depends on the terminal, and can be
9871: one of the following three positions:
9872:
9873: 1. Horizontal text flushed left at the top left of the plot. Terminals that
9874: cannot rotate text will probably use this method. If @ref{x2tics} is also
9875: in use, the ylabel may overwrite the left-most x2tic label. This may be
9876: remedied by adjusting the ylabel position or the left margin.
9877:
9878: 2. Vertical text centered vertically at the left of the plot. Terminals
9879: that can rotate text will probably use this method.
9880:
9881: 3. Horizontal text centered vertically at the left of the plot. The EEPIC,
9882: LaTeX and TPIC drivers use this method. The user must insert line breaks
9883: using \\ to prevent the ylabel from overwriting the plot. To produce a
9884: vertical row of characters, add \\ between every printing character (but this
9885: is ugly).
9886:
9887: zlabel: The z-axis label is centered along the z axis and placed in the space
9888: above the grid level.
9889:
9890: y2label: The y2-axis label is placed to the right of the y2 axis. The
9891: position is terminal-dependent in the same manner as is the y-axis label.
9892:
9893: x2label: The x2-axis label is placed above the top axis but below the plot
9894: title. It is also possible to create an x2-axis label by using new-line
9895: characters to make a multi-line plot title, e.g.,
9896:
9897: @example
9898: set title "This is the title\n\nThis is the x2label"
9899:
9900: @end example
9901:
9902: Note that double quotes must be used. The same font will be used for both
9903: lines, of course.
9904:
9905: If you are not satisfied with the default position of an axis label, use @ref{label} instead--that command gives you much more control over where text is
9906: placed.
9907:
9908: Please see `set syntax` for further information about backslash processing
9909: and the difference between single- and double-quoted strings.
9910:
9911: @node xmtics, xrange, xlabel, set-show
9912: @subsection xmtics
9913:
9914: @c ?commands set xmtics
9915: @c ?commands set noxmtics
9916: @c ?commands show xmtics
9917: @c ?set xmtics
9918: @c ?set noxmtics
9919: @c ?show xmtics
9920: @cindex xmtics
9921: @opindex xmtics
9922:
9923:
9924: @cindex noxmtics
9925:
9926: The @ref{xmtics} commands converts the x-axis tic marks to months of the
9927: year where 1=Jan and 12=Dec. Overflows are converted modulo 12 to months.
9928: The tics are returned to their default labels by `set noxmtics`. Similar
9929: commands perform the same duties for the other axes.
9930:
9931: Syntax:
9932: @example
9933: set xmtics
9934: set noxmtics
9935: show xmtics
9936:
9937: @end example
9938:
9939: The same syntax applies to @ref{x2mtics}, @ref{ymtics}, @ref{y2mtics}, and @ref{zmtics}.
9940:
9941: See also the `set format` command.
9942:
9943: @node xrange, xtics, xmtics, set-show
9944: @subsection xrange
9945:
9946: @c ?commands set xrange
9947: @c ?commands show xrange
9948: @c ?set xrange
9949: @c ?show xrange
9950: @cindex xrange
9951: @opindex xrange
9952:
9953:
9954: The @ref{xrange} command sets the horizontal range that will be displayed.
9955: A similar command exists for each of the other axes, as well as for the
9956: polar radius r and the parametric variables t, u, and v.
9957:
9958: Syntax:
9959: @example
9960: set xrange [@{@{<min>@}:@{<max>@}@}] @{@{no@}reverse@} @{@{no@}writeback@}
9961: show xrange
9962:
9963: @end example
9964:
9965: where <min> and <max> terms are constants, expressions or an asterisk to set
9966: autoscaling. If the data are time/date, you must give the range as a quoted
9967: string according to the @ref{timefmt} format. Any value omitted will not be
9968: changed.
9969:
9970: The same syntax applies to @ref{yrange}, @ref{zrange}, @ref{x2range}, @ref{y2range},
9971: @ref{rrange}, @ref{trange}, @ref{urange} and @ref{vrange}.
9972:
9973: The `reverse` option reverses the direction of the axis, e.g., `set xrange
9974: [0:1] reverse` will produce an axis with 1 on the left and 0 on the right.
9975: This is identical to the axis produced by `set xrange [1:0]`, of course.
9976: `reverse` is intended primarily for use with @ref{autoscale}.
9977:
9978: The `writeback` option essentially saves the range found by @ref{autoscale} in
9979: the buffers that would be filled by @ref{xrange}. This is useful if you wish
9980: to plot several functions together but have the range determined by only
9981: some of them. The `writeback` operation is performed during the @ref{plot}
9982: execution, so it must be specified before that command. For example,
9983:
9984: @example
9985: set xrange [-10:10]
9986: set yrange [] writeback
9987: plot sin(x)
9988: set noautoscale y
9989: replot x/2
9990:
9991: @end example
9992:
9993: results in a yrange of [-1:1] as found only from the range of sin(x); the
9994: [-5:5] range of x/2 is ignored. Executing @ref{yrange} after each command
9995: in the above example should help you understand what is going on.
9996:
9997: In 2-d, @ref{xrange} and @ref{yrange} determine the extent of the axes, @ref{trange}
9998: determines the range of the parametric variable in parametric mode or the
9999: range of the angle in polar mode. Similarly in parametric 3-d, @ref{xrange},
10000: @ref{yrange}, and @ref{zrange} govern the axes and @ref{urange} and @ref{vrange} govern the
10001: parametric variables.
10002:
10003: In polar mode, @ref{rrange} determines the radial range plotted. <rmin> acts as
10004: an additive constant to the radius, whereas <rmax> acts as a clip to the
10005: radius---no point with radius greater than <rmax> will be plotted. @ref{xrange}
10006: and @ref{yrange} are affected---the ranges can be set as if the graph was of
10007: r(t)-rmin, with rmin added to all the labels.
10008:
10009: Any range may be partially or totally autoscaled, although it may not make
10010: sense to autoscale a parametric variable unless it is plotted with data.
10011:
10012: Ranges may also be specified on the @ref{plot} command line. A range given on
10013: the plot line will be used for that single @ref{plot} command; a range given by
10014: a `set` command will be used for all subsequent plots that do not specify
10015: their own ranges. The same holds true for `splot`.
