Annotation of OpenXM_contrib/gnuplot/docs/gnuplot.doc, Revision 1.1.1.2
1.1.1.2 ! maekawa 1: C RCS $Id: gnuplot.doc,v 1.20.2.3 1999/10/27 10:10:16 lhecking Exp $
1.1 maekawa 2: C 3 December 1998
3: C Copyright (C) 1986 - 1993, 1998 Thomas Williams, Colin Kelley
4: C
5: ^ <h2> An Interactive Plotting Program </h2><p>
6: ^ <h2> Thomas Williams & Colin Kelley</h2><p>
7: ^ <h2> Version 3.7 organized by: David Denholm </h2><p>
8: ^ <h2>Major contributors (alphabetic order):</h2>
9: ^<ul><h3>
10: ^<li> Hans-Bernhard Broeker
11: ^<li> John Campbell
12: ^<li> Robert Cunningham
13: ^<li> David Denholm
14: ^<li> Gershon Elber
15: ^<li> Roger Fearick
16: ^<li> Carsten Grammes
17: ^<li> Lucas Hart
18: ^<li> Lars Hecking
19: ^<li> Thomas Koenig
20: ^<li> David Kotz
21: ^<li> Ed Kubaitis
22: ^<li> Russell Lang
23: ^<li> Alexander Lehmann
24: ^<li> Alexander Mai
25: ^<li> Carsten Steger
26: ^<li> Tom Tkacik
27: ^<li> Jos Van der Woude
28: ^<li> James R. Van Zandt
29: ^<li> Alex Woo
30: ^</h3></ul> <p>
31: ^<h2> Copyright (C) 1986 - 1993, 1998 Thomas Williams, Colin Kelley<p>
32: ^ Mailing list for comments: info-gnuplot@dartmouth.edu <p>
33: ^ Mailing list for bug reports: bug-gnuplot@dartmouth.edu<p>
34: ^</h2><p>
35: ^<h3> This manual was prepared by Dick Crawford</h3><p>
36: ^<h3> 3 December 1998</h3><p>
37: ^<hr>
38: 1 gnuplot
39: 2 Copyright
40: ?copyright
41: ?license
42: Copyright (C) 1986 - 1993, 1998 Thomas Williams, Colin Kelley
43:
44: Permission to use, copy, and distribute this software and its
45: documentation for any purpose with or without fee is hereby granted,
46: provided that the above copyright notice appear in all copies and
47: that both that copyright notice and this permission notice appear
48: in supporting documentation.
49:
50: Permission to modify the software is granted, but not the right to
51: distribute the complete modified source code. Modifications are to
52: be distributed as patches to the released version. Permission to
53: distribute binaries produced by compiling modified sources is granted,
54: provided you
55: 1. distribute the corresponding source modifications from the
56: released version in the form of a patch file along with the binaries,
57: 2. add special version identification to distinguish your version
58: in addition to the base release version number,
59: 3. provide your name and address as the primary contact for the
60: support of your modified version, and
61: 4. retain our contact information in regard to use of the base
62: software.
63: Permission to distribute the released version of the source code along
64: with corresponding source modifications in the form of a patch file is
65: granted with same provisions 2 through 4 for binary distributions.
66:
67: This software is provided "as is" without express or implied warranty
68: to the extent permitted by applicable law.
69:
70:
71: AUTHORS
72:
73: Original Software:
74: Thomas Williams, Colin Kelley.
75:
76: Gnuplot 2.0 additions:
77: Russell Lang, Dave Kotz, John Campbell.
78:
79: Gnuplot 3.0 additions:
80: Gershon Elber and many others.
81: 2 Introduction
82: ?introduction
83: ?
84: `gnuplot` is a command-driven interactive function and data plotting program.
85: It is case sensitive (commands and function names written in lowercase are
86: not the same as those written in CAPS). All command names may be abbreviated
87: as long as the abbreviation is not ambiguous. Any number of commands may
88: appear on a line (with the exception that `load` or `call` must be the final
89: command), separated by semicolons (;). Strings are indicated with quotes.
90: They may be either single or double quotation marks, e.g.,
91:
92: load "filename"
93: cd 'dir'
94:
95: although there are some subtle differences (see `syntax` for more details).
96:
97: Any command-line arguments are assumed to be names of files containing
98: `gnuplot` commands, with the exception of standard X11 arguments, which are
99: processed first. Each file is loaded with the `load` command, in the order
100: specified. `gnuplot` exits after the last file is processed. When no load
101: files are named, `gnuplot` enters into an interactive mode. The special
102: filename "-" is used to denote standard input. See "help batch/interactive"
103: for more details.
104:
105: Many `gnuplot` commands have multiple options. These options must appear in
106: the proper order, although unwanted ones may be omitted in most cases. Thus
107: if the entire command is "command a b c", then "command a c" will probably
108: work, but "command c a" will fail.
109:
110: Commands may extend over several input lines by ending each line but the last
111: with a backslash (\). The backslash must be the _last_ character on each
112: line. The effect is as if the backslash and newline were not there. That
113: is, no white space is implied, nor is a comment terminated. Therefore,
114: commenting out a continued line comments out the entire command (see
115: `comment`). But note that if an error occurs somewhere on a multi-line
116: command, the parser may not be able to locate precisely where the error is
117: and in that case will not necessarily point to the correct line.
118:
119: In this document, curly braces ({}) denote optional arguments and a vertical
120: bar (|) separates mutually exclusive choices. `gnuplot` keywords or `help`
121: topics are indicated by backquotes or `boldface` (where available). Angle
122: brackets (<>) are used to mark replaceable tokens. In many cases, a default
123: value of the token will be taken for optional arguments if the token is
124: omitted, but these cases are not always denoted with braces around the angle
125: brackets.
126:
127: For on-line help on any topic, type `help` followed by the name of the topic
128: or just `help` or `?` to get a menu of available topics.
129:
130: The new `gnuplot` user should begin by reading about `plotting` (if on-line,
131: type `help plotting`).
1.1.1.2 ! maekawa 132: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/simple.html"> Simple Plots Demo </a>
1.1 maekawa 133: 2 Seeking-assistance
134: ?seeking-assistance
135: There is a mailing list for `gnuplot` users. Note, however, that the
136: newsgroup
137: comp.graphics.apps.gnuplot
138: is identical to the mailing list (they both carry the same set of messages).
139: We prefer that you read the messages through the newsgroup rather than
140: subscribing to the mailing list. Administrative requests should be sent to
141: majordomo@dartmouth.edu
142: Send a message with the body (not the subject) consisting of the single word
143: "help" (without the quotes) for more details.
144:
145: The address for mailing to list members is:
146: info-gnuplot@dartmouth.edu
147:
148: Bug reports and code contributions should be mailed to:
149: bug-gnuplot@dartmouth.edu
150:
151: The list of those interested in beta-test versions is:
152: info-gnuplot-beta@dartmouth.edu
153:
154: There is also a World Wide Web page with up-to-date information, including
155: known bugs:
156: ^ <a href="http://www.cs.dartmouth.edu/gnuplot_info.html">
157: http://www.cs.dartmouth.edu/gnuplot_info.html
158: ^ </a>
159:
160: Before seeking help, please check the
1.1.1.2 ! maekawa 161: ^ <a href="http://www.ucc.ie/gnuplot/gnuplot-faq.html">
1.1 maekawa 162: FAQ (Frequently Asked Questions) list.
163: ^ </a>
164: If you do not have a copy of the FAQ, you may request a copy by email from
165: the Majordomo address above, ftp a copy from
1.1.1.2 ! maekawa 166: ftp://ftp.ucc.ie/pub/gnuplot/faq,
! 167: ftp://ftp.gnuplot.vt.edu/pub/gnuplot/faq,
1.1 maekawa 168: or see the WWW `gnuplot` page.
169:
170: When posting a question, please include full details of the version of
171: `gnuplot`, the machine, and operating system you are using. A _small_ script
172: demonstrating the problem may be useful. Function plots are preferable to
173: datafile plots. If email-ing to info-gnuplot, please state whether or not
174: you are subscribed to the list, so that users who use news will know to email
175: a reply to you. There is a form for such postings on the WWW site.
176: 2 What's New in version 3.7
177: ?new-features
178: Gnuplot version 3.7 contains many new features. This section gives a partial
179: list and links to the new items in no particular order.
180:
181: 1. `fit f(x) 'file' via` uses the Marquardt-Levenberg method to fit data.
182: (This is only slightly different from the `gnufit` patch available for 3.5.)
183:
184: 2. Greatly expanded `using` command. See `plot using`.
185:
186: 3. `set timefmt` allows for the use of dates as input and output for time
187: series plots. See `Time/Date data` and
1.1.1.2 ! maekawa 188: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/timedat.html">
1.1 maekawa 189: timedat.dem.
190: ^ </a>
191:
192: 4. Multiline labels and font selection in some drivers.
193:
194: 5. Minor (unlabeled) tics. See `set mxtics`.
195:
196: 6. `key` options for moving the key box in the page (and even outside of the
197: plot), putting a title on it and a box around it, and more. See `set key`.
198:
199: 7. Multiplots on a single logical page with `set multiplot`.
200:
201: 8. Enhanced `postscript` driver with super/subscripts and font changes.
202: (This was a separate driver (`enhpost`) that was available as a patch for
203: 3.5.)
204:
205: 9. Second axes: use the top and right axes independently of the bottom and
206: left, both for plotting and labels. See `plot`.
207:
208: 10. Special datafile names `'-'` and `""`. See `plot special-filenames`.
209:
210: 11. Additional coordinate systems for labels and arrows. See `coordinates`.
211:
212: 12. `set size` can try to plot with a specified aspect ratio.
213:
214: 13. `set missing` now treats missing data correctly.
215:
216: 14. The `call` command: `load` with arguments.
217:
218: 15. More flexible `range` commands with `reverse` and `writeback` keywords.
219:
220: 16. `set encoding` for multi-lingual encoding.
221:
222: 17. New `x11` driver with persistent and multiple windows.
223:
224: 18. New plotting styles: `xerrorbars`, `histeps`, `financebars` and more.
225: See `set style`.
226:
227: 19. New tic label formats, including `"%l %L"` which uses the mantissa and
228: exponents to a given base for labels. See `set format`.
229:
230: 20. New drivers, including `cgm` for inclusion into MS-Office applications
231: and `gif` for serving plots to the WEB.
232:
233: 21. Smoothing and spline-fitting options for `plot`. See `plot smooth`.
234:
235: 22. `set margin` and `set origin` give much better control over where a
236: graph appears on the page.
237:
238: 23. `set border` now controls each border individually.
239:
240: 24. The new commands `if` and `reread` allow command loops.
241:
242: 25. Point styles and sizes, line types and widths can be specified on the
243: `plot` command. Line types and widths can also be specified for grids,
244: borders, tics and arrows. See `plot with`. Furthermore these types may be
245: combined and stored for further use. See `set linestyle`.
246:
247: 26. Text (labels, tic labels, and the time stamp) can be written vertically
248: by those terminals capable of doing so.
249: 2 Batch/Interactive Operation
250: ?batch/interactive
251: `gnuplot` may be executed in either batch or interactive modes, and the two
252: may even be mixed together on many systems.
253:
254: Any command-line arguments are assumed to be names of files containing
255: `gnuplot` commands (with the exception of standard X11 arguments, which are
256: processed first). Each file is loaded with the `load` command, in the order
257: specified. `gnuplot` exits after the last file is processed. When no load
258: files are named, `gnuplot` enters into an interactive mode. The special
259: filename "-" is used to denote standard input.
260:
261: Both the `exit` and `quit` commands terminate the current command file and
262: `load` the next one, until all have been processed.
263:
264: Examples:
265:
266: To launch an interactive session:
267: gnuplot
268:
269: To launch a batch session using two command files "input1" and "input2":
270: gnuplot input1 input2
271:
272: To launch an interactive session after an initialization file "header" and
273: followed by another command file "trailer":
274: gnuplot header - trailer
275: 2 Command-line-editing
276: ?line-editing
277: ?editing
278: ?history
279: ?command-line-editing
280: Command-line editing is supported by the Unix, Atari, VMS, MS-DOS and OS/2
281: versions of `gnuplot`. Also, a history mechanism allows previous commands to
282: be edited and re-executed. After the command line has been edited, a newline
283: or carriage return will enter the entire line without regard to where the
284: cursor is positioned.
285:
286: (The readline function in `gnuplot` is not the same as the readline used in
287: GNU Bash and GNU Emacs. If the GNU version is desired, it may be selected
288: instead of the `gnuplot` version at compile time.)
289:
290:
291: The editing commands are as follows:
292:
293: @start table - first is interactive cleartext form
294: `Line-editing`:
295:
296: ^B moves back a single character.
297: ^F moves forward a single character.
298: ^A moves to the beginning of the line.
299: ^E moves to the end of the line.
300: ^H and DEL delete the previous character.
301: ^D deletes the current character.
302: ^K deletes from current position to the end of line.
303: ^L,^R redraws line in case it gets trashed.
304: ^U deletes the entire line.
305: ^W deletes the last word.
306:
307: `History`:
308:
309: ^P moves back through history.
310: ^N moves forward through history.
311: #\begin{tabular}{|cl|} \hline
312: #\multicolumn{2}{|c|}{Command-line Editing Commands} \\ \hline \hline
313: #Character & Function \\ \hline
314: # & \multicolumn{1}{|c|}{Line Editing}\\ \cline{2-2}
315: #\verb~^B~ & move back a single character.\\
316: #\verb~^F~ & move forward a single character.\\
317: #\verb~^A~ & move to the beginning of the line.\\
318: #\verb~^E~ & move to the end of the line.\\
319: #\verb~^H, DEL~ & delete the previous character.\\
320: #\verb~^D~ & delete the current character.\\
321: #\verb~^K~ & delete from current position to the end of line.\\
322: #\verb~^L, ^R~ & redraw line in case it gets trashed.\\
323: #\verb~^U~ & delete the entire line. \\
324: #\verb~^W~ & delete from the current word to the end of line. \\ \hline
325: # & \multicolumn{1}{|c|}{History} \\ \cline{2-2}
326: #\verb~^P~ & move back through history.\\
327: #\verb~^N~ & move forward through history.\\
328: %c l .
329: %Character@Function
330: %_
331: %@Line Editing
332: %^B@move back a single character.
333: %^F@move forward a single character.
334: %^A@move to the beginning of the line.
335: %^E@move to the end of the line.
336: %^H, DEL@delete the previous character.
337: %^D@delete the current character.
338: %^K@delete from current position to the end of line.
339: %^L, ^R@redraw line in case it gets trashed.
340: %^U@delete the entire line.
341: %^W@delete from the current word to the end of line.
342: %_
343: %@History
344: %^P@move back through history.
345: %^N@move forward through history.
346: @end table
347:
348: On the IBM PC, the use of a TSR program such as DOSEDIT or CED may be desired
349: for line editing. The default makefile assumes that this is the case; by
350: default `gnuplot` will be compiled with no line-editing capability. If you
351: want to use `gnuplot`'s line editing, set READLINE in the makefile and add
352: readline.obj to the link file. The following arrow keys may be used on the
353: IBM PC and Atari versions if readline is used:
354:
355: @start table - first is interactive cleartext form
356: Left Arrow - same as ^B.
357: Right Arrow - same as ^F.
358: Ctrl Left Arrow - same as ^A.
359: Ctrl Right Arrow - same as ^E.
360: Up Arrow - same as ^P.
361: Down Arrow - same as ^N.
362: #\begin{tabular}{|cl|} \hline
363: #Arrow key & Function \\ \hline
364: #Left & same as \verb~^B~. \\
365: #Right & same as \verb~^F~. \\
366: #Ctrl Left & same as \verb~^A~. \\
367: #Ctrl Right & same as \verb~^E~. \\
368: #Up & same as \verb~^P~. \\
369: #Down & same as \verb~^N~. \\
370: %c l .
371: %Arrow key@Function
372: %_
373: %Left Arrow@same as ^B.
374: %Right Arrow@same as ^F.
375: %Ctrl Left Arrow@same as ^A.
376: %Ctrl Right Arrow@same as ^E.
377: %Up Arrow@same as ^P.
378: %Down Arrow@same as ^N.
379: %_
380: @end table
381:
382: The Atari version of readline defines some additional key aliases:
383:
384: @start table - first is interactive cleartext form
385: Undo - same as ^L.
386: Home - same as ^A.
387: Ctrl Home - same as ^E.
388: Esc - same as ^U.
389: Help - `help` plus return.
390: Ctrl Help - `help `.
391: #\begin{tabular}{|cl|} \hline
392: #Arrow key & Function \\ \hline
393: #Undo & same as \verb~^L~. \\
394: #Home & same as \verb~^A~. \\
395: #Ctrl Home & same as \verb~^E~. \\
396: #Esc & same as \verb~^U~. \\
397: #Help & `{\bf help}' plus return. \\
398: #Ctrl Help & `{\bf help }'. \\
399: %c l .
400: %Arrow key@Function
401: %_
402: %Undo@same as ^L.
403: %Home@same as ^A.
404: %Ctrl Home@same as ^E.
405: %Esc@same as ^U.
406: %Help@help plus return.
407: %Ctrl Help@help .
408: %_
409: @end table
410: 2 Comments
411: ?comments
412: Comments are supported as follows: a `#` may appear in most places in a line
413: and `gnuplot` will ignore the rest of the line. It will not have this effect
414: inside quotes, inside numbers (including complex numbers), inside command
415: substitutions, etc. In short, it works anywhere it makes sense to work.
416: 2 Coordinates
417: ?coordinates
418: The commands `set arrow`, `set key`, and `set label` allow you to draw
419: something at an arbitrary position on the graph. This position is specified
420: by the syntax:
421:
422: {<system>} <x>, {<system>} <y> {,{<system>} <z>}
423:
424: Each <system> can either be `first`, `second`, `graph` or `screen`.
425:
426: `first` places the x, y, or z coordinate in the system defined by the left
427: and bottom axes; `second` places it in the system defined by the second axes
428: (top and right); `graph` specifies the area within the axes---0,0 is bottom
429: left and 1,1 is top right (for splot, 0,0,0 is bottom left of plotting area;
430: use negative z to get to the base---see `set ticslevel`); and `screen`
431: specifies the screen area (the entire area---not just the portion selected by
432: `set size`), with 0,0 at bottom left and 1,1 at top right.
433:
434: If the coordinate system for x is not specified, `first` is used. If the
435: system for y is not specified, the one used for x is adopted.
436:
437: If one (or more) axis is timeseries, the appropriate coordinate should
438: be given as a quoted time string according to the `timefmt` format string.
439: See `set xdata` and `set timefmt`. `gnuplot` will also accept an integer
440: expression, which will be interpreted as seconds from 1 January 2000.
441: 2 Environment
442: ?environment
443: A number of shell environment variables are understood by `gnuplot`. None of
444: these are required, but may be useful.
445:
446: If GNUTERM is defined, it is used as the name of the terminal type to be
447: used. This overrides any terminal type sensed by `gnuplot` on start-up, but
448: is itself overridden by the .gnuplot (or equivalent) start-up file (see
449: `start-up`) and, of course, by later explicit changes.
450:
451: On Unix, AmigaOS, AtariTOS, MS-DOS and OS/2, GNUHELP may be defined to be the
452: pathname of the HELP file (gnuplot.gih).
453:
454: On VMS, the logical name GNUPLOT$HELP should be defined as the name of the
455: help library for `gnuplot`. The `gnuplot` help can be put inside any system
456: help library, allowing access to help from both within and outside `gnuplot`
457: if desired.
458:
459: On Unix, HOME is used as the name of a directory to search for a .gnuplot
460: file if none is found in the current directory. On AmigaOS, AtariTOS,
461: MS-DOS and OS/2, gnuplot is used. On VMS, SYS$LOGIN: is used. See `help
462: start-up`.
463:
464: On Unix, PAGER is used as an output filter for help messages.
465:
466: On Unix, AtariTOS and AmigaOS, SHELL is used for the `shell` command. On
467: MS-DOS and OS/2, COMSPEC is used for the `shell` command.
468:
469: On MS-DOS, if the BGI or Watcom interface is used, PCTRM is used to tell
470: the maximum resolution supported by your monitor by setting it to
471: S<max. horizontal resolution>. E.g. if your monitor's maximum resolution is
472: 800x600, then use:
473: set PCTRM=S800
474: If PCTRM is not set, standard VGA is used.
475:
476: FIT_SCRIPT may be used to specify a `gnuplot` command to be executed when a
477: fit is interrupted---see `fit`. FIT_LOG specifies the filename of the
478: logfile maintained by fit.
479: 2 Expressions
480: ?expressions
481: In general, any mathematical expression accepted by C, FORTRAN, Pascal, or
482: BASIC is valid. The precedence of these operators is determined by the
483: specifications of the C programming language. White space (spaces and tabs)
484: is ignored inside expressions.
485:
486: Complex constants are expressed as {<real>,<imag>}, where <real> and <imag>
487: must be numerical constants. For example, {3,2} represents 3 + 2i; {0,1}
488: represents 'i' itself. The curly braces are explicitly required here.
489:
490: Note that gnuplot uses both "real" and "integer" arithmetic, like FORTRAN and
491: C. Integers are entered as "1", "-10", etc; reals as "1.0", "-10.0", "1e1",
492: 3.5e-1, etc. The most important difference between the two forms is in
493: division: division of integers truncates: 5/2 = 2; division of reals does
494: not: 5.0/2.0 = 2.5. In mixed expressions, integers are "promoted" to reals
495: before evaluation: 5/2e0 = 2.5. The result of division of a negative integer
496: by a positive one may vary among compilers. Try a test like "print -5/2" to
497: determine if your system chooses -2 or -3 as the answer.
498:
499: The integer expression "1/0" may be used to generate an "undefined" flag,
500: which causes a point to ignored; the `ternary` operator gives an example.
501:
502: The real and imaginary parts of complex expressions are always real, whatever
503: the form in which they are entered: in {3,2} the "3" and "2" are reals, not
504: integers.
505: 3 Functions
506: ?expressions functions
507: ?functions
508: The functions in `gnuplot` are the same as the corresponding functions in
509: the Unix math library, except that all functions accept integer, real, and
510: complex arguments, unless otherwise noted.
511:
512: For those functions that accept or return angles that may be given in either
513: degrees or radians (sin(x), cos(x), tan(x), asin(x), acos(x), atan(x),
514: atan2(x) and arg(z)), the unit may be selected by `set angles`, which
515: defaults to radians.
516:
517: @start table
518: #\begin{tabular}{|ccl|} \hline
519: #\multicolumn{3}{|c|}{Math library functions} \\ \hline \hline
520: #Function & Arguments & Returns \\ \hline
521: %c c l .
522: %Function@Arguments@Returns
523: %_
524: 4 abs
525: ?expressions functions abs
526: ?functions abs
527: ?abs
528: #abs(x) & any & absolute value of $x$, $|x|$; same type \\
529: #abs(x) & complex & length of $x$, $\sqrt{{\mbox{real}(x)^{2} +
530: #\mbox{imag}(x)^{2}}}$ \\
531: %abs(x)@any@absolute value of $x$, $|x|$; same type
532: %abs(x)@complex@length of $x$, $sqrt{roman real (x) sup 2 + roman imag (x) sup 2}$
1.1.1.2 ! maekawa 533: The `abs(x)` function returns the absolute value of its argument. The
! 534: returned value is of the same type as the argument.
1.1 maekawa 535:
536: For complex arguments, abs(x) is defined as the length of x in the complex
537: plane [i.e., sqrt(real(x)**2 + imag(x)**2) ].
538: 4 acos
539: ?expressions functions acos
540: ?functions acos
541: ?acos
542: #acos(x) & any & $\cos^{-1} x$ (inverse cosine) \\
543: %acos(x)@any@$cos sup -1 x$ (inverse cosine)
1.1.1.2 ! maekawa 544: The `acos(x)` function returns the arc cosine (inverse cosine) of its
! 545: argument. `acos` returns its argument in radians or degrees, as selected by
! 546: `set angles`.
1.1 maekawa 547: 4 acosh
548: ?expressions functions acosh
549: ?functions acosh
550: ?acosh
551: #acosh(x) & any & $\cosh^{-1} x$ (inverse hyperbolic cosine) in radians \\
552: %acosh(x)@any@$cosh sup -1 x$ (inverse hyperbolic cosine) in radians
1.1.1.2 ! maekawa 553: The `acosh(x)` function returns the inverse hyperbolic cosine of its argument
! 554: in radians.
1.1 maekawa 555: 4 arg
556: ?expressions functions arg
557: ?functions arg
558: ?arg
559: #arg(x) & complex & the phase of $x$ \\
560: %arg(x)@complex@the phase of $x$
1.1.1.2 ! maekawa 561: The `arg(x)` function returns the phase of a complex number in radians or
1.1 maekawa 562: degrees, as selected by `set angles`.
563: 4 asin
564: ?expressions functions asin
565: ?functions asin
566: ?asin
567: #asin(x) & any & $\sin^{-1} x$ (inverse sin) \\
568: %asin(x)@any@$sin sup -1 x$ (inverse sin)
1.1.1.2 ! maekawa 569: The `asin(x)` function returns the arc sin (inverse sin) of its argument.
1.1 maekawa 570: `asin` returns its argument in radians or degrees, as selected by `set
571: angles`.
572: 4 asinh
573: ?expressions functions asinh
574: ?functions asinh
575: ?asinh
576: #asinh(x) & any & $\sinh^{-1} x$ (inverse hyperbolic sin) in radians \\
577: %asinh(x)@any@$sinh sup -1 x$ (inverse hyperbolic sin) in radians
1.1.1.2 ! maekawa 578: The `asinh(x)` function returns the inverse hyperbolic sin of its argument in
1.1 maekawa 579: radians.
580: 4 atan
581: ?expressions functions atan
582: ?functions atan
583: ?atan
584: #atan(x) & any & $\tan^{-1} x$ (inverse tangent) \\
585: %atan(x)@any@$tan sup -1 x$ (inverse tangent)
1.1.1.2 ! maekawa 586: The `atan(x)` function returns the arc tangent (inverse tangent) of its
1.1 maekawa 587: argument. `atan` returns its argument in radians or degrees, as selected by
588: `set angles`.
589: 4 atan2
590: ?expressions functions atan2
591: ?functions atan2
592: ?atan2
593: #atan2(y,x) & int or real & $\tan^{-1} (y/x)$ (inverse tangent) \\
594: %atan2(y,x)@int or real@$tan sup -1 (y/x)$ (inverse tangent)
1.1.1.2 ! maekawa 595: The `atan2(y,x)` function returns the arc tangent (inverse tangent) of the
! 596: ratio of the real parts of its arguments. `atan2` returns its argument in
! 597: radians or degrees, as selected by `set angles`, in the correct quadrant.
1.1 maekawa 598: 4 atanh
599: ?expressions functions atanh
600: ?functions atanh
1.1.1.2 ! maekawa 601: ?atanh
1.1 maekawa 602: #atanh(x) & any & $\tanh^{-1} x$ (inverse hyperbolic tangent) in radians \\
603: %atanh(x)@any@$tanh sup -1 x$ (inverse hyperbolic tangent) in radians
1.1.1.2 ! maekawa 604: The `atanh(x)` function returns the inverse hyperbolic tangent of its
! 605: argument in radians.
1.1 maekawa 606: 4 besj0
607: ?expressions functions besj0
608: ?functions besj0
609: ?besj0
610: #besj0(x) & int or real & $j_{0}$ Bessel function of $x$, in radians \\
611: %besj0(x)@int or real@$j sub 0$ Bessel function of $x$, in radians
1.1.1.2 ! maekawa 612: The `besj0(x)` function returns the j0th Bessel function of its argument.