10016:
10017: Examples:
10018:
10019: To set the xrange to the default:
10020: @example
10021: set xrange [-10:10]
10022:
10023: @end example
10024:
10025: To set the yrange to increase downwards:
10026: @example
10027: set yrange [10:-10]
10028:
10029: @end example
10030:
10031: To change zmax to 10 without affecting zmin (which may still be autoscaled):
10032: @example
10033: set zrange [:10]
10034:
10035: @end example
10036:
10037: To autoscale xmin while leaving xmax unchanged:
10038: @example
10039: set xrange [*:]
10040:
10041: @end example
10042:
10043: @node xtics, xzeroaxis, xrange, set-show
10044: @subsection xtics
10045:
10046: @c ?commands set xtics
10047: @c ?commands set noxtics
10048: @c ?commands show xtics
10049: @c ?set xtics
10050: @c ?set noxtics
10051: @c ?show xtics
10052: @cindex xtics
10053: @opindex xtics
10054:
10055:
10056: @cindex noxtics
10057:
10058: Fine control of the major (labelled) tics on the x axis is possible with the
10059: @ref{xtics} command. The tics may be turned off with the `set noxtics`
10060: command, and may be turned on (the default state) with @ref{xtics}. Similar
10061: commands control the major tics on the y, z, x2 and y2 axes.
10062:
10063: Syntax:
10064: @example
10065: set xtics @{axis | border@} @{@{no@}mirror@} @{@{no@}rotate@}
10066: @{ autofreq
10067: | <incr>
10068: | <start>, <incr> @{,<end>@}
10069: | (@{"<label>"@} <pos> @{,@{"<label>"@} <pos>@}...) @}
10070: set noxtics
10071: show xtics
10072:
10073: @end example
10074:
10075: The same syntax applies to @ref{ytics}, @ref{ztics}, @ref{x2tics} and @ref{y2tics}.
10076:
10077: `axis` or @ref{border} tells `gnuplot` to put the tics (both the tics themselves
10078: and the accompanying labels) along the axis or the border, respectively. If
10079: the axis is very close to the border, the `axis` option can result in tic
10080: labels overwriting other text written in the margin.
10081:
10082: `mirror` tells `gnuplot` to put unlabelled tics at the same positions on the
10083: opposite border. `nomirror` does what you think it does.
10084:
10085: `rotate` asks `gnuplot` to rotate the text through 90 degrees, which will be
10086: done if the terminal driver in use supports text rotation. `norotate`
10087: cancels this.
10088:
10089: The defaults are `border mirror norotate` for tics on the x and y axes, and
10090: `border nomirror norotate` for tics on the x2 and y2 axes. For the z axis,
10091: the the `@{axis | border@}` option is not available and the default is
10092: `nomirror`. If you do want to mirror the z-axis tics, you might want to
10093: create a bit more room for them with @ref{border}.
10094:
10095: @ref{xtics} with no options restores the default border or axis if xtics are
10096: being displayed; otherwise it has no effect. Any previously specified tic
10097: frequency or position @{and labels@} are retained.
10098:
10099: Positions of the tics are calculated automatically by default or if the
10100: `autofreq` option is given; otherwise they may be specified in either of
10101: two forms:
10102:
10103: The implicit <start>, <incr>, <end> form specifies that a series of tics will
10104: be plotted on the axis between the values <start> and <end> with an increment
10105: of <incr>. If <end> is not given, it is assumed to be infinity. The
10106: increment may be negative. If neither <start> nor <end> is given, <start> is
10107: assumed to be negative infinity, <end> is assumed to be positive infinity,
10108: and the tics will be drawn at integral multiples of <step>. If the axis is
10109: logarithmic, the increment will be used as a multiplicative factor.
10110:
10111: Examples:
10112:
10113: Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
10114: @example
10115: set xtics 0,.5,10
10116:
10117: @end example
10118:
10119: Make tics at ..., -10, -5, 0, 5, 10, ...
10120: @example
10121: set xtics 5
10122:
10123: @end example
10124:
10125: Make tics at 1, 100, 1e4, 1e6, 1e8.
10126: @example
10127: set logscale x; set xtics 1,100,10e8
10128:
10129: @end example
10130:
10131: The explicit ("<label>" <pos>, ...) form allows arbitrary tic positions or
10132: non-numeric tic labels. A set of tics is a set of positions, each with its
10133: own optional label. Note that the label is a string enclosed by quotes. It
10134: may be a constant string, such as "hello", may contain formatting information
10135: for converting the position into its label, such as "%3f clients", or may be
10136: empty, "". See `set format` for more information. If no string is given,
10137: the default label (numerical) is used. In this form, the tics do not need to
10138: be listed in numerical order.
10139:
10140: Examples:
10141: @example
10142: set xtics ("low" 0, "medium" 50, "high" 100)
10143: set xtics (1,2,4,8,16,32,64,128,256,512,1024)
10144: set ytics ("bottom" 0, "" 10, "top" 20)
10145:
10146: @end example
10147:
10148: In the second example, all tics are labelled. In the third, only the end
10149: tics are labelled.
10150:
10151: However they are specified, tics will only be plotted when in range.
10152:
10153: Format (or omission) of the tic labels is controlled by `set format`, unless
10154: the explicit text of a labels is included in the `set xtic (`<label>`)` form.
10155:
10156: Minor (unlabelled) tics can be added by the @ref{mxtics} command.
10157:
10158: In case of timeseries data, position values must be given as quoted dates
10159: or times according to the format @ref{timefmt}. If the <start>, <incr>, <end>
10160: form is used, <start> and <end> must be given according to @ref{timefmt}, but
10161: <incr> must be in seconds. Times will be written out according to the format
10162: given on `set format`, however.
10163:
10164: Examples:
10165: @example
10166: set xdata time
10167: set timefmt "%d/%m"
10168: set format x "%b %d"
10169: set xrange ["01/12":"06/12"]
10170: set xtics "01/12", 172800, "05/12"
10171:
10172: @end example
10173:
10174: @example
10175: set xdata time
10176: set timefmt "%d/%m"
10177: set format x "%b %d"
10178: set xrange ["01/12":"06/12"]
10179: set xtics ("01/12", "" "03/12", "05/12")
10180: @end example
10181:
10182: Both of these will produce tics "Dec 1", "Dec 3", and "Dec 5", but in the
10183: second example the tic at "Dec 3" will be unlabelled.