1.1 maekawa 613: `besj0` expects its argument to be in radians.
614: 4 besj1
615: ?expressions functions besj1
616: ?functions besj1
617: ?besj1
618: #besj1(x) & int or real & $j_{1}$ Bessel function of $x$, in radians \\
619: %besj1(x)@int or real@$j sub 1$ Bessel function of $x$, in radians
1.1.1.2 ! maekawa 620: The `besj1(x)` function returns the j1st Bessel function of its argument.
1.1 maekawa 621: `besj1` expects its argument to be in radians.
622: 4 besy0
623: ?expressions functions besy0
624: ?functions besy0
625: ?besy0
626: #besy0(x) & int or real & $y_{0}$ Bessel function of $x$, in radians \\
627: %besy0(x)@int or real@$y sub 0$ Bessel function of $x$, in radians
628: The `besy0` function returns the y0th Bessel function of its argument.
629: `besy0` expects its argument to be in radians.
630: 4 besy1
631: ?expressions functions besy1
632: ?functions besy1
633: ?besy1
634: #besy1(x) & int or real & $y_{1}$ Bessel function of $x$, in radians \\
635: %besy1(x)@int or real@$y sub 1$ Bessel function of $x$, in radians
1.1.1.2 ! maekawa 636: The `besy1(x)` function returns the y1st Bessel function of its argument.
1.1 maekawa 637: `besy1` expects its argument to be in radians.
638: 4 ceil
639: ?expressions functions ceil
640: ?functions ceil
641: ?ceil
642: #ceil(x) & any & $\lceil x \rceil$, smallest integer not less than $x$
643: #(real part) \\
644: %ceil(x)@any@$left ceiling x right ceiling$, smallest integer not less than $x$ (real part)
1.1.1.2 ! maekawa 645: The `ceil(x)` function returns the smallest integer that is not less than its
1.1 maekawa 646: argument. For complex numbers, `ceil` returns the smallest integer not less
647: than the real part of its argument.
648: 4 cos
649: ?expressions functions cos
650: ?functions cos
651: ?cos
652: #cos(x) & any & $\cos x$, cosine of $x$ \\
653: %cos(x)@radians@$cos~x$, cosine of $x$
1.1.1.2 ! maekawa 654: The `cos(x)` function returns the cosine of its argument. `cos` accepts its
1.1 maekawa 655: argument in radians or degrees, as selected by `set angles`.
656: 4 cosh
657: ?expressions functions cosh
658: ?functions cosh
659: ?cosh
660: #cosh(x) & any & $\cosh x$, hyperbolic cosine of $x$ in radians \\
661: %cosh(x)@any@$cosh~x$, hyperbolic cosine of $x$ in radians
1.1.1.2 ! maekawa 662: The `cosh(x)` function returns the hyperbolic cosine of its argument. `cosh`
1.1 maekawa 663: expects its argument to be in radians.
664: 4 erf
665: ?expressions functions erf
666: ?functions erf
667: ?erf
668: #erf(x) & any & $\mbox{erf}(\mbox{real}(x))$, error function of real($x$) \\
669: %erf(x)@any@$erf ( roman real (x))$, error function of real ($x$)
1.1.1.2 ! maekawa 670: The `erf(x)` function returns the error function of the real part of its
1.1 maekawa 671: argument. If the argument is a complex value, the imaginary component is
672: ignored.
673: 4 erfc
674: ?expressions functions erfc
675: ?functions erfc
676: ?erfc
677: #erfc(x) & any & $\mbox{erfc}(\mbox{real}(x))$, 1.0 - error function of real($x$) \\
678: %erfc(x)@any@$erfc ( roman real (x))$, 1.0 - error function of real ($x$)
1.1.1.2 ! maekawa 679: The `erfc(x)` function returns 1.0 - the error function of the real part of
! 680: its argument. If the argument is a complex value, the imaginary component is
1.1 maekawa 681: ignored.
682: 4 exp
683: ?expressions functions exp
684: ?functions exp
685: ?exp
686: #exp(x) & any & $e^{x}$, exponential function of $x$ \\
687: %exp(x)@any@$e sup x$, exponential function of $x$
1.1.1.2 ! maekawa 688: The `exp(x)` function returns the exponential function of its argument (`e`
1.1 maekawa 689: raised to the power of its argument). On some implementations (notably
690: suns), exp(-x) returns undefined for very large x. A user-defined function
691: like safe(x) = x<-100 ? 0 : exp(x) might prove useful in these cases.
692: 4 floor
693: ?expressions functions floor
694: ?functions floor
695: ?floor
696: #floor(x) & any & $\lfloor x \rfloor$, largest integer not greater
697: #than $x$ (real part) \\
698: %floor(x)@any@$left floor x right floor$, largest integer not greater than $x$ (real part)
1.1.1.2 ! maekawa 699: The `floor(x)` function returns the largest integer not greater than its
1.1 maekawa 700: argument. For complex numbers, `floor` returns the largest integer not
701: greater than the real part of its argument.
702: 4 gamma
703: ?expressions functions gamma
704: ?functions gamma
705: ?gamma
706: #gamma(x) & any & $\mbox{gamma}(\mbox{real}(x))$, gamma function of real($x$) \\
707: %gamma(x)@any@$GAMMA ( roman real (x))$, gamma function of real ($x$)
1.1.1.2 ! maekawa 708: The `gamma(x)` function returns the gamma function of the real part of its
1.1 maekawa 709: argument. For integer n, gamma(n+1) = n!. If the argument is a complex
710: value, the imaginary component is ignored.
711: 4 ibeta
712: ?expressions functions ibeta
713: ?functions ibeta
714: ?ibeta
715: #ibeta(p,q,x) & any & $\mbox{ibeta}(\mbox{real}(p,q,x))$, ibeta function of real($p$,$q$,$x$) \\
716: %ibeta(p,q,x)@any@$ibeta ( roman real (p,q,x))$, ibeta function of real ($p$,$q$,$x$)
1.1.1.2 ! maekawa 717: The `ibeta(p,q,x)` function returns the incomplete beta function of the real
! 718: parts of its arguments. p, q > 0 and x in [0:1]. If the arguments are
! 719: complex, the imaginary components are ignored.
1.1 maekawa 720: 4 inverf
721: ?expressions functions inverf
722: ?functions inverf
723: ?inverf
724: #inverf(x) & any & inverse error function of real($x$) \\
725: %inverf(x)@any@inverse error function real($x$)
1.1.1.2 ! maekawa 726: The `inverf(x)` function returns the inverse error function of the real part
1.1 maekawa 727: of its argument.
728: 4 igamma
729: ?expressions functions igamma
730: ?functions igamma
731: ?igamma
732: #igamma(a,x) & any & $\mbox{igamma}(\mbox{real}(a,x))$, igamma function of real($a$,$x$) \\
733: %igamma(a,x)@any@$igamma ( roman real (a,x))$, igamma function of real ($a$,$x$)
1.1.1.2 ! maekawa 734: The `igamma(a,x)` function returns the incomplete gamma function of the real
1.1 maekawa 735: parts of its arguments. a > 0 and x >= 0. If the arguments are complex,
736: the imaginary components are ignored.
737: 4 imag
738: ?expressions functions imag
739: ?functions imag
740: ?imag
741: #imag(x) & complex & imaginary part of $x$ as a real number \\
742: %imag(x)@complex@imaginary part of $x$ as a real number
1.1.1.2 ! maekawa 743: The `imag(x)` function returns the imaginary part of its argument as a real
1.1 maekawa 744: number.
745: 4 invnorm
746: ?expressions functions invnorm
747: ?functions invnorm
748: ?invnorm
749: #invnorm(x) & any & inverse normal distribution function of real($x$) \\
750: %invnorm(x)@any@inverse normal distribution function real($x$)
1.1.1.2 ! maekawa 751: The `invnorm(x)` function returns the inverse normal distribution function of
1.1 maekawa 752: the real part of its argument.
753: 4 int
754: ?expressions functions int
755: ?functions int
756: ?int
757: #int(x) & real & integer part of $x$, truncated toward zero \\
758: %int(x)@real@integer part of $x$, truncated toward zero
1.1.1.2 ! maekawa 759: The `int(x)` function returns the integer part of its argument, truncated
1.1 maekawa 760: toward zero.
761: 4 lgamma
762: ?expressions functions lgamma
763: ?functions lgamma
764: ?lgamma
765: #lgamma(x) & any & $\mbox{lgamma}(\mbox{real}(x))$, lgamma function of real($x$) \\
766: %lgamma(x)@any@$lgamma ( roman real (x))$, lgamma function of real ($x$)
1.1.1.2 ! maekawa 767: The `lgamma(x)` function returns the natural logarithm of the gamma function
1.1 maekawa 768: of the real part of its argument. If the argument is a complex value, the
769: imaginary component is ignored.
770: 4 log
771: ?expressions functions log
772: ?functions log
773: ?log
774: #log(x) & any & $\log_{e} x$, natural logarithm (base $e$) of $x$ \\
775: %log(x)@any@$ln~x$, natural logarithm (base $e$) of $x$
1.1.1.2 ! maekawa 776: The `log(x)` function returns the natural logarithm (base `e`) of its
! 777: argument.
1.1 maekawa 778: 4 log10
779: ?expressions functions log10
780: ?functions log10
781: ?log10
782: #log10(x) & any & $\log_{10} x$, logarithm (base $10$) of $x$ \\
783: %log10(x)@any@${log sub 10}~x$, logarithm (base $10$) of $x$
1.1.1.2 ! maekawa 784: The `log10(x)` function returns the logarithm (base 10) of its argument.
1.1 maekawa 785: 4 norm
786: ?expressions functions norm
787: ?functions norm
788: ?norm
789: #norm(x) & any & normal distribution (Gaussian) function of real($x$) \\
790: %norm(x)@any@$norm(x)$, normal distribution function of real($x$)
1.1.1.2 ! maekawa 791: The `norm(x)` function returns the normal distribution function (or Gaussian)
1.1 maekawa 792: of the real part of its argument.
793: 4 rand
794: ?expressions functions rand
795: ?functions rand
796: ?rand
797: #rand(x) & any & $\mbox{rand}(\mbox{real}(x))$, pseudo random number generator \\
798: %rand(x)@any@$rand ( roman real (x))$, pseudo random number generator
1.1.1.2 ! maekawa 799: The `rand(x)` function returns a pseudo random number in the interval [0:1]
1.1 maekawa 800: using the real part of its argument as a seed. If seed < 0, the sequence
801: is (re)initialized. If the argument is a complex value, the imaginary
802: component is ignored.
803: 4 real
804: ?expressions functions real
805: ?functions real
806: ?real
807: #real(x) & any & real part of $x$ \\
808: %real(x)@any@real part of $x$
1.1.1.2 ! maekawa 809: The `real(x)` function returns the real part of its argument.
1.1 maekawa 810: 4 sgn
811: ?expressions functions sgn
812: ?functions sgn
813: ?sgn
814: #sgn(x) & any & 1 if $x>0$, -1 if $x<0$, 0 if $x=0$. imag($x$) ignored \\
815: %sgn(x)@any@1 if $x > 0$, -1 if $x < 0$, 0 if $x = 0$. $roman imag (x)$ ignored
1.1.1.2 ! maekawa 816: The `sgn(x)` function returns 1 if its argument is positive, -1 if its
! 817: argument is negative, and 0 if its argument is 0. If the argument is a
! 818: complex value, the imaginary component is ignored.
1.1 maekawa 819: 4 sin
820: ?expressions functions sin
821: ?functions sin
822: ?sin
823: #sin(x) & any & $\sin x$, sine of $x$ \\
824: %sin(x)@any@$sin~x$, sine of $x$
1.1.1.2 ! maekawa 825: The `sin(x)` function returns the sine of its argument. `sin` expects its
1.1 maekawa 826: argument to be in radians or degrees, as selected by `set angles`.
827: 4 sinh
828: ?expressions functions sinh
829: ?functions sinh
830: ?sinh
831: #sinh(x) & any & $\sinh x$, hyperbolic sine $x$ in radians \\
832: %sinh(x)@any@$sinh~x$, hyperbolic sine $x$ in radians
1.1.1.2 ! maekawa 833: The `sinh(x)` function returns the hyperbolic sine of its argument. `sinh`
1.1 maekawa 834: expects its argument to be in radians.
835: 4 sqrt
836: ?expressions functions sqrt
837: ?functions sqrt
838: ?sqrt
839: #sqrt(x) & any & $\sqrt{x}$, square root of $x$ \\
840: %sqrt(x)@any@$sqrt x $, square root of $x$
1.1.1.2 ! maekawa 841: The `sqrt(x)` function returns the square root of its argument.
1.1 maekawa 842: 4 tan
843: ?expressions functions tan
844: ?functions tan
845: ?tan
846: #tan(x) & any & $\tan x$, tangent of $x$ \\
847: %tan(x)@any@$tan~x$, tangent of $x$
1.1.1.2 ! maekawa 848: The `tan(x)` function returns the tangent of its argument. `tan` expects
1.1 maekawa 849: its argument to be in radians or degrees, as selected by `set angles`.
850: 4 tanh
851: ?expressions functions tanh
852: ?functions tanh
853: ?tanh
854: #tanh(x) & any & $\tanh x$, hyperbolic tangent of $x$ in radians\\
855: %tanh(x)@any@$tanh~x$, hyperbolic tangent of $x$ in radians
1.1.1.2 ! maekawa 856: The `tanh(x)` function returns the hyperbolic tangent of its argument. `tanh`
1.1 maekawa 857: expects its argument to be in radians.
858: @end table
859:
860: A few additional functions are also available.
861:
862: @start table
863: #\begin{tabular}{|ccl|} \hline
864: #\multicolumn{3}{|c|}{other {\bf gnuplot} functions} \\ \hline \hline
865: #Function & Arguments & Returns \\ \hline
866: %c c l .
867: %Function@Arguments@Returns
868: %_
869: 4 column
870: ?expressions functions column
871: ?functions column
872: ?column
873: #column(x) & int & column $x$ during datafile manipulation. \\
874: %column(x)@int@ column $x$ during datafile manipulation.