10184:
10185:
10186: @node xzeroaxis, y2data, xtics, set-show
10187: @subsection xzeroaxis
10188:
10189: @c ?commands set xzeroaxis
10190: @c ?commands set noxzeroaxis
10191: @c ?commands show xzeroaxis
10192: @c ?set xzeroaxis
10193: @c ?set noxzeroaxis
10194: @c ?show xzeroaxis
10195: @cindex xzeroaxis
10196: @opindex xzeroaxis
10197:
10198:
10199: @cindex noxzeroaxis
10200:
10201: The @ref{xzeroaxis} command draws a line at y = 0. For details, please see
10202: @ref{zeroaxis}.
10203:
10204: @node y2data, y2dtics, xzeroaxis, set-show
10205: @subsection y2data
10206:
10207: @c ?commands set y2data
10208: @c ?commands show y2data
10209: @c ?set y2data
10210: @c ?show y2data
10211: @cindex y2data
10212: @opindex y2data
10213:
10214:
10215: The @ref{y2data} command sets y2 (right-hand) axis data to timeseries
10216: (dates/times). Please see @ref{xdata}.
10217:
10218: @node y2dtics, y2label, y2data, set-show
10219: @subsection y2dtics
10220:
10221: @c ?commands set y2dtics
10222: @c ?commands set noy2dtics
10223: @c ?set y2dtics
10224: @c ?set noy2dtics
10225: @c ?show y2dtics
10226: @cindex y2dtics
10227: @opindex y2dtics
10228:
10229:
10230: @cindex noy2dtics
10231:
10232: The @ref{y2dtics} command changes tics on the y2 (right-hand) axis to days of
10233: the week. Please see @ref{xdtics} for details.
10234:
10235: @node y2label, y2mtics, y2dtics, set-show
10236: @subsection y2label
10237:
10238: @c ?commands set y2label
10239: @c ?commands show y2label
10240: @c ?set y2label
10241: @c ?show y2label
10242: @cindex y2label
10243: @opindex y2label
10244:
10245:
10246: The @ref{y2dtics} command sets the label for the y2 (right-hand) axis.
10247: Please see @ref{xlabel}.
10248:
10249: @node y2mtics, y2range, y2label, set-show
10250: @subsection y2mtics
10251:
10252: @c ?commands set y2mtics
10253: @c ?commands set noy2mtics
10254: @c ?commands show y2mtics
10255: @c ?set y2mtics
10256: @c ?set noy2mtics
10257: @c ?show y2mtics
10258: @cindex y2mtics
10259: @opindex y2mtics
10260:
10261:
10262: @cindex noy2mtics
10263:
10264: The @ref{y2mtics} command changes tics on the y2 (right-hand) axis to months
10265: of the year. Please see @ref{xmtics} for details.
10266:
10267: @node y2range, y2tics, y2mtics, set-show
10268: @subsection y2range
10269:
10270: @c ?commands set y2range
10271: @c ?commands show y2range
10272: @c ?set y2range
10273: @c ?show y2range
10274: @cindex y2range
10275: @opindex y2range
10276:
10277:
10278: The @ref{y2range} command sets the vertical range that will be displayed on
10279: the y2 (right-hand) axis. Please see @ref{xrange} for details.
10280:
10281: @node y2tics, y2zeroaxis, y2range, set-show
10282: @subsection y2tics
10283:
10284: @c ?commands set y2tics
10285: @c ?commands set noy2tics
10286: @c ?commands show y2tics
10287: @c ?set y2tics
10288: @c ?set noy2tics
10289: @c ?show y2tics
10290: @cindex y2tics
10291: @opindex y2tics
10292:
10293:
10294: @cindex noy2tics
10295:
10296: The @ref{y2tics} command controls major (labelled) tics on the y2 (right-hand)
10297: axis. Please see @ref{xtics} for details.
10298:
10299: @node y2zeroaxis, ydata, y2tics, set-show
10300: @subsection y2zeroaxis
10301:
10302: @c ?commands set y2zeroaxis
10303: @c ?commands set noy2zeroaxis
10304: @c ?commands show y2zeroaxis
10305: @c ?set y2zeroaxis
10306: @c ?set noy2zeroaxis
10307: @c ?show y2zeroaxis
10308: @cindex y2zeroaxis
10309: @opindex y2zeroaxis
10310:
10311:
10312: @cindex noy2zeroaxis
10313:
10314: The @ref{y2zeroaxis} command draws a line at the origin of the y2 (right-hand)
10315: axis (x2 = 0). For details, please see @ref{zeroaxis}.
10316:
10317: @node ydata, ydtics, y2zeroaxis, set-show
10318: @subsection ydata
10319:
10320: @c ?commands set ydata
10321: @c ?commands show ydata
10322: @c ?set ydata
10323: @c ?show ydata
10324: @cindex ydata
10325: @opindex ydata
10326:
10327:
10328: Sets y-axis data to timeseries (dates/times). Please see @ref{xdata}.
10329:
10330: @node ydtics, ylabel, ydata, set-show
10331: @subsection ydtics
10332:
10333: @c ?commands set ydtics
10334: @c ?commands set noydtics
10335: @c ?commands show ydtics
10336: @c ?set ydtics
10337: @c ?set noydtics
10338: @c ?show ydtics
10339: @cindex ydtics
10340: @opindex ydtics
10341:
10342:
10343: @cindex noydtics
10344:
10345: The @ref{ydtics} command changes tics on the y axis to days of the week.
10346: Please see @ref{xdtics} for details.
10347:
10348: @node ylabel, ymtics, ydtics, set-show
10349: @subsection ylabel
10350:
10351: @c ?commands set ylabel
10352: @c ?commands show ylabel
10353: @c ?set ylabel
10354: @c ?show ylabel
10355: @cindex ylabel
10356: @opindex ylabel
10357:
10358:
10359: This command sets the label for the y axis. Please see @ref{xlabel}.