875: `column(x)` may be used only in expressions as part of `using` manipulations
876: to fits or datafile plots. See `plot datafile using`.
877: 4 tm_hour
878: ?expressions tm_hour
879: ?functions tm_hour
880: #tm\_hour(x) & int & the hour \\
881: %tm_hour(x)@int@the hour
882: The `tm_hour` function interprets its argument as a time, in seconds from
883: 1 Jan 2000. It returns the hour (an integer in the range 0--23) as a real.
884: 4 tm_mday
885: ?expressions tm_mday
886: ?functions tm_mday
887: #tm\_mday(x) & int & the day of the month \\
888: %tm_mday(x)@int@the day of the month
889: The `tm_mday` function interprets its argument as a time, in seconds from
890: 1 Jan 2000. It returns the day of the month (an integer in the range 1--31)
891: as a real.
892: 4 tm_min
893: ?expressions tm_min
894: ?functions tm_min
895: #tm\_min(x) & int & the minute \\
896: %tm_min(x)@int@the minute
897: The `tm_min` function interprets its argument as a time, in seconds from
898: 1 Jan 2000. It returns the minute (an integer in the range 0--59) as a real.
899: 4 tm_mon
900: ?expressions tm_mon
901: ?functions tm_mon
902: #tm\_mon(x) & int & the month \\
903: %tm_mon(x)@int@the month
904: The `tm_mon` function interprets its argument as a time, in seconds from
905: 1 Jan 2000. It returns the month (an integer in the range 1--12) as a real.
906: 4 tm_sec
907: ?expressions tm_sec
908: ?functions tm_sec
909: #tm\_sec(x) & int & the second \\
910: %tm_sec(x)@int@the second
911: The `tm_sec` function interprets its argument as a time, in seconds from
912: 1 Jan 2000. It returns the second (an integer in the range 0--59) as a real.
913: 4 tm_wday
914: ?expressions tm_wday
915: ?functions tm_wday
916: #tm\_wday(x) & int & the day of the week \\
917: %tm_wday(x)@int@the day of the week
918: The `tm_wday` function interprets its argument as a time, in seconds from
919: 1 Jan 2000. It returns the day of the week (an integer in the range 1--7) as
920: a real.
921: 4 tm_yday
922: ?expressions tm_yday
923: ?functions tm_yday
924: #tm\_yday(x) & int & the day of the year \\
925: %tm_yday(x)@int@the day of the year
926: The `tm_yday` function interprets its argument as a time, in seconds from
927: 1 Jan 2000. It returns the day of the year (an integer in the range 1--366)
928: as a real.
929: 4 tm_year
930: ?expressions tm_year
931: ?functions tm_year
932: #tm\_year(x) & int & the year \\
933: %tm_year(x)@int@the year
934: The `tm_year` function interprets its argument as a time, in seconds from
935: 1 Jan 2000. It returns the year (an integer) as a real.
936: 4 valid
937: ?expressions functions valid
938: ?functions valid
939: ?valid
940: #valid(x) & int & test validity of $\mbox{column}(x)$ during datafile manip.\\
941: %valid(x)@int@ test validity of column($x$) during datafile manip.
942: `valid(x)` may be used only in expressions as part of `using` manipulations
943: to fits or datafile plots. See `plot datafile using`.
944: @end table
1.1.1.2 ! maekawa 945: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/airfoil.html">Use of functions and complex variables for airfoils </a>
1.1 maekawa 946: 3 Operators
947: ?expressions operators
948: ?operators
949: The operators in `gnuplot` are the same as the corresponding operators in the
950: C programming language, except that all operators accept integer, real, and
951: complex arguments, unless otherwise noted. The ** operator (exponentiation)
952: is supported, as in FORTRAN.
953:
954: Parentheses may be used to change order of evaluation.
955: 4 Unary
956: ?expressions operators unary
957: ?operators unary
958: ?unary
959: The following is a list of all the unary operators and their usages:
960:
961: @start table - first is interactive cleartext form
962: Symbol Example Explanation
963: - -a unary minus
964: + +a unary plus (no-operation)
965: ~ ~a * one's complement
966: ! !a * logical negation
967: ! a! * factorial
968: $ $3 * call arg/column during `using` manipulation
969: #\begin{tabular}{|ccl|} \hline
970: #\multicolumn{3}{|c|}{Unary Operators}\\ \hline \hline
971: #Symbol & Example & Explanation \\ \hline
972: #\verb@-@ & \verb@-a@ & unary minus \\
973: #\verb@+@ & \verb@+a@ & unary plus (no-operation) \\
974: #\verb@~@ & \verb@~a@ & * one's complement \\
975: #\verb@!@ & \verb@!a@ & * logical negation \\
976: #\verb@!@ & \verb@a!@ & * factorial \\
977: #\verb@$@ & \verb@$3@ & * call arg/column during `using` manipulation \\
978: C ugly hack: doc2ms uses $ as delimiter for eqn's so it doesn't seem to
979: C be able to print them. So we have to typeset this table without using
980: C eqn (at least that's the only solution I found, without any real docs
981: C on *roff and eqn
982: C First, terminate the table doc2ms.c already started:
983: %.TE
984: C ... then turn off eqn delimiters:
985: %.EQ
986: %delim off
987: %.EN
988: C ... and restart the table:
989: %.TS
990: %center box tab (@) ;
991: %c c l .
992: %Symbol@Example@Explanation
993: %_
994: %-@-a@unary minus
995: %+@+a@unary plus (no-operation)
996: %~@~a@* one's complement
997: %!@!a@* logical negation
998: %!@a!@* factorial
999: %$@$3@* call arg/column during `using` manipulation
1000: %_
1001: @end table
1002: (*) Starred explanations indicate that the operator requires an integer
1003: argument.
1004:
1005: Operator precedence is the same as in Fortran and C. As in those languages,
1006: parentheses may be used to change the order of operation. Thus -2**2 = -4,
1007: but (-2)**2 = 4.
1008:
1009: The factorial operator returns a real number to allow a greater range.
1010: 4 Binary
1011: ?expressions operators binary
1012: ?operators binary
1013: ?binary
1014: The following is a list of all the binary operators and their usages:
1015:
1016: @start table - first is interactive cleartext form
1017: Symbol Example Explanation
1018: ** a**b exponentiation
1019: * a*b multiplication
1020: / a/b division
1021: % a%b * modulo
1022: + a+b addition
1023: - a-b subtraction
1024: == a==b equality
1025: != a!=b inequality
1026: < a<b less than
1027: <= a<=b less than or equal to
1028: > a>b greater than
1029: >= a>=b greater than or equal to
1030: & a&b * bitwise AND
1031: ^ a^b * bitwise exclusive OR
1032: | a|b * bitwise inclusive OR
1033: && a&&b * logical AND
1034: || a||b * logical OR
1035: #\begin{tabular}{|ccl|} \hline
1036: #\multicolumn{3}{|c|}{Binary Operators} \\ \hline \hline
1037: #Symbol & Example & Explanation \\ \hline
1038: #\verb~**~ & \verb~a**b~ & exponentiation\\
1039: #\verb~*~ & \verb~a*b~ & multiplication\\
1040: #\verb~/~ & \verb~a/b~ & division\\
1041: #\verb~%~ & \verb~a%b~ & * modulo\\
1042: #\verb~+~ & \verb~a+b~ & addition\\
1043: #\verb~-~ & \verb~a-b~ & subtraction\\
1044: #\verb~==~ & \verb~a==b~ & equality\\
1045: #\verb~!=~ & \verb~a!=b~ & inequality\\
1046: #\verb~<~ & \verb~a<b~ & less than\\
1047: #\verb~<=~ & \verb~a<=b~ & less than or equal to\\
1048: #\verb~>~ & \verb~a>b~ & greater than\\
1049: #\verb~>=~ & \verb~a>=b~ & greater than or equal to\\
1050: #\verb~&~ & \verb~a&b~ & * bitwise AND\\
1051: #\verb~^~ & \verb~a^b~ & * bitwise exclusive OR\\
1052: #\verb~|~ & \verb~a|b~ & * bitwise inclusive OR\\
1053: #\verb~&&~ & \verb~a&&b~ & * logical AND\\
1054: #\verb~||~ & \verb~a||b~ & * logical OR\\
1055: %c c l .
1056: %Symbol@Example@Explanation
1057: %_
1058: %**@a**b@exponentiation
1059: %*@a*b@multiplication
1060: %/@a/b@division
1061: %%@a%b@* modulo
1062: %+@a+b@addition
1063: %-@a-b@subtraction
1064: %==@a==b@equality
1065: %!=@a!=b@inequality
1066: %<@a<b@less than
1067: %<=@a<=b@less than or equal to
1068: %>@a>b@greater than
1069: %>=@a>=b@greater than or equal to
1070: %&@a&b@* bitwise AND
1071: %^@a^b@* bitwise exclusive OR
1072: %|@a|b@* bitwise inclusive OR
1073: %&&@a&&b@* logical AND
1074: %||@a||b@* logical OR
1075:
1076: @end table
1077: (*) Starred explanations indicate that the operator requires integer
1078: arguments.
1079:
1080: Logical AND (&&) and OR (||) short-circuit the way they do in C. That is,
1081: the second `&&` operand is not evaluated if the first is false; the second
1082: `||` operand is not evaluated if the first is true.
1083: 4 Ternary
1084: ?expressions operators ternary
1085: ?operators ternary
1086: ?ternary
1087: There is a single ternary operator:
1088:
1089: @start table - first is interactive cleartext form
1090: Symbol Example Explanation
1091: ?: a?b:c ternary operation
1092: #\begin{tabular}{|ccl|} \hline
1093: #\multicolumn{3}{|c|}{Ternary Operator} \\ \hline \hline
1094: #Symbol & Example & Explanation \\ \hline
1095: #\verb~?:~ & \verb~a?b:c~ & ternary operation\\
1096: %c c l .
1097: %Symbol@Example@Explanation
1098: %_
1099: %?:@a?b:c@* ternary operation
1100:
1101: @end table
1102: The ternary operator behaves as it does in C. The first argument (a), which
1103: must be an integer, is evaluated. If it is true (non-zero), the second
1104: argument (b) is evaluated and returned; otherwise the third argument (c) is
1105: evaluated and returned.
1106:
1107: The ternary operator is very useful both in constructing piecewise functions
1108: and in plotting points only when certain conditions are met.
1109:
1110: Examples:
1111:
1112: Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <= x < 2,
1113: and undefined elsewhere:
1114: f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
1115: plot f(x)
1116: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/ternary.gif" alt="[ternary.gif]" width=640 height=480>
1117: Note that `gnuplot` quietly ignores undefined values, so the final branch of
1118: the function (1/0) will produce no plottable points. Note also that f(x)
1119: will be plotted as a continuous function across the discontinuity if a line
1120: style is used. To plot it discontinuously, create separate functions for the
1121: two pieces. (Parametric functions are also useful for this purpose.)
1122:
1123: For data in a file, plot the average of the data in columns 2 and 3 against
1124: the datum in column 1, but only if the datum in column 4 is non-negative:
1125:
1126: plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )
1127:
1128: Please see `plot data-file using` for an explanation of the `using` syntax.
1129: 3 User-defined
1130: ?expressions user-defined
1131: ?user-defined
1132: ?variables
1133: New user-defined variables and functions of one through five variables may
1134: be declared and used anywhere, including on the `plot` command itself.
1135:
1136: User-defined function syntax:
1137: <func-name>( <dummy1> {,<dummy2>} ... {,<dummy5>} ) = <expression>
1138:
1139: where <expression> is defined in terms of <dummy1> through <dummy5>.
1140:
1141: User-defined variable syntax:
1142: <variable-name> = <constant-expression>
1143:
1144: Examples:
1145: w = 2
1146: q = floor(tan(pi/2 - 0.1))
1147: f(x) = sin(w*x)
1148: sinc(x) = sin(pi*x)/(pi*x)
1149: delta(t) = (t == 0)
1150: ramp(t) = (t > 0) ? t : 0
1151: min(a,b) = (a < b) ? a : b
1152: comb(n,k) = n!/(k!*(n-k)!)
1153: len3d(x,y,z) = sqrt(x*x+y*y+z*z)
1154: plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)
1155:
1156: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/userdefined.gif" alt="[userdefined.gif]" width=640 height=480>
1157: Note that the variable `pi` is already defined. But it is in no way magic;
1158: you may redefine it to be whatever you like.
1159:
1160: Valid names are the same as in most programming languages: they must begin
1161: with a letter, but subsequent characters may be letters, digits, "$", or "_".
1162: Note, however, that the `fit` mechanism uses several variables with names
1163: that begin "FIT_". It is safest to avoid using such names. "FIT_LIMIT",
1164: however, is one that you may wish to redefine. See the documentation
1165: on `fit` for details.
1166:
1167:
1168: See `show functions`, `show variables`, and `fit`.
1169: 2 Glossary
1170: ?glossary
1171: Throughout this document an attempt has been made to maintain consistency of
1172: nomenclature. This cannot be wholly successful because as `gnuplot` has
1173: evolved over time, certain command and keyword names have been adopted that
1174: preclude such perfection. This section contains explanations of the way
1175: some of these terms are used.
1176:
1177: A "page" or "screen" is the entire area addressable by `gnuplot`. On a
1178: monitor, it is the full screen; on a plotter, it is a single sheet of paper.
1179:
1180: A screen may contain one or more "plots". A plot is defined by an abscissa
1181: and an ordinate, although these need not actually appear on it, as well as
1182: the margins and any text written therein.
1183:
1184: A plot contains one "graph". A graph is defined by an abscissa and an
1185: ordinate, although these need not actually appear on it.
1186:
1187: A graph may contain one or more "lines". A line is a single function or
1188: data set. "Line" is also a plotting style. The word will also be used in
1189: sense "a line of text". Presumably the context will remove any ambiguity.