10360:
10361: @node ymtics, yrange, ylabel, set-show
10362: @subsection ymtics
10363:
10364: @c ?commands set ymtics
10365: @c ?commands set noymtics
10366: @c ?commands show ymtics
10367: @c ?set ymtics
10368: @c ?set noymtics
10369: @c ?show ymtics
10370: @cindex ymtics
10371: @opindex ymtics
10372:
10373:
10374: @cindex noymtics
10375:
10376: The @ref{ymtics} command changes tics on the y axis to months of the year.
10377: Please see @ref{xmtics} for details.
10378:
10379: @node yrange, ytics, ymtics, set-show
10380: @subsection yrange
10381:
10382: @c ?commands set yrange
10383: @c ?commands show yrange
10384: @c ?set yrange
10385: @c ?show yrange
10386: @cindex yrange
10387: @opindex yrange
10388:
10389:
10390: The @ref{yrange} command sets the vertical range that will be displayed on
10391: the y axis. Please see @ref{xrange} for details.
10392:
10393: @node ytics, yzeroaxis, yrange, set-show
10394: @subsection ytics
10395:
10396: @c ?commands set ytics
10397: @c ?commands set noytics
10398: @c ?commands show ytics
10399: @c ?set ytics
10400: @c ?set noytics
10401: @c ?show ytics
10402: @cindex ytics
10403: @opindex ytics
10404:
10405:
10406: @cindex noytics
10407:
10408: The @ref{ytics} command controls major (labelled) tics on the y axis.
10409: Please see @ref{xtics} for details.
10410:
10411: @node yzeroaxis, zdata, ytics, set-show
10412: @subsection yzeroaxis
10413:
10414: @c ?commands set yzeroaxis
10415: @c ?commands set noyzeroaxis
10416: @c ?commands show yzeroaxis
10417: @c ?set yzeroaxis
10418: @c ?set noyzeroaxis
10419: @c ?show yzeroaxis
10420: @cindex yzeroaxis
10421: @opindex yzeroaxis
10422:
10423:
10424: @cindex noyzeroaxis
10425:
10426: The @ref{yzeroaxis} command draws a line at x = 0. For details, please see
10427: @ref{zeroaxis}.
10428:
10429: @node zdata, zdtics, yzeroaxis, set-show
10430: @subsection zdata
10431:
10432: @c ?commands set zdata
10433: @c ?commands show zdata
10434: @c ?set zdata
10435: @c ?show zdata
10436: @cindex zdata
10437: @opindex zdata
10438:
10439:
10440: Set zaxis date to timeseries (dates/times). Please see @ref{xdata}.
10441:
10442: @node zdtics, zero, zdata, set-show
10443: @subsection zdtics
10444:
10445: @c ?commands set zdtics
10446: @c ?commands set nozdtics
10447: @c ?commands show zdtics
10448: @c ?set zdtics
10449: @c ?set nozdtics
10450: @c ?show zdtics
10451: @cindex zdtics
10452: @opindex zdtics
10453:
10454:
10455: @cindex nozdtics
10456:
10457: The @ref{zdtics} command changes tics on the z axis to days of the week.
10458: Please see @ref{xdtics} for details.
10459:
10460: @node zero, zeroaxis, zdtics, set-show
10461: @subsection zero
10462:
10463: @c ?commands set zero
10464: @c ?commands show zero
10465: @c ?set zero
10466: @c ?show zero
10467: @cindex zero
10468: @opindex zero
10469:
10470:
10471: The `zero` value is the default threshold for values approaching 0.0.
10472:
10473: Syntax:
10474: @example
10475: set zero <expression>
10476: show zero
10477:
10478: @end example
10479:
10480: `gnuplot` will not plot a point if its imaginary part is greater in magnitude
10481: than the `zero` threshold. This threshold is also used in various other
10482: parts of `gnuplot` as a (crude) numerical-error threshold. The default
10483: `zero` value is 1e-8. `zero` values larger than 1e-3 (the reciprocal of the
10484: number of pixels in a typical bitmap display) should probably be avoided, but
10485: it is not unreasonable to set `zero` to 0.0.
10486:
10487: @node zeroaxis, zlabel, zero, set-show
10488: @subsection zeroaxis
10489:
10490: @c ?commands set zeroaxis
10491: @c ?commands set nozeroaxis
10492: @c ?commands show zeroaxis
10493: @c ?set zeroaxis
10494: @c ?set nozeroaxis
10495: @c ?show zeroaxis
10496: @cindex zeroaxis
10497: @opindex zeroaxis
10498:
10499:
10500: @cindex nozeroaxis
10501:
10502: The x axis may be drawn by @ref{xzeroaxis} and removed by `set noxzeroaxis`.
10503: Similar commands behave similarly for the y, x2, and y2 axes.
10504:
10505: Syntax:
10506: @example
10507: set @{x|x2|y|y2|@}zeroaxis @{ @{linestyle | ls <line_style>@}
10508: | @{ linetype | lt <line_type>@}
10509: @{ linewidth | lw <line_width>@}@}
10510: set no@{x|x2|y|y2|@}zeroaxis
10511: show @{x|y|@}zeroaxis
10512:
10513: @end example
10514:
10515:
10516: By default, these options are off. The selected zero axis is drawn
10517: with a line of type <line_type> and width <line_width> (if supported
10518: by the terminal driver currently in use), or a user-defined style
10519: <line_style>.
10520:
10521: If no linetype is specified, any zero axes selected will be drawn
10522: using the axis linetype (linetype 0).
10523:
10524: `set zeroaxis l` is equivalent to `set xzeroaxis l; set yzeroaxis l`. `set
10525: nozeroaxis` is equivalent to `set noxzeroaxis; set noyzeroaxis`.
10526:
10527: @node zlabel, zmtics, zeroaxis, set-show
10528: @subsection zlabel
10529:
10530: @c ?commands set zlabel
10531: @c ?commands show zlabel
10532: @c ?set zlabel
10533: @c ?show zlabel
10534: @cindex zlabel
10535: @opindex zlabel
10536:
10537:
10538: This command sets the label for the z axis. Please see @ref{xlabel}.