1190:
1191: The lines on a graph may have individual names. These may be listed
1192: together with a sample of the plotting style used to represent them in
1193: the "key", sometimes also called the "legend".
1194:
1195: The word "title" occurs with multiple meanings in `gnuplot`. In this
1196: document, it will always be preceded by the adjective "plot", "line", or
1197: "key" to differentiate among them.
1198:
1199: A graph may have up to four labelled axes. Various commands have the name of
1200: an axis built into their names, such as `set xlabel`. Other commands have
1201: one or more axis names as options, such as `set logscale xy`. The names of
1202: the four axes for these usages are "x" for the axis along the bottom border
1203: of the plot, "y" for the left border, "x2" for the top border, and "y2" for
1204: the right border. "z" also occurs in commands used with 3-d plotting.
1205:
1206: When discussing data files, the term "record" will be resurrected and used
1207: to denote a single line of text in the file, that is, the characters between
1208: newline or end-of-record characters. A "point" is the datum extracted from
1209: a single record. A "datablock" is a set of points from consecutive records,
1210: delimited by blank records. A line, when referred to in the context of a
1211: data file, is a subset of a datablock.
1212: 2 Plotting
1213: ?plotting
1214: There are three `gnuplot` commands which actually create a plot: `plot`,
1215: `splot` and `replot`. `plot` generates 2-d plots, `splot` generates 3-d
1216: plots (actually 2-d projections, of course), and `replot` appends its
1217: arguments to the previous `plot` or `splot` and executes the modified
1218: command.
1219:
1220: Much of the general information about plotting can be found in the discussion
1221: of `plot`; information specific to 3-d can be found in the `splot` section.
1222:
1223: `plot` operates in either rectangular or polar coordinates -- see `set polar`
1224: for details of the latter. `splot` operates only in rectangular coordinates,
1225: but the `set mapping` command allows for a few other coordinate systems to be
1226: treated. In addition, the `using` option allows both `plot` and `splot` to
1227: treat almost any coordinate system you'd care to define.
1228:
1229: `splot` can plot surfaces and contours in addition to points and/or lines.
1230: In addition to `splot`, see `set isosamples` for information about defining
1231: the grid for a 3-d function; `splot datafile` for information about the
1232: requisite file structure for 3-d data values; and `set contour` and `set
1233: cntrparam` for information about contours.
1234: 2 Start-up
1235: ?startup
1236: ?start
1237: ?.gnuplot
1238: When `gnuplot` is run, it looks for an initialization file to load. This
1239: file is called `.gnuplot` on Unix and AmigaOS systems, and `GNUPLOT.INI` on
1240: other systems. If this file is not found in the current directory, the
1241: program will look for it in the home directory (under AmigaOS,
1242: Atari(single)TOS, MS-DOS and OS/2, the environment variable `gnuplot` should
1243: contain the name of this directory). Note: if NOCWDRC is defined during the
1244: installation, `gnuplot` will not read from the current directory.
1245:
1246: If the initialization file is found, `gnuplot` executes the commands in it.
1247: These may be any legal `gnuplot` commands, but typically they are limited to
1248: setting the terminal and defining frequently-used functions or variables.
1249: 2 Substitution
1250: ?substitution
1251: Command-line substitution is specified by a system command enclosed in
1252: backquotes. This command is spawned and the output it produces replaces
1253: the name of the command (and backquotes) on the command line. Some
1254: implementations also support pipes; see `plot data-file special-filenames`.
1255:
1256: Newlines in the output produced by the spawned command are replaced with
1257: blanks.
1258:
1259: Command-line substitution can be used anywhere on the `gnuplot` command
1260: line.
1261:
1262: Example:
1263:
1264: This will run the program `leastsq` and replace `leastsq` (including
1265: backquotes) on the command line with its output:
1266: f(x) = `leastsq`
1267:
1268: or, in VMS
1269: f(x) = `run leastsq`
1270: 2 Syntax
1271: ?syntax
1272: ?specify
1273: ?punctuation
1274: The general rules of syntax and punctuation in `gnuplot` are that keywords
1275: and options are order-dependent. Options and any accompanying parameters are
1276: separated by spaces whereas lists and coordinates are separated by commas.
1277: Ranges are separated by colons and enclosed in brackets [], text and file
1278: names are enclosed in quotes, and a few miscellaneous things are enclosed
1279: in parentheses. Braces {} are used for a few special purposes.
1280:
1281: Commas are used to separate coordinates on the `set` commands `arrow`,
1282: `key`, and `label`; the list of variables being fitted (the list after the
1283: `via` keyword on the `fit` command); lists of discrete contours or the loop
1284: parameters which specify them on the `set cntrparam` command; the arguments
1285: of the `set` commands `dgrid3d`, `dummy`, `isosamples`, `offsets`, `origin`,
1286: `samples`, `size`, `time`, and `view`; lists of tics or the loop parameters
1287: which specify them; the offsets for titles and axis labels; parametric
1288: functions to be used to calculate the x, y, and z coordinates on the `plot`,
1289: `replot` and `splot` commands; and the complete sets of keywords specifying
1290: individual plots (data sets or functions) on the `plot`, `replot` and `splot`
1291: commands.
1292:
1293: Parentheses are used to delimit sets of explicit tics (as opposed to loop
1294: parameters) and to indicate computations in the `using` filter of the `fit`,
1295: `plot`, `replot` and `splot` commands.
1296:
1297: (Parentheses and commas are also used as usual in function notation.)
1298:
1299: Brackets are used to delimit ranges, whether they are given on `set`, `plot`
1300: or `splot` commands.
1301:
1302: Colons are used to separate extrema in `range` specifications (whether they
1303: are given on `set`, `plot` or `splot` commands) and to separate entries in
1304: the `using` filter of the `plot`, `replot`, `splot` and `fit` commands.
1305:
1306: Semicolons are used to separate commands given on a single command line.
1307:
1308: Braces are used in text to be specially processed by some terminals, like
1309: `postscript`. They are also used to denote complex numbers: {3,2} = 3 + 2i.
1310:
1311: Text may be enclosed in single- or double-quotes. Backslash processing of
1312: sequences like \n (newline) and \345 (octal character code) is performed for
1313: double-quoted strings, but not for single-quoted strings.
1314:
1315: The justification is the same for each line of a multi-line string. Thus the
1316: center-justified string
1317: "This is the first line of text.\nThis is the second line."
1318: will produce
1319: This is the first line of text.
1320: This is the second line.
1321: but
1322: 'This is the first line of text.\nThis is the second line.'
1323: will produce
1324: This is the first line of text.\nThis is the second line.
1325:
1326: Filenames may be entered with either single- or double-quotes. In this
1327: manual the command examples generally single-quote filenames and double-quote
1328: other string tokens for clarity.
1329:
1330: At present you should not embed \n inside {} when using the enhanced option
1331: of the postscript terminal.
1332:
1333: The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow a newline to be
1334: specified by \\ in a single-quoted string or \\\\ in a double-quoted string.
1335:
1336: Back-quotes are used to enclose system commands for substitution.
1337: 2 Time/Date data
1338: ?time/date
1339: `gnuplot` supports the use of time and/or date information as input data.
1340: This feature is activated by the commands `set xdata time`, `set ydata time`,
1341: etc.
1342:
1343: Internally all times and dates are converted to the number of seconds from
1344: the year 2000. The command `set timefmt` defines the format for all inputs:
1345: data files, ranges, tics, label positions---in short, anything that accepts a
1346: data value must receive it in this format. Since only one input format can
1347: be in force at a given time, all time/date quantities being input at the same
1348: time must be presented in the same format. Thus if both x and y data in a
1349: file are time/date, they must be in the same format.
1350:
1351: The conversion to and from seconds assumes Universal Time (which is the same
1352: as Greenwich Standard Time). There is no provision for changing the time
1353: zone or for daylight savings. If all your data refer to the same time zone
1354: (and are all either daylight or standard) you don't need to worry about these
1355: things. But if the absolute time is crucial for your application, you'll
1356: need to convert to UT yourself.
1357:
1358: Commands like `show xrange` will re-interpret the integer according to
1359: `timefmt`. If you change `timefmt`, and then `show` the quantity again, it
1360: will be displayed in the new `timefmt`. For that matter, if you give the
1361: deactivation command (like `set xdata`), the quantity will be shown in its
1362: numerical form.
1363:
1364: The command `set format` defines the format that will be used for tic labels,
1365: whether or not the specified axis is time/date.
1366:
1367: If time/date information is to be plotted from a file, the `using` option
1368: _must_ be used on the `plot` or `splot` command. These commands simply use
1369: white space to separate columns, but white space may be embedded within the
1370: time/date string. If you use tabs as a separator, some trial-and-error may
1371: be necessary to discover how your system treats them.
1372:
1373: The following example demonstrates time/date plotting.
1374:
1375: Suppose the file "data" contains records like
1376:
1377: 03/21/95 10:00 6.02e23
1378:
1379: This file can be plotted by
1380:
1381: set xdata time
1382: set timefmt "%m/%d/%y"
1383: set xrange ["03/21/95":"03/22/95"]
1384: set format x "%m/%d"
1385: set timefmt "%m/%d/%y %H:%M"
1386: plot "data" using 1:3
1387:
1388: which will produce xtic labels that look like "03/21".
1389:
1390: See the descriptions of each command for more details.
1391: 1 Commands
1392: ?commands
1393: This section lists the commands acceptable to `gnuplot` in alphabetical
1394: order. Printed versions of this document contain all commands; on-line
1395: versions may not be complete. Indeed, on some systems there may be no
1396: commands at all listed under this heading.
1397:
1398: Note that in most cases unambiguous abbreviations for command names and their
1399: options are permissible, i.e., "`p f(x) w l`" instead of "`plot f(x) with
1400: lines`".
1401:
1402: In the syntax descriptions, braces ({}) denote optional arguments and a
1403: vertical bar (|) separates mutually exclusive choices.
1404: 2 cd
1405: ?commands cd
1406: ?cd
1407: The `cd` command changes the working directory.
1408:
1409: Syntax:
1410: cd '<directory-name>'
1411:
1412: The directory name must be enclosed in quotes.
1413:
1414: Examples:
1415: cd 'subdir'
1416: cd ".."
1417:
1418: DOS users _must_ use single-quotes---backslash [\] has special significance
1419: inside double-quotes. For example,
1420: cd "c:\newdata"
1421: fails, but
1422: cd 'c:\newdata'
1423: works as expected.
1424: 2 call
1425: ?commands call
1426: ?call
1427: The `call` command is identical to the load command with one exception: you
1428: can have up to ten additional parameters to the command (delimited according
1429: to the standard parser rules) which can be substituted into the lines read
1430: from the file. As each line is read from the `call`ed input file, it is
1431: scanned for the sequence `$` (dollar-sign) followed by a digit (0--9). If
1432: found, the sequence is replaced by the corresponding parameter from the
1433: `call` command line. If the parameter was specified as a string in the
1434: `call` line, it is substituted without its enclosing quotes. `$` followed by
1435: any character other than a digit will be that character. E.g. use `$$` to
1436: get a single `$`. Providing more than ten parameters on the `call` command
1437: line will cause an error. A parameter that was not provided substitutes as
1438: nothing. Files being `call`ed may themselves contain `call` or `load`
1439: commands.
1440:
1441: The `call` command _must_ be the last command on a multi-command line.
1442:
1443: Syntax:
1444: call "<input-file>" <parameter-0> <parm-1> ... <parm-9>
1445:
1446: The name of the input file must be enclosed in quotes, and it is recommended
1447: that parameters are similarly enclosed in quotes (future versions of gnuplot
1448: may treat quoted and unquoted arguments differently).
1449:
1450: Example:
1451:
1452: If the file 'calltest.gp' contains the line:
1453: print "p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"
1454:
1455: entering the command:
1456: call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"
1457:
1458: will display:
1459: p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx
1460:
1461: NOTE: there is a clash in syntax with the datafile `using` callback
1462: operator. Use `$$n` or `column(n)` to access column n from a datafile inside
1463: a `call`ed datafile plot.
1464: 2 clear
1465: ?commands clear
1466: ?clear
1467: The `clear` command erases the current screen or output device as specified
1468: by `set output`. This usually generates a formfeed on hardcopy devices. Use
1469: `set terminal` to set the device type.
1470:
1471: For some terminals `clear` erases only the portion of the plotting surface
1472: defined by `set size`, so for these it can be used in conjunction with `set
1473: multiplot` to create an inset.
1474:
1475: Example:
1476: set multiplot
1477: plot sin(x)
1478: set origin 0.5,0.5
1479: set size 0.4,0.4
1480: clear
1481: plot cos(x)
1482: set nomultiplot
1483:
1484: Please see `set multiplot`, `set size`, and `set origin` for details of these
1485: commands.
1486: 2 exit
1487: ?commands exit
1488: ?exit
1489: The commands `exit` and `quit` and the END-OF-FILE character will exit the
1490: current `gnuplot` command file and `load` the next one. See "help
1491: batch/interactive" for more details.
1492:
1493: Each of these commands will clear the output device (as does the `clear`
1494: command) before exiting.
1495: 2 fit
1496: ?commands fit
1497: ?fit
1498: ?least-squares
1499: ?Marquardt
1500: The `fit` command can fit a user-defined function to a set of data points
1501: (x,y) or (x,y,z), using an implementation of the nonlinear least-squares
1502: (NLLS) Marquardt-Levenberg algorithm. Any user-defined variable occurring in
1503: the function body may serve as a fit parameter, but the return type of the
1504: function must be real.
1505:
1506: Syntax:
1507: fit {[xrange] {[yrange]}} <function> '<datafile>'
1508: {datafile-modifiers}
1509: via '<parameter file>' | <var1>{,<var2>,...}
1510:
1511: Ranges may be specified to temporarily limit the data which is to be fitted;
1512: any out-of-range data points are ignored. The syntax is
1513: [{dummy_variable=}{<min>}{:<max>}],
1514: analogous to `plot`; see `plot ranges`.
1515:
1516: <function> is any valid `gnuplot` expression, although it is usual to use a
1517: previously user-defined function of the form f(x) or f(x,y).