10539:
10540: @node zmtics, zrange, zlabel, set-show
10541: @subsection zmtics
10542:
10543: @c ?commands set zmtics
10544: @c ?commands set nozmtics
10545: @c ?commands show zmtics
10546: @c ?set zmtics
10547: @c ?set nozmtics
10548: @c ?show zmtics
10549: @cindex zmtics
10550: @opindex zmtics
10551:
10552:
10553: @cindex nozmtics
10554:
10555: The @ref{zmtics} command changes tics on the z axis to months of the year.
10556: Please see @ref{xmtics} for details.
10557:
10558: @node zrange, ztics, zmtics, set-show
10559: @subsection zrange
10560:
10561: @c ?commands set zrange
10562: @c ?commands show zrange
10563: @c ?set zrange
10564: @c ?show zrange
10565: @cindex zrange
10566: @opindex zrange
10567:
10568:
10569: The @ref{zrange} command sets the range that will be displayed on the z axis.
10570: The zrange is used only by `splot` and is ignored by @ref{plot}. Please see @ref{xrange} for details.
10571:
10572: @node ztics, , zrange, set-show
10573: @subsection ztics
10574:
10575: @c ?commands set ztics
10576: @c ?commands set noztics
10577: @c ?commands show ztics
10578: @c ?set ztics
10579: @c ?set noztics
10580: @c ?show ztics
10581: @cindex ztics
10582: @opindex ztics
10583:
10584:
10585: @cindex noztics
10586:
10587: The @ref{ztics} command controls major (labelled) tics on the z axis.
10588: Please see @ref{xtics} for details.
10589:
10590: @node shell, splot, set-show, Commands
10591: @section shell
10592:
10593: @c ?commands shell
10594: @cindex shell
10595: @cmindex shell
10596:
10597:
10598: The @ref{shell} command spawns an interactive shell. To return to `gnuplot`,
10599: type `logout` if using VMS, @ref{exit} or the END-OF-FILE character if using
10600: Unix, `endcli` if using AmigaOS, or @ref{exit} if using MS-DOS or OS/2.
10601:
10602: A single shell command may be spawned by preceding it with the ! character
10603: ($ if using VMS) at the beginning of a command line. Control will return
10604: immediately to `gnuplot` after this command is executed. For example, in
10605: Unix, AmigaOS, MS-DOS or OS/2,
10606:
10607: @example
10608: ! dir
10609:
10610: @end example
10611:
10612: prints a directory listing and then returns to `gnuplot`.
10613:
10614: On an Atari, the `!` command first checks whether a shell is already loaded
10615: and uses it, if available. This is practical if `gnuplot` is run from
10616: `gulam`, for example.
10617:
10618: @node splot, test, shell, Commands
10619: @section splot
10620:
10621: @c ?commands splot
10622: @cindex splot
10623: @cmindex splot
10624:
10625:
10626: `splot` is the command for drawing 3-d plots (well, actually projections on
10627: a 2-d surface, but you knew that). It can create a plot from functions or
10628: a data file in a manner very similar to the @ref{plot} command.
10629:
10630: See @ref{plot} for features common to the @ref{plot} command; only differences are
10631: discussed in detail here. Note specifically that the @ref{binary} and @ref{matrix}
10632: options (discussed under "datafile-modifiers") are not available for @ref{plot}.
10633:
10634: Syntax:
10635: @example
10636: splot @{<ranges>@}
10637: <function> | "<datafile>" @{datafile-modifiers@}@}
10638: @{<title-spec>@} @{with <style>@}
10639: @{, @{definitions,@} <function> ...@}
10640:
10641: @end example
10642:
10643: where either a <function> or the name of a data file enclosed in quotes is
10644: supplied. The function can be a mathematical expression, or a triple of
10645: mathematical expressions in parametric mode.
10646:
10647: By default `splot` draws the xy plane completely below the plotted data.
10648: The offset between the lowest ztic and the xy plane can be changed by @ref{ticslevel}. The orientation of a `splot` projection is controlled by
10649: @ref{view}. See @ref{view} and @ref{ticslevel} for more information.
10650:
10651: The syntax for setting ranges on the `splot` command is the same as for
10652: @ref{plot}. In non-parametric mode, the order in which ranges must be given is
10653: @ref{xrange}, @ref{yrange}, and @ref{zrange}. In parametric mode, the order is @ref{urange},
10654: @ref{vrange}, @ref{xrange}, @ref{yrange}, and @ref{zrange}.
10655:
10656: The `title` option is the same as in @ref{plot}. The operation of @ref{with} is also
10657: the same as in @ref{plot}, except that the plotting styles available to `splot`
10658: are limited to `lines`, `points`, @ref{linespoints}, @ref{dots}, and @ref{impulses}; the
10659: error-bar capabilities of @ref{plot} are not available for `splot`.
10660:
10661: The datafile options have more differences.
10662:
10663: @menu
10664: * data-file_::
10665: * grid_data::
10666: * splot_overview::
10667: @end menu
10668:
10669: @node data-file_, grid_data, splot, splot
10670: @subsection data-file
10671:
10672: @c ?commands splot datafile
10673: @c ?splot datafile
10674: @c ?splot data-file
10675: As for @ref{plot}, discrete data contained in a file can be displayed by
10676: specifying the name of the data file, enclosed in quotes, on the `splot`
10677: command line.
10678:
10679: Syntax:
10680: @example
10681: splot '<file_name>' @{binary | matrix@}
10682: @{index <index list>@}
10683: @{every <every list>@}
10684: @{using <using list>@}
10685:
10686: @end example
10687:
10688: The special filenames `""` and `"-"` are permitted, as in @ref{plot}.
10689:
10690: In brief, @ref{binary} and @ref{matrix} indicate that the the data are in a special
10691: form, @ref{index} selects which data sets in a multi-data-set file are to be
10692: plotted, @ref{every} specifies which datalines (subsets) within a single data
10693: set are to be plotted, and @ref{using} determines how the columns within a single
10694: record are to be interpreted.
10695:
10696: The options @ref{index} and @ref{every} behave the same way as with @ref{plot}; @ref{using}
10697: does so also, except that the @ref{using} list must provide three entries
10698: instead of two.
10699:
10700: The @ref{plot} options @ref{thru} and @ref{smooth} are not available for `splot`, but
10701: `cntrparams` and @ref{dgrid3d} provide limited smoothing cabilities.