1518:
1519: <datafile> is treated as in the `plot` command. All the `plot datafile`
1520: modifiers (`using`, `every`,...) except `smooth` are applicable to `fit`.
1521: See `plot datafile`.
1522:
1523: The default data formats for fitting functions with a single independent
1524: variable, y=f(x), are {x:}y or x:y:s; those formats can be changed with
1525: the datafile `using` qualifier. The third item, (a column number or an
1526: expression), if present, is interpreted as the standard deviation of the
1527: corresponding y value and is used to compute a weight for the datum, 1/s**2.
1528: Otherwise, all data points are weighted equally, with a weight of one.
1529:
1530: To fit a function with two independent variables, z=f(x,y), the required
1531: format is `using` with four items, x:y:z:s. The complete format must be
1532: given---no default columns are assumed for a missing token. Weights for
1533: each data point are evaluated from 's' as above. If error estimates are
1534: not available, a constant value can be specified as a constant expression
1535: (see `plot datafile using`), e.g., `using 1:2:3:(1)`.
1536:
1537: Multiple datasets may be simultaneously fit with functions of one
1538: independent variable by making y a 'pseudo-variable', e.g., the dataline
1539: number, and fitting as two independent variables. See `fit multibranch`.
1540:
1541: The `via` qualifier specifies which parameters are to be adjusted, either
1542: directly, or by referencing a parameter file.
1543:
1544: Examples:
1545: f(x) = a*x**2 + b*x + c
1546: g(x,y) = a*x**2 + b*y**2 + c*x*y
1547: FIT_LIMIT = 1e-6
1548: fit f(x) 'measured.dat' via 'start.par'
1549: fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
1550: fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
1551: fit g(x,y) 'surface.dat' using 1:2:3:(1) via a, b, c
1552:
1553: After each iteration step, detailed information about the current state
1554: of the fit is written to the display. The same information about the
1555: initial and final states is written to a log file, "fit.log". This file
1556: is always appended to, so as to not lose any previous fit history; it
1557: should be deleted or renamed as desired.
1558:
1559: The fit may be interrupted by pressing Ctrl-C (any key but Ctrl-C under
1560: MSDOS and Atari Multitasking Systems). After the current iteration
1561: completes, you have the option to (1) stop the fit and accept the current
1562: parameter values, (2) continue the fit, (3) execute a `gnuplot` command
1563: as specified by the environment variable FIT_SCRIPT. The default for
1564: FIT_SCRIPT is `replot`, so if you had previously plotted both the data
1565: and the fitting function in one graph, you can display the current state
1566: of the fit.
1567:
1568: Once `fit` has finished, the `update` command may be used to store final
1569: values in a file for subsequent use as a parameter file. See `update`
1570: for details.
1571: 3 adjustable parameters
1572: ?commands fit parameters
1573: ?fit parameters
1574: ?commands fit adjustable_parameters
1575: ?fit adjustable_parameters
1576: ?fit_parameters
1577: There are two ways that `via` can specify the parameters to be adjusted,
1578: either directly on the command line or indirectly, by referencing a
1579: parameter file. The two use different means to set initial values.
1580:
1581: Adjustable parameters can be specified by a comma-separated list of variable
1582: names after the `via` keyword. Any variable that is not already defined is
1583: is created with an initial value of 1.0. However, the fit is more likely
1584: to converge rapidly if the variables have been previously declared with more
1585: appropriate starting values.
1586:
1587: In a parameter file, each parameter to be varied and a corresponding initial
1588: value are specified, one per line, in the form
1589: varname = value
1590:
1591: Comments, marked by '#', and blank lines are permissible. The
1592: special form
1593: varname = value # FIXED
1594:
1595: means that the variable is treated as a 'fixed parameter', initialized by the
1596: parameter file, but not adjusted by `fit`. For clarity, it may be useful to
1597: designate variables as fixed parameters so that their values are reported by
1598: `fit`. The keyword `# FIXED` has to appear in exactly this form.
1599:
1600: 3 beginner's guide
1601: ?commands fit beginners_guide
1602: ?fit beginners_guide
1603: ?fit guide
1604: ?fitting
1605: `fit` is used to find a set of parameters that 'best' fits your data to your
1606: user-defined function. The fit is judged on the basis of the the sum of the
1607: squared differences or 'residuals' (SSR) between the input data points and
1608: the function values, evaluated at the same places. This quantity is often
1609: called 'chisquare' (i.e., the Greek letter chi, to the power of 2). The
1610: algorithm attempts to minimize SSR, or more precisely, WSSR, as the residuals
1611: are 'weighted' by the input data errors (or 1.0) before being squared; see
1612: `fit error_estimates` for details.
1613:
1614: That's why it is called 'least-squares fitting'. Let's look at an example
1615: to see what is meant by 'non-linear', but first we had better go over some
1616: terms. Here it is convenient to use z as the dependent variable for
1617: user-defined functions of either one independent variable, z=f(x), or two
1618: independent variables, z=f(x,y). A parameter is a user-defined variable
1619: that `fit` will adjust, i.e., an unknown quantity in the function
1620: declaration. Linearity/non-linearity refers to the relationship of the
1621: dependent variable, z, to the parameters which `fit` is adjusting, not of
1622: z to the independent variables, x and/or y. (To be technical, the
1623: second {and higher} derivatives of the fitting function with respect to
1624: the parameters are zero for a linear least-squares problem).
1625:
1626: For linear least-squares (LLS), the user-defined function will be a sum of
1627: simple functions, not involving any parameters, each multiplied by one
1628: parameter. NLLS handles more complicated functions in which parameters can
1629: be used in a large number of ways. An example that illustrates the
1630: difference between linear and nonlinear least-squares is the Fourier series.
1631: One member may be written as
1632: z=a*sin(c*x) + b*cos(c*x).
1633: If a and b are the unknown parameters and c is constant, then estimating
1634: values of the parameters is a linear least-squares problem. However, if
1635: c is an unknown parameter, the problem is nonlinear.
1636:
1637: In the linear case, parameter values can be determined by comparatively
1638: simple linear algebra, in one direct step. However LLS is a special case
1639: which is also solved along with more general NLLS problems by the iterative
1640: procedure that `gnuplot` uses. `fit` attempts to find the minimum by doing
1641: a search. Each step (iteration) calculates WSSR with a new set of parameter
1642: values. The Marquardt-Levenberg algorithm selects the parameter values for
1643: the next iteration. The process continues until a preset criterium is met,
1644: either (1) the fit has "converged" (the relative change in WSSR is less than
1645: FIT_LIMIT), or (2) it reaches a preset iteration count limit, FIT_MAXITER
1646: (see `fit control variables`). The fit may also be interrupted
1647: and subsequently halted from the keyboard (see `fit`).
1648:
1649: Often the function to be fitted will be based on a model (or theory) that
1650: attempts to describe or predict the behaviour of the data. Then `fit` can
1651: be used to find values for the free parameters of the model, to determine
1652: how well the data fits the model, and to estimate an error range for each
1653: parameter. See `fit error_estimates`.
1654:
1655: Alternatively, in curve-fitting, functions are selected independent of
1656: a model (on the basis of experience as to which are likely to describe
1657: the trend of the data with the desired resolution and a minimum number
1658: of parameters*functions.) The `fit` solution then provides an analytic
1659: representation of the curve.
1660:
1661: However, if all you really want is a smooth curve through your data points,
1662: the `smooth` option to `plot` may be what you've been looking for rather
1663: than `fit`.
1664: 3 error estimates
1665: ?commands fit error_estimate
1666: ?fit error_estimate
1667: ?fit errors
1668: In `fit`, the term "error" is used in two different contexts, data error
1669: estimates and parameter error estimates.
1670:
1671: Data error estimates are used to calculate the relative weight of each data
1672: point when determining the weighted sum of squared residuals, WSSR or
1673: chisquare. They can affect the parameter estimates, since they determine
1674: how much influence the deviation of each data point from the fitted function
1675: has on the final values. Some of the `fit` output information, including
1676: the parameter error estimates, is more meaningful if accurate data error
1677: estimates have been provided.
1678:
1679: The 'statistical overview' describes some of the `fit` output and gives some
1680: background for the 'practical guidelines'.
1681: 4 statistical overview
1682: ?commands fit error statistical_overview
1683: ?fit error statistical_overview
1684: ?statistical_overview
1685: The theory of non-linear least-squares (NLLS) is generally described in terms
1686: of a normal distribution of errors, that is, the input data is assumed to be
1687: a sample from a population having a given mean and a Gaussian (normal)
1688: distribution about the mean with a given standard deviation. For a sample of
1689: sufficiently large size, and knowing the population standard deviation, one
1690: can use the statistics of the chisquare distribution to describe a "goodness
1691: of fit" by looking at the variable often called "chisquare". Here, it is
1692: sufficient to say that a reduced chisquare (chisquare/degrees of freedom,
1693: where degrees of freedom is the number of datapoints less the number of
1694: parameters being fitted) of 1.0 is an indication that the weighted sum of
1695: squared deviations between the fitted function and the data points is the
1696: same as that expected for a random sample from a population characterized by
1697: the function with the current value of the parameters and the given standard
1698: deviations.
1699:
1700: If the standard deviation for the population is not constant, as in counting
1701: statistics where variance = counts, then each point should be individually
1702: weighted when comparing the observed sum of deviations and the expected sum
1703: of deviations.
1704:
1705: At the conclusion `fit` reports 'stdfit', the standard deviation of the fit,
1706: which is the rms of the residuals, and the variance of the residuals, also
1707: called 'reduced chisquare' when the data points are weighted. The number of
1708: degrees of freedom (the number of data points minus the number of fitted
1709: parameters) is used in these estimates because the parameters used in
1710: calculating the residuals of the datapoints were obtained from the same data.
1711:
1712: To estimate confidence levels for the parameters, one can use the minimum
1713: chisquare obtained from the fit and chisquare statistics to determine the
1714: value of chisquare corresponding to the desired confidence level, but
1715: considerably more calculation is required to determine the combinations of
1716: parameters which produce such values.
1717:
1718: Rather than determine confidence intervals, `fit` reports parameter error
1719: estimates which are readily obtained from the variance-covariance matrix
1720: after the final iteration. By convention, these estimates are called
1721: "standard errors" or "asymptotic standard errors", since they are calculated
1722: in the same way as the standard errors (standard deviation of each parameter)
1723: of a linear least-squares problem, even though the statistical conditions for
1724: designating the quantity calculated to be a standard deviation are not
1725: generally valid for the NLLS problem. The asymptotic standard errors are
1726: generally over-optimistic and should not be used for determining confidence
1727: levels, but are useful for qualitative purposes.
1728:
1729: The final solution also produces a correlation matrix, which gives an
1730: indication of the correlation of parameters in the region of the solution;
1731: if one parameter is changed, increasing chisquare, does changing another
1732: compensate? The main diagonal elements, autocorrelation, are all 1; if
1733: all parameters were independent, all other elements would be nearly 0. Two
1734: variables which completely compensate each other would have an off-diagonal
1735: element of unit magnitude, with a sign depending on whether the relation is
1736: proportional or inversely proportional. The smaller the magnitudes of the
1737: off-diagonal elements, the closer the estimates of the standard deviation
1738: of each parameter would be to the asymptotic standard error.
1739: 4 practical guidelines
1740: ?commands fit error practical_guidelines
1741: ?fit error practical_guidelines
1742: ?practical_guidelines
1743: ?guidelines
1744: If you have a basis for assigning weights to each data point, doing so lets
1745: you make use of additional knowledge about your measurements, e.g., take into
1746: account that some points may be more reliable than others. That may affect
1747: the final values of the parameters.
1748:
1749: Weighting the data provides a basis for interpreting the additional `fit`
1750: output after the last iteration. Even if you weight each point equally,
1751: estimating an average standard deviation rather than using a weight of 1
1752: makes WSSR a dimensionless variable, as chisquare is by definition.
1753:
1754: Each fit iteration will display information which can be used to evaluate
1755: the progress of the fit. (An '*' indicates that it did not find a smaller
1756: WSSR and is trying again.) The 'sum of squares of residuals', also called
1757: 'chisquare', is the WSSR between the data and your fitted function; `fit`
1758: has minimized that. At this stage, with weighted data, chisquare is expected
1759: to approach the number of degrees of freedom (data points minus parameters).
1760: The WSSR can be used to calculate the reduced chisquare (WSSR/ndf) or stdfit,
1761: the standard deviation of the fit, sqrt(WSSR/ndf). Both of these are
1762: reported for the final WSSR.
1763:
1764: If the data are unweighted, stdfit is the rms value of the deviation of the
1765: data from the fitted function, in user units.
1766:
1767: If you supplied valid data errors, the number of data points is large enough,
1768: and the model is correct, the reduced chisquare should be about unity. (For
1769: details, look up the 'chi-squared distribution' in your favourite statistics
1770: reference.) If so, there are additional tests, beyond the scope of this
1771: overview, for determining how well the model fits the data.
1772:
1773: A reduced chisquare much larger than 1.0 may be due to incorrect data error
1774: estimates, data errors not normally distributed, systematic measurement
1775: errors, 'outliers', or an incorrect model function. A plot of the residuals,
1776: e.g., `plot 'datafile' using 1:($2-f($1))`, may help to show any systematic
1777: trends. Plotting both the data points and the function may help to suggest
1778: another model.
1779:
1780: Similarly, a reduced chisquare less than 1.0 indicates WSSR is less than that
1781: expected for a random sample from the function with normally distributed
1782: errors. The data error estimates may be too large, the statistical
1783: assumptions may not be justified, or the model function may be too general,
1784: fitting fluctuations in a particular sample in addition to the underlying
1785: trends. In the latter case, a simpler function may be more appropriate.
1786:
1787: You'll have to get used to both `fit` and the kind of problems you apply it
1788: to before you can relate the standard errors to some more practical estimates
1789: of parameter uncertainties or evaluate the significance of the correlation
1790: matrix.