10702:
10703: Data file organization is essentially the same as for @ref{plot}, except that
10704: each point is an (x,y,z) triple. If only a single value is provided, it
10705: will be used for z, the datablock number will be used for y, and the index
10706: of the data point in the datablock will be used for x. If two values are
10707: provided, `gnuplot` gives you an error message. Three values are interpreted
10708: as an (x,y,z) triple. Additional values are generally used as errors, which
10709: can be used by `fit`.
10710:
10711: Single blank records separate datablocks in a `splot` datafile; `splot`
10712: treats datablocks as the equivalent of function y-isolines. No line will
10713: join points separated by a blank record. If all datablocks contain the same
10714: number of points, `gnuplot` will draw cross-isolines between datablocks,
10715: connecting corresponding points. This is termed "grid data", and is required
10716: for drawing a surface, for contouring (@ref{contour}) and hidden-line removal
10717: (@ref{hidden3d}). See also `splot grid data`
10718:
10719: It is no longer necessary to specify `parametric` mode for three-column
10720: `splot`s.
10721:
10722: @menu
10723: * binary::
10724: * example_datafile_::
10725: * matrix::
10726: @end menu
10727:
10728: @node binary, example_datafile_, data-file_, data-file_
10729: @subsubsection binary
10730:
10731: @c ?commands splot datafile binary
10732: @c ?splot datafile binary
10733: @c ?splot binary
10734: @c ?data-file binary
10735: @c ?datafile binary
10736: @cindex binary
10737:
10738: @c ?binary data
10739: @c ?binary files
10740: `splot` can read binary files written with a specific format (and on a
10741: system with a compatible binary file representation.)
10742:
10743: In previous versions, `gnuplot` dynamically detected binary data files. It
10744: is now necessary to specify the keyword @ref{binary} directly after the filename.
10745:
10746: Single precision floats are stored in a binary file as follows:
10747:
10748: @example
10749: <N+1> <y0> <y1> <y2> ... <yN>
10750: <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
10751: <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
10752: : : : : ... :
10753:
10754: @end example
10755:
10756: which are converted into triplets:
10757: @example
10758: <x0> <y0> <z0,0>
10759: <x0> <y1> <z0,1>
10760: <x0> <y2> <z0,2>
10761: : : :
10762: <x0> <yN> <z0,N>
10763:
10764: @end example
10765:
10766: @example
10767: <x1> <y0> <z1,0>
10768: <x1> <y1> <z1,1>
10769: : : :
10770:
10771: @end example
10772:
10773: These triplets are then converted into `gnuplot` iso-curves and then
10774: `gnuplot` proceeds in the usual manner to do the rest of the plotting.
10775:
10776: A collection of matrix and vector manipulation routines (in C) is provided
10777: in `binary.c`. The routine to write binary data is
10778:
10779: @example
10780: int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)
10781:
10782: @end example
10783:
10784: An example of using these routines is provided in the file `bf_test.c`, which
10785: generates binary files for the demo file `demo/binary.dem`.
10786:
10787: The @ref{index} keyword is not supported, since the file format allows only one
10788: surface per file. The @ref{every} and @ref{using} filters are supported. @ref{using}
10789: operates as if the data were read in the above triplet form.
10790: @uref{http://www.gnuplot.vt.edu/gnuplot/gpdocs/binary.html,Binary File Splot Demo.}
10791:
10792: @node example_datafile_, matrix, binary, data-file_
10793: @subsubsection example datafile
10794:
10795: @c ?commands splot datafile example
10796: @c ?splot datafile example
10797: @c ?splot example
10798: A simple example of plotting a 3-d data file is
10799:
10800: @example
10801: splot 'datafile.dat'
10802:
10803: @end example
10804:
10805: where the file "datafile.dat" might contain:
10806:
10807: @example
10808: # The valley of the Gnu.
10809: 0 0 10
10810: 0 1 10
10811: 0 2 10
10812:
10813: @end example
10814:
10815: @example
10816: 1 0 10
10817: 1 1 5
10818: 1 2 10
10819:
10820: @end example
10821:
10822: @example
10823: 2 0 10
10824: 2 1 1
10825: 2 2 10
10826:
10827: @end example
10828:
10829: @example
10830: 3 0 10
10831: 3 1 0
10832: 3 2 10
10833:
10834: @end example
10835:
10836: Note that "datafile.dat" defines a 4 by 3 grid ( 4 rows of 3 points each ).
10837: Rows (datablocks) are separated by blank records.
10838:
10839: @c ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/splot.gif" alt="[splot.gif]" width=640 height=480>
10840: Note also that the x value is held constant within each dataline. If you
10841: instead keep y constant, and plot with hidden-line removal enabled, you will
10842: find that the surface is drawn 'inside-out'.
10843:
10844: Actually for grid data it is not necessary to keep the x values constant
10845: within a datablock, nor is it necessary to keep the same sequence of y
10846: values. `gnuplot` requires only that the number of points be the same for
10847: each datablock. However since the surface mesh, from which contours are
10848: derived, connects sequentially corresponding points, the effect of an
10849: irregular grid on a surface plot is unpredictable and should be examined
10850: on a case-by-case basis.
10851:
10852: @node matrix, , example_datafile_, data-file_
10853: @subsubsection matrix
10854:
10855: @c ?commands splot datafile matrix
10856: @c ?splot datafile matrix
10857: @c ?splot matrix
10858: @c ?data-file matrix
10859: @c ?datafile matrix
10860: @cindex matrix
10861:
10862: The @ref{matrix} flag indicates that the ASCII data are stored in matrix format.
10863: The z-values are read in a row at a time, i. e.,
10864: @example
10865: z11 z12 z13 z14 ...
10866: z21 z22 z23 z24 ...
10867: z31 z32 z33 z34 ...
10868: @end example
10869:
10870: and so forth. The row and column indices are used for the x- and y-values.
10871:
10872: @node grid_data, splot_overview, data-file_, splot
10873: @subsection grid_data
10874:
10875: @c ?commands splot grid_data
10876: @c ?splot grid_data
10877: @cindex grid_data
10878:
10879: The 3D routines are designed for points in a grid format, with one sample,
10880: datapoint, at each mesh intersection; the datapoints may originate from
10881: either evaluating a function, see @ref{isosamples}, or reading a datafile,
10882: see `splot datafile`. The term "isoline" is applied to the mesh lines for
10883: both functions and data. Note that the mesh need not be rectangular in x
10884: and y, as it may be parameterized in u and v, see @ref{isosamples}.
10885:
10886: However, `gnuplot` does not require that format. In the case of functions,
10887: 'samples' need not be equal to 'isosamples', i.e., not every x-isoline
10888: sample need intersect a y-isoline. In the case of data files, if there
10889: are an equal number of scattered data points in each datablock, then
10890: "isolines" will connect the points in a datablock, and "cross-isolines"
10891: will connect the corresponding points in each datablock to generate a
10892: "surface". In either case, contour and hidden3d modes may give different
10893: plots than if the points were in the intended format. Scattered data can be
10894: converted to a @{different@} grid format with @ref{dgrid3d}.
10895:
10896: The contour code tests for z intensity along a line between a point on a
10897: y-isoline and the corresponding point in the next y-isoline. Thus a `splot`
10898: contour of a surface with samples on the x-isolines that do not coincide with
10899: a y-isoline intersection will ignore such samples. Try:
10900: @example
10901: set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
10902: set function style lp
10903: set contour
10904: set isosamples 10,10; set samples 10,10;
10905: splot cos(x)*cos(y)
10906: set samples 4,10; replot
10907: set samples 10,4; replot
10908:
10909: @end example
10910:
10911:
10912: @node splot_overview, , grid_data, splot
10913: @subsection splot_overview
10914:
10915: @c ?commands splot_overview
10916: @c ? splot_overview
10917: `splot` can display a surface as a collection of points, or by connecting
10918: those points. As with @ref{plot}, the points may be read from a data file or
10919: result from evaluation of a function at specified intervals, see @ref{isosamples}. The surface may be approximated by connecting the points
10920: with straight line segments, see @ref{surface}, in which case the surface
10921: can be made opaque with `set hidden3d.` The orientation from which the 3d
10922: surface is viewed can be changed with @ref{view}.
10923:
10924: Additionally, for points in a grid format, `splot` can interpolate points
10925: having a common amplitude (see @ref{contour}) and can then connect those
10926: new points to display contour lines, either directly with straight-line
10927: segments or smoothed lines (see `set cntrparams`). Functions are already
10928: evaluated in a grid format, determined by @ref{isosamples} and @ref{samples},
10929: while file data must either be in a grid format, as described in `data-file`,
10930: or be used to generate a grid (see @ref{dgrid3d}).
10931:
10932: Contour lines may be displayed either on the surface or projected onto the
10933: base. The base projections of the contour lines may be written to a
10934: file, and then read with @ref{plot}, to take advantage of @ref{plot}'s additional
10935: formatting capabilities.
10936:
10937: @node test, update, splot, Commands
10938: @section test
10939:
10940: @c ?commands test
10941: @cindex test
10942: @cmindex test
10943:
10944:
10945: @ref{test} creates a display of line and point styles and other useful things
10946: appropriate for the terminal you are using.
10947:
10948: Syntax:
10949: @example
10950: test
10951:
10952: @end example
10953:
10954: @node update, , test, Commands
10955: @section update
10956:
10957: @c ?commands update
10958: @cindex update
10959: @cmindex update
10960:
10961:
10962: This command writes the current values of the fit parameters into the given
10963: file, formatted as an initial-value file (as described in the `fit`section).
10964: This is useful for saving the current values for later use or for restarting
10965: a converged or stopped fit.
10966:
10967: Syntax:
10968: @example
10969: update <filename> @{<filename>@}
10970:
10971: @end example
10972:
10973: If a second filename is supplied, the updated values are written to this
10974: file, and the original parameter file is left unmodified.
10975:
10976: Otherwise, if the file already exists, `gnuplot` first renames it by
10977: appending `.old` and then opens a new file. That is, "`update 'fred'`"
10978: behaves the same as "`!rename fred fred.old; update 'fred.old' 'fred'`".
10979: [On DOS and other systems that use the twelve-character "filename.ext"
10980: naming convention, "ext" will be "`old`" and "filename" will be related
10981: (hopefully recognizably) to the initial name. Renaming is not done at all
10982: on VMS systems, since they use file-versioning.]
10983:
10984: Please see `fit` for more information.
10985:
10986: @node Graphical_User_Interfaces, Bugs, Commands, Top
10987: @chapter Graphical User Interfaces
10988:
10989: @c ?graphical user interfaces
10990: @cindex gui's
10991:
10992: Several graphical user interfaces have been written for `gnuplot` and one for
10993: win32 is included in this distribution. In addition, there is a Macintosh
10994: interface at
10995: @uref{ftp://ftp.ee.gatech.edu/pub/mac/gnuplot,ftp://ftp.ee.gatech.edu/pub/mac/gnuplot
10996: }
10997: and several X11 interfaces include three Tcl/Tk located at the usual Tcl/Tk
10998: repositories.
10999:
11000: @node Bugs, Concept_Index, Graphical_User_Interfaces, Top
11001: @chapter Bugs
11002:
11003: @cindex bugs
11004:
11005: Floating point exceptions (floating point number too large/small, divide by
11006: zero, etc.) may occasionally be generated by user defined functions. Some of
11007: the demos in particular may cause numbers to exceed the floating point range.
11008: Whether the system ignores such exceptions (in which case `gnuplot` labels
11009: the corresponding point as undefined) or aborts `gnuplot` depends on the
11010: compiler/runtime environment.
11011:
11012: The bessel functions do not work for complex arguments.
11013:
11014: The gamma function does not work for complex arguments.
11015:
11016: As of `gnuplot` version 3.7, all development has been done using ANSI C.
11017: With current operating system, compiler, and library releases, the OS
11018: specific bugs documented in release 3.5, now relegated to `old_bugs`, may
11019: no longer be relevant.
11020:
11021: Bugs reported since the current release may be located via the official
11022: distribution site:
11023: @example
11024: ftp://ftp.dartmouth.edu/pub/gnuplot
11025: http://www.cs.dartmouth.edu/gnuplot_info.html
11026:
11027: @end example
11028:
11029: Please e-mail any bugs to bug-gnuplot@@dartmouth.edu.