1791:
1792: Note that `fit`, in common with most NLLS implementations, minimizes the
1793: weighted sum of squared distances (y-f(x))**2. It does not provide any means
1794: to account for "errors" in the values of x, only in y. Also, any "outliers"
1795: (data points outside the normal distribution of the model) will have an
1796: exaggerated effect on the solution.
1797: 3 fit controlling
1798: ?commands fit_control
1799: ?fit_control
1800: ?fit control
1801: There are a number of `gnuplot` variables that can be defined to affect
1802: `fit`. Those which can be defined once `gnuplot` is running are listed
1803: under 'control_variables' while those defined before starting `gnuplot`
1804: are listed under 'environment_variables'.
1805: 4 control variables
1806: ?commands fit_control variables
1807: ?fit_control variables
1808: ?fit control variables
1809: The default epsilon limit (1e-5) may be changed by declaring a value for
1810: FIT_LIMIT
1811: When the sum of squared residuals changes between two iteration steps by
1812: a factor less than this number (epsilon), the fit is considered to have
1813: 'converged'.
1814:
1815: The maximum number of iterations may be limited by declaring a value for
1816: FIT_MAXITER
1817: A value of 0 (or not defining it at all) means that there is no limit.
1818:
1819: If you need even more control about the algorithm, and know the
1820: Marquardt-Levenberg algorithm well, there are some more variables to
1821: influence it. The startup value of `lambda` is normally calculated
1822: automatically from the ML-matrix, but if you want to, you may provide
1823: your own one with
1824: FIT_START_LAMBDA
1825: Specifying FIT_START_LAMBDA as zero or less will re-enable the automatic
1826: selection. The variable
1827: FIT_LAMBDA_FACTOR
1828: gives the factor by which `lambda` is increased or decreased whenever
1829: the chi-squared target function increased or decreased significantly.
1830: Setting FIT_LAMBDA_FACTOR to zero re-enables the default factor of
1831: 10.0.
1832:
1833: Oher variables with the FIT_ prefix may be added to `fit`, so it is safer
1834: not to use that prefix for user-defined variables.
1835:
1836: The variables FIT_SKIP and FIT_INDEX were used by earlier releases of
1837: `gnuplot` with a 'fit' patch called `gnufit` and are no longer available.
1838: The datafile `every` modifier provides the functionality of FIT_SKIP.
1839: FIT_INDEX was used for multi-branch fitting, but multi-branch fitting of
1840: one independent variable is now done as a pseudo-3D fit in which the
1841: second independent variable and `using` are used to specify the branch.
1842: See `fit multi-branch`.
1843: 4 environment variables
1844: ?commands fit_control environment
1845: ?fit_control environment
1846: ?fit control environment
1847: The environment variables must be defined before `gnuplot` is executed; how
1848: to do so depends on your operating system.
1849:
1850: FIT_LOG
1851: changes the name (and/or path) of the file to which the fit log will be
1852: written from the default of "fit.log" in the working directory.
1853:
1854: FIT_SCRIPT
1855: specifies a command that may be executed after an user interrupt. The default
1856: is `replot`, but a `plot` or `load` command may be useful to display a plot
1857: customized to highlight the progress of the fit.
1858: 3 multi-branch
1859: ?commands fit multi-branch
1860: ?fit multi-branch
1861: ?multi-branch
1862: ?branch
1863: In multi-branch fitting, multiple data sets can be simultaneously fit with
1864: functions of one independent variable having common parameters by minimizing
1865: the total WSSR. The function and parameters (branch) for each data set are
1866: selected by using a 'pseudo-variable', e.g., either the dataline number (a
1867: 'column' index of -1) or the datafile index (-2), as the second independent
1868: variable.
1869:
1870: Example: Given two exponential decays of the form, z=f(x), each describing
1871: a different data set but having a common decay time, estimate the values of
1872: the parameters. If the datafile has the format x:z:s, then
1873: f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
1874: fit f(x,y) 'datafile' using 1:-1:2:3 via a, b, tau
1875:
1876: For a more complicated example, see the file "hexa.fnc" used by the
1877: "fit.dem" demo.
1878:
1879: Appropriate weighting may be required since unit weights may cause one
1880: branch to predominate if there is a difference in the scale of the dependent
1881: variable. Fitting each branch separately, using the multi-branch solution
1882: as initial values, may give an indication as to the relative effect of each
1883: branch on the joint solution.
1884: 3 starting values
1885: ?commands fit starting_values
1886: ?fit starting_values
1887: ?starting_values
1888: Nonlinear fitting is not guaranteed to converge to the global optimum (the
1889: solution with the smallest sum of squared residuals, SSR), and can get stuck
1890: at a local minimum. The routine has no way to determine that; it is up to
1891: you to judge whether this has happened.
1892:
1893: `fit` may, and often will get "lost" if started far from a solution, where
1894: SSR is large and changing slowly as the parameters are varied, or it may
1895: reach a numerically unstable region (e.g., too large a number causing a
1896: floating point overflow) which results in an "undefined value" message
1897: or `gnuplot` halting.
1898:
1899: To improve the chances of finding the global optimum, you should set the
1900: starting values at least roughly in the vicinity of the solution, e.g.,
1901: within an order of magnitude, if possible. The closer your starting values
1902: are to the solution, the less chance of stopping at another minimum. One way
1903: to find starting values is to plot data and the fitting function on the same
1904: graph and change parameter values and `replot` until reasonable similarity
1905: is reached. The same plot is also useful to check whether the fit stopped at
1906: a minimum with a poor fit.
1907:
1908: Of course, a reasonably good fit is not proof there is not a "better" fit (in
1909: either a statistical sense, characterized by an improved goodness-of-fit
1910: criterion, or a physical sense, with a solution more consistent with the
1911: model.) Depending on the problem, it may be desirable to `fit` with various
1912: sets of starting values, covering a reasonable range for each parameter.
1913: 3 tips
1914: ?commands fit tips
1915: ?fit tips
1916: ?tips
1917: Here are some tips to keep in mind to get the most out of `fit`. They're not
1918: very organized, so you'll have to read them several times until their essence
1919: has sunk in.
1920:
1921: The two forms of the `via` argument to `fit` serve two largely distinct
1922: purposes. The `via "file"` form is best used for (possibly unattended) batch
1923: operation, where you just supply the startup values in a file and can later
1924: use `update` to copy the results back into another (or the same) parameter
1925: file.
1926:
1927: The `via var1, var2, ...` form is best used interactively, where the command
1928: history mechanism may be used to edit the list of parameters to be fitted or
1929: to supply new startup values for the next try. This is particularly useful
1930: for hard problems, where a direct fit to all parameters at once won't work
1931: without good starting values. To find such, you can iterate several times,
1932: fitting only some of the parameters, until the values are close enough to the
1933: goal that the final fit to all parameters at once will work.
1934:
1935: Make sure that there is no mutual dependency among parameters of the function
1936: you are fitting. For example, don't try to fit a*exp(x+b), because
1937: a*exp(x+b)=a*exp(b)*exp(x). Instead, fit either a*exp(x) or exp(x+b).
1938:
1939: A technical issue: the parameters must not be too different in magnitude.
1940: The larger the ratio of the largest and the smallest absolute parameter
1941: values, the slower the fit will converge. If the ratio is close to or above
1942: the inverse of the machine floating point precision, it may take next to
1943: forever to converge, or refuse to converge at all. You will have to adapt
1944: your function to avoid this, e.g., replace 'parameter' by '1e9*parameter' in
1945: the function definition, and divide the starting value by 1e9.
1946:
1947: If you can write your function as a linear combination of simple functions
1948: weighted by the parameters to be fitted, by all means do so. That helps a
1949: lot, because the problem is no longer nonlinear and should converge with only
1950: a small number of iterations, perhaps just one.
1951:
1952: Some prescriptions for analysing data, given in practical experimentation
1953: courses, may have you first fit some functions to your data, perhaps in a
1954: multi-step process of accounting for several aspects of the underlying
1955: theory one by one, and then extract the information you really wanted from
1956: the fitting parameters of those functions. With `fit`, this may often be
1957: done in one step by writing the model function directly in terms of the
1958: desired parameters. Transforming data can also quite often be avoided,
1959: though sometimes at the cost of a more difficult fit problem. If you think
1960: this contradicts the previous paragraph about simplifying the fit function,
1961: you are correct.
1962:
1963: A "singular matrix" message indicates that this implementation of the
1964: Marquardt-Levenberg algorithm can't calculate parameter values for the next
1965: iteration. Try different starting values, writing the function in another
1966: form, or a simpler function.
1967:
1968: Finally, a nice quote from the manual of another fitting package (fudgit),
1969: that kind of summarizes all these issues: "Nonlinear fitting is an art!"
1970: 2 help
1971: ?commands help
1972: ?help
1973: The `help` command displays on-line help. To specify information on a
1974: particular topic use the syntax:
1975:
1976: help {<topic>}
1977:
1978: If <topic> is not specified, a short message is printed about `gnuplot`.
1979: After help for the requested topic is given, a menu of subtopics is given;
1980: help for a subtopic may be requested by typing its name, extending the help
1981: request. After that subtopic has been printed, the request may be extended
1982: again or you may go back one level to the previous topic. Eventually, the
1983: `gnuplot` command line will return.
1984:
1985: If a question mark (?) is given as the topic, the list of topics currently
1986: available is printed on the screen.
1987: 2 if
1988: ?commands if
1989: ?if
1990: The `if` command allows commands to be executed conditionally.
1991:
1992: Syntax:
1993: if (<condition>) <command-line>
1994:
1995: <condition> will be evaluated. If it is true (non-zero), then the command(s)
1996: of the <command-line> will be executed. If <condition> is false (zero), then
1997: the entire <command-line> is ignored. Note that use of `;` to allow multiple
1998: commands on the same line will _not_ end the conditionalized commands.
1999:
2000: Examples:
2001: pi=3
2002: if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1); print pi
2003: will display:
2004: ?Fixing pi!
2005: 3.14159265358979
2006: but
2007: if (1==2) print "Never see this"; print "Or this either"
2008: will not display anything.
2009:
2010: See `reread` for an example of how `if` and `reread` can be used together to
2011: perform a loop.
2012: 2 load
2013: ?commands load
2014: ?load
2015: The `load` command executes each line of the specified input file as if it
2016: had been typed in interactively. Files created by the `save` command can
2017: later be `load`ed. Any text file containing valid commands can be created
2018: and then executed by the `load` command. Files being `load`ed may themselves
2019: contain `load` or `call` commands. See `comment` for information about
2020: comments in commands. To `load` with arguments, see `call`.
2021:
2022: The `load` command _must_ be the last command on a multi-command line.
2023:
2024: Syntax:
2025: load "<input-file>"
2026:
2027: The name of the input file must be enclosed in quotes.
2028:
2029: The special filename "-" may be used to `load` commands from standard input.
2030: This allows a `gnuplot` command file to accept some commands from standard
2031: input. Please see "help batch/interactive" for more details.
2032:
2033: Examples:
2034: load 'work.gnu'
2035: load "func.dat"
2036:
2037: The `load` command is performed implicitly on any file names given as
2038: arguments to `gnuplot`. These are loaded in the order specified, and
2039: then `gnuplot` exits.
2040: 2 pause
2041: ?commands pause
2042: ?pause
2043: The `pause` command displays any text associated with the command and then
2044: waits a specified amount of time or until the carriage return is pressed.
2045: `pause` is especially useful in conjunction with `load` files.
2046:
2047: Syntax:
2048: pause <time> {"<string>"}
2049:
2050: <time> may be any integer constant or expression. Choosing -1 will wait
2051: until a carriage return is hit, zero (0) won't pause at all, and a positive
2052: integer will wait the specified number of seconds. `pause 0` is synonymous
2053: with `print`.
2054:
2055: Note: Since `pause` communicates with the operating system rather than the
2056: graphics, it may behave differently with different device drivers (depending
2057: upon how text and graphics are mixed).
2058:
2059: Examples:
2060: pause -1 # Wait until a carriage return is hit
2061: pause 3 # Wait three seconds
2062: pause -1 "Hit return to continue"
2063: pause 10 "Isn't this pretty? It's a cubic spline."
2064:
2065: 2 plot
2066: ?commands plot
2067: ?plot
2068: `plot` is the primary command for drawing plots with `gnuplot`. It creates
2069: plots of functions and data in many, many ways. `plot` is used to draw 2-d
2070: functions and data; `splot` draws 2-d projections of 3-d surfaces and data.
2071: `plot` and `splot` contain many common features; see `splot` for differences.
2072: Note specifically that `splot`'s `binary` and `matrix` options do not exist
2073: for `plot`.
2074:
2075: Syntax:
2076: plot {<ranges>}
2077: {<function> | {"<datafile>" {datafile-modifiers}}}
2078: {axes <axes>} {<title-spec>} {with <style>}
2079: {, {definitions,} <function> ...}
2080:
2081: where either a <function> or the name of a data file enclosed in quotes is
2082: supplied. A function is a mathematical expression or a pair of mathematical
2083: expressions in parametric mode. The expressions may be defined completely or
2084: in part earlier in the stream of `gnuplot` commands (see `user-defined`).
2085:
2086: It is also possible to define functions and parameters on the `plot` command
2087: itself. This is done merely by isolating them from other items with commas.
2088:
2089: There are four possible sets of axes available; the keyword <axes> is used to
2090: select the axes for which a particular line should be scaled. `x1y1` refers
2091: to the axes on the bottom and left; `x2y2` to those on the top and right;
2092: `x1y2` to those on the bottom and right; and `x2y1` to those on the top and
2093: left. Ranges specified on the `plot` command apply only to the first set of
2094: axes (bottom left).
2095:
2096: Examples:
2097: plot sin(x)
2098: plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
2099: plot [t=1:10] [-pi:pi*2] tan(t), \
2100: "data.1" using (tan($2)):($3/$4) smooth csplines \
2101: axes x1y2 notitle with lines 5
2102:
2103: 3 data-file
2104: ?commands plot datafile
2105: ?plot datafile
2106: ?data-file
2107: ?datafile
2108: ?data
2109: Discrete data contained in a file can be displayed by specifying the name of
2110: the data file (enclosed in single or double quotes) on the `plot` command line.