11030:
11031: @menu
11032: * Old_bugs::
11033: @end menu
11034:
11035: @node Old_bugs, , Bugs, Bugs
11036: @section Old_bugs
11037:
11038: @cindex old_bugs
11039:
11040: @cindex os_bugs
11041:
11042: There is a bug in the stdio library for old Sun operating systems (SunOS
11043: Sys4-3.2). The "%g" format for 'printf' sometimes incorrectly prints numbers
11044: (e.g., 200000.0 as "2"). Thus, tic mark labels may be incorrect on a Sun4
11045: version of `gnuplot`. A work-around is to rescale the data or use the `set
11046: format` command to change the tic mark format to "%7.0f" or some other
11047: appropriate format. This appears to have been fixed in SunOS 4.0.
11048:
11049: Another bug: On a Sun3 under SunOS 4.0, and on Sun4's under Sys4-3.2 and
11050: SunOS 4.0, the 'sscanf' routine incorrectly parses "00 12" with the format
11051: "%f %f" and reads 0 and 0 instead of 0 and 12. This affects data input. If
11052: the data file contains x coordinates that are zero but are specified like
11053: '00', '000', etc, then you will read the wrong y values. Check any data
11054: files or upgrade the SunOS. It appears to have been fixed in SunOS 4.1.1.
11055:
11056: Suns appear to overflow when calculating exp(-x) for large x, so `gnuplot`
11057: gets an undefined result. One work-around is to make a user-defined function
11058: like e(x) = x<-500 ? 0 : exp(x). This affects plots of Gaussians (exp(-x*x))
11059: in particular, since x*x grows quite rapidly.
11060:
11061: Microsoft C 5.1 has a nasty bug associated with the %g format for 'printf'.
11062: When any of the formats "%.2g", "%.1g", "%.0g", "%.g" are used, 'printf' will
11063: incorrectly print numbers in the range 1e-4 to 1e-1. Numbers that should be
11064: printed in the %e format are incorrectly printed in the %f format, with the
11065: wrong number of zeros after the decimal point. To work around this problem,
11066: use the %e or %f formats explicitly.
11067:
11068: `gnuplot`, when compiled with Microsoft C, did not work correctly on two VGA
11069: displays that were tested. The CGA, EGA and VGA drivers should probably be
11070: rewritten to use the Microsoft C graphics library. `gnuplot` compiled with
11071: Borland C++ uses the Turbo C graphics drivers and does work correctly with
11072: VGA displays.
11073:
11074: VAX/VMS 4.7 C compiler release 2.4 also has a poorly implemented %g format
11075: for 'printf'. The numbers are printed numerically correct, but may not be in
11076: the requested format. The K&R second edition says that for the %g format, %e
11077: is used if the exponent is less than -4 or greater than or equal to the
11078: precision. The VAX uses %e format if the exponent is less than -1. The VAX
11079: appears to take no notice of the precision when deciding whether to use %e or
11080: %f for numbers less than 1. To work around this problem, use the %e or %f
11081: formats explicitly. From the VAX C 2.4 release notes: e,E,f,F,g,G Result
11082: will always contain a decimal point. For g and G, trailing zeros will not
11083: be removed from the result.
11084:
11085: VAX/VMS 5.2 C compiler release 3.0 has a slightly better implemented %g
11086: format than release 2.4, but not much. Trailing decimal points are now
11087: removed, but trailing zeros are still not removed from %g numbers in
11088: exponential format.
11089:
11090: The two preceding problems are actually in the libraries rather than in the
11091: compilers. Thus the problems will occur whether `gnuplot` is built using
11092: either the DEC compiler or some other one (e.g. the latest gcc).
11093:
11094: ULTRIX X11R3 has a bug that causes the X11 driver to display "every other"
11095: graph. The bug seems to be fixed in DEC's release of X11R4 so newer releases
11096: of ULTRIX don't seem to have the problem. Solutions for older sites include
11097: upgrading the X11 libraries (from DEC or direct from MIT) or defining
11098: ULTRIX_KLUDGE when compiling the x11.trm file. Note that the kludge is not
11099: an ideal fix, however.
11100:
11101: The constant HUGE was incorrectly defined in the NeXT OS 2.0 operating
11102: system. HUGE should be set to 1e38 in plot.h. This error has been corrected
11103: in the 2.1 version of NeXT OS.
11104:
11105: Some older models of HP plotters do not have a page eject command 'PG'. The
11106: current HPGL driver uses this command in HPGL_reset. This may need to be
11107: removed for these plotters. The current PCL5 driver uses HPGL/2 for text as
11108: well as graphics. This should be modified to use scalable PCL fonts.
11109:
11110: On the Atari version, it is not possible to send output directly to the
11111: printer (using `/dev/lp` as output file), since CRs are added to LFs in
11112: binary output. As a work-around, write the output to a file and copy it to
11113: the printer afterwards using a shell command.
11114:
11115: On AIX 4, the literal 'NaNq' in a datafile causes the special internal value
11116: 'not-a-number' to be stored, rather than setting an internal 'undefined'
11117: flag. A workaround is to use `set missing 'NaNq'`.
11118:
11119: There may be an up-to-date list of bugs since the release on the WWW page:
11120: @example
11121: http://www.cs.dartmouth.edu/gnuplot_info.html
11122:
11123: @end example
11124:
11125: Please report any bugs to bug-gnuplot@@dartmouth.edu.
11126: @node Concept_Index, Command_Index, Bugs, Top
11127: @unnumbered Concept Index
11128: @printindex cp
11129:
11130: @node Command_Index, Options_Index, Concept_Index, Top
11131: @unnumbered Command Index
11132: @printindex cm
11133:
11134: @node Options_Index, Function_Index, Command_Index, Top
11135: @unnumbered Options Index
11136: @printindex op
11137:
11138: @node Function_Index, Terminal_Index, Options_Index, Top
11139: @unnumbered Function Index
11140: @printindex fn
11141:
11142: @node Terminal_Index, , Function_Index, Top
11143: @unnumbered Terminal Index
11144: @printindex tm
11145:
11146: @c @shortcontents
11147: @contents
11148: @bye
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