2111:
2112: Syntax:
2113: plot '<file_name>' {index <index list>}
2114: {every <every list>}
2115: {thru <thru expression>}
2116: {using <using list>}
2117: {smooth <option>}
2118:
2119: The modifiers `index`, `every`, `thru`, `using`, and `smooth` are discussed
2120: separately. In brief, `index` selects which data sets in a multi-data-set
2121: file are to be plotted, `every` specifies which points within a single data
2122: set are to be plotted, `using` determines how the columns within a single
2123: record are to be interpreted (`thru` is a special case of `using`), and
2124: `smooth` allows for simple interpolation and approximation. ('splot' has a
2125: similar syntax, but does not support the `smooth` and `thru` options.)
2126:
2127: Data files should contain at least one data point per record (`using` can
2128: select one data point from the record). Records beginning with `#` (and
2129: also with `!` on VMS) will be treated as comments and ignored. Each data
2130: point represents an (x,y) pair. For `plot`s with error bars (see `set style
2131: errorbars`), each data point is (x,y,ydelta), (x,y,ylow,yhigh), (x,y,xdelta),
2132: (x,y,xlow,xhigh), or (x,y,xlow,xhigh,ylow,yhigh). In all cases, the numbers
2133: on each record of a data file must be separated by white space (one or more
2134: blanks or tabs), unless a format specifier is provided by the `using` option.
2135: This white space divides each record into columns.
2136:
2137: Data may be written in exponential format with the exponent preceded by the
2138: letter e, E, d, D, q, or Q.
2139:
2140: Only one column (the y value) need be provided. If x is omitted, `gnuplot`
2141: provides integer values starting at 0.
2142:
2143: In datafiles, blank records (records with no characters other than blanks and
2144: a newline and/or carriage return) are significant---pairs of blank records
2145: separate `index`es (see `plot datafile index`). Data separated by double
2146: blank records are treated as if they were in separate data files.
2147:
2148: Single blank records designate discontinuities in a `plot`; no line will join
2149: points separated by a blank records (if they are plotted with a line style).
2150:
2151: If autoscaling has been enabled (`set autoscale`), the axes are automatically
2152: extended to include all datapoints, with a whole number of tic marks if tics
2153: are being drawn. This has two consequences: i) For `splot`, the corner of
2154: the surface may not coincide with the corner of the base. In this case, no
2155: vertical line is drawn. ii) When plotting data with the same x range on a
2156: dual-axis graph, the x coordinates may not coincide if the x2tics are not
2157: being drawn. This is because the x axis has been autoextended to a whole
2158: number of tics, but the x2 axis has not. The following example illustrates
2159: the problem:
2160:
2161: reset; plot '-', '-'
2162: 1 1
2163: 19 19
2164: e
2165: 1 1
2166: 19 19
2167: e
2168: 4 every
2169: ?commands plot datafile every
2170: ?plot datafile every
2171: ?plot every
2172: ?data-file every
2173: ?datafile every
2174: ?every
2175: The `every` keyword allows a periodic sampling of a data set to be plotted.
2176:
2177: In the discussion a "point" is a datum defined by a single record in the
2178: file; "block" here will mean the same thing as "datablock" (see `glossary`).
2179:
2180: Syntax:
2181: plot 'file' every {<point_incr>}
2182: {:{<block_incr>}
2183: {:{<start_point>}
2184: {:{<start_block>}
2185: {:{<end_point>}
2186: {:<end_block>}}}}}
2187:
2188: The data points to be plotted are selected according to a loop from
2189: <`start_point`> to <`end_point`> with increment <`point_incr`> and the
2190: blocks according to a loop from <`start_block`> to <`end_block`> with
2191: increment <`block_incr`>.
2192:
2193: The first datum in each block is numbered '0', as is the first block in the
2194: file.
2195:
2196: Note that records containing unplottable information are counted.
2197:
2198: Any of the numbers can be omitted; the increments default to unity, the start
2199: values to the first point or block, and the end values to the last point or
2200: block. If `every` is not specified, all points in all lines are plotted.
2201:
2202: Examples:
2203: every :::3::3 # selects just the fourth block ('0' is first)
2204: every :::::9 # selects the first 10 blocks
2205: every 2:2 # selects every other point in every other block
2206: every ::5::15 # selects points 5 through 15 in each block
1.1.1.2 ! maekawa 2207: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/simple.html">Simple Plot Demos </a>,
1.1 maekawa 2208: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/surfacea/surfacea.html">Non-parametric splot demos </a>, and
2209: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/surfaceb/surfaceb.html">Parametric splot demos.</a>
2210: 4 example datafile
2211: ?commands plot datafile example
2212: ?plot datafile example
2213: ?plot example
2214: ?datafile example
2215: ?data-file example
2216: ?example
2217: This example plots the data in the file "population.dat" and a theoretical
2218: curve:
2219:
2220: pop(x) = 103*exp((1965-x)/10)
2221: plot [1960:1990] 'population.dat', pop(x)
2222:
2223: The file "population.dat" might contain:
2224:
2225: # Gnu population in Antarctica since 1965
2226: 1965 103
2227: 1970 55
2228: 1975 34
2229: 1980 24
2230: 1985 10
2231:
2232: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/population.gif" alt="[population.gif]" width=640 height=480>
2233: 4 index
2234: ?commands plot datafile index
2235: ?plot datafile index
2236: ?plot index
2237: ?data-file index
2238: ?datafile index
2239: ?index
2240: The `index` keyword allows only some of the data sets in a multi-data-set
2241: file to be plotted.
2242:
2243: Syntax:
2244: plot 'file' index <m>{{:<n>}:<p>}
2245:
2246: Data sets are separated by pairs of blank records. `index <m>` selects only
2247: set <m>; `index <m>:<n>` selects sets in the range <m> to <n>; and `index
2248: <m>:<n>:<p>` selects indices <m>, <m>+<p>, <m>+2<p>, etc., but stopping at
2249: <n>. Following C indexing, the index 0 is assigned to the first data set in
2250: the file. Specifying too large an index results in an error message. If
2251: `index` is not specified, all sets are plotted as a single data set.
2252:
2253: Example:
2254: plot 'file' index 4:5
1.1.1.2 ! maekawa 2255: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/multimsh.html"> splot with indices demo. </a>
1.1 maekawa 2256: 4 smooth
2257: ?commands plot datafile smooth
2258: ?plot datafile smooth
2259: ?plot smooth
2260: ?data-file smooth
2261: ?datafile smooth
2262: ?smooth
2263: `gnuplot` includes a few general-purpose routines for interpolation and
2264: approximation of data; these are grouped under the `smooth` option. More
2265: sophisticated data processing may be performed by preprocessing the data
2266: externally or by using `fit` with an appropriate model.
2267:
2268: Syntax:
2269: smooth {unique | csplines | acsplines | bezier | sbezier}
2270:
2271: `unique` plots the data after making them monotonic. Each of the other
2272: routines uses the data to determine the coefficients of a continuous curve
2273: between the endpoints of the data. This curve is then plotted in the same
2274: manner as a function, that is, by finding its value at uniform intervals
2275: along the abscissa (see `set samples`) and connecting these points with
2276: straight line segments (if a line style is chosen).
2277:
2278: If `autoscale` is in effect, the ranges will be computed such that the
2279: plotted curve lies within the borders of the graph.
2280:
2281: If too few points are available to allow the selected option to be applied,
2282: an error message is produced. The minimum number is one for `unique`, four
2283: for `acsplines`, and three for the others.
2284:
2285: The `smooth` options have no effect on function plots.
2286: 5 acsplines
2287: ?commands plot datafile smooth acsplines
2288: ?plot datafile smooth acsplines
2289: ?data-file smooth acsplines
2290: ?datafile smooth acsplines
2291: ?plot smooth acsplines
2292: ?plot acsplines
2293: ?smooth acsplines
2294: ?acsplines
2295: The `acsplines` option approximates the data with a "natural smoothing spline".
2296: After the data are made monotonic in x (see `smooth unique`), a curve is
2297: piecewise constructed from segments of cubic polynomials whose coefficients
2298: are found by the weighting the data points; the weights are taken from the
2299: third column in the data file. That default can be modified by the third
2300: entry in the `using` list, e.g.,
2301: plot 'data-file' using 1:2:(1.0) smooth acsplines
2302:
2303: Qualitatively, the absolute magnitude of the weights determines the number
2304: of segments used to construct the curve. If the weights are large, the
2305: effect of each datum is large and the curve approaches that produced by
2306: connecting consecutive points with natural cubic splines. If the weights are
2307: small, the curve is composed of fewer segments and thus is smoother; the
2308: limiting case is the single segment produced by a weighted linear least
2309: squares fit to all the data. The smoothing weight can be expressed in terms
2310: of errors as a statistical weight for a point divided by a "smoothing factor"
2311: for the curve so that (standard) errors in the file can be used as smoothing
2312: weights.
2313:
2314: Example:
2315: sw(x,S)=1/(x*x*S)
2316: plot 'data_file' using 1:2:(sw($3,100)) smooth acsplines
2317: 5 bezier
2318: ?commands plot datafile smooth bezier
2319: ?plot datafile smooth bezier
2320: ?plot smooth bezier
2321: ?data-file smooth bezier
2322: ?datafile smooth bezier
2323: ?plot bezier
2324: ?smooth bezier
2325: ?bezier
2326: The `bezier` option approximates the data with a Bezier curve of degree n
2327: (the number of data points) that connects the endpoints.
2328: 5 csplines
2329: ?commands plot datafile smooth csplines
2330: ?plot datafile smooth csplines
2331: ?plot smooth csplines
2332: ?data-file smooth csplines
2333: ?datafile smooth csplines
2334: ?plot csplines
2335: ?smooth csplines
2336: ?csplines
2337: The `csplines` option connects consecutive points by natural cubic splines
2338: after rendering the data monotonic (see `smooth unique`).
2339: 5 sbezier
2340: ?commands plot datafile smooth sbezier
2341: ?plot datafile smooth sbezier
2342: ?plot smooth sbezier
2343: ?data-file smooth sbezier
2344: ?datafile smooth sbezier
2345: ?plot sbezier
2346: ?smooth sbezier
2347: ?sbezier
2348: The `sbezier` option first renders the data monotonic (`unique`) and then
2349: applies the `bezier` algorithm.
2350: 5 unique
2351: ?commands plot datafile smooth unique
2352: ?plot datafile smooth unique
2353: ?plot smooth unique
2354: ?data-file smooth unique
2355: ?datafile smooth unique
2356: ?plot unique
2357: ?smooth unique
2358: ?unique
2359: The `unique` option makes the data monotonic in x; points with the same
2360: x-value are replaced by a single point having the average y-value. The
2361: resulting points are then connected by straight line segments.
1.1.1.2 ! maekawa 2362: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/mgr.html"> See demos. </a>
1.1 maekawa 2363: 4 special-filenames
2364: ?commands plot datafile special-filenames
2365: ?plot datafile special-filenames
2366: ?plot special-filenames
2367: ?datafile special-filenames
2368: ?special-filenames
2369: A special filename of `'-'` specifies that the data are inline; i.e., they
2370: follow the command. Only the data follow the command; `plot` options like
2371: filters, titles, and line styles remain on the 'plot' command line. This is
2372: similar to << in unix shell script, and $DECK in VMS DCL. The data are
2373: entered as though they are being read from a file, one data point per record.
2374: The letter "e" at the start of the first column terminates data entry. The
2375: `using` option can be applied to these data---using it to filter them through
2376: a function might make sense, but selecting columns probably doesn't!
2377:
2378: `'-'` is intended for situations where it is useful to have data and commands
2379: together, e.g., when `gnuplot` is run as a sub-process of some front-end
2380: application. Some of the demos, for example, might use this feature. While
2381: `plot` options such as `index` and `every` are recognized, their use forces
2382: you to enter data that won't be used. For example, while
2383:
2384: plot '-' index 0, '-' index 1
2385: 2
2386: 4
2387: 6
2388:
2389:
2390: 10
2391: 12
2392: 14
2393: e
2394: 2
2395: 4
2396: 6
2397:
2398:
2399: 10
2400: 12
2401: 14
2402: e
2403:
2404: does indeed work,
2405:
2406: plot '-', '-'
2407: 2
2408: 4
2409: 6
2410: e
2411: 10
2412: 12
2413: 14
2414: e
2415:
2416: is a lot easier to type.
2417:
2418: If you use `'-'` with `replot`, you may need to enter the data more than once
2419: (see `replot`).
2420:
2421: A blank filename ('') specifies that the previous filename should be reused.
2422: This can be useful with things like
2423:
2424: plot 'a/very/long/filename' using 1:2, '' using 1:3, '' using 1:4
2425:
2426: (If you use both `'-'` and `''` on the same `plot` command, you'll need to
2427: have two sets of inline data, as in the example above.)
2428:
2429: On some computer systems with a popen function (Unix), the datafile can be
2430: piped through a shell command by starting the file name with a '<'. For
2431: example,
2432:
2433: pop(x) = 103*exp(-x/10)
2434: plot "< awk '{print $1-1965, $2}' population.dat", pop(x)
2435:
2436: would plot the same information as the first population example but with
2437: years since 1965 as the x axis. If you want to execute this example, you
2438: have to delete all comments from the data file above or substitute the
2439: following command for the first part of the command above (the part up to
2440: the comma):
2441:
2442: plot "< awk '$0 !~ /^#/ {print $1-1965, $2}' population.dat"
2443:
2444: While this approach is most flexible, it is possible to achieve simple
2445: filtering with the `using` or `thru` keywords.
2446: 4 thru
2447: ?commands plot datafile thru
2448: ?plot datafile thru
2449: ?plot thru
2450: ?data-file thru
2451: ?datafile thru
2452: ?thru
2453: The `thru` function is provided for backward compatibility.
2454:
2455: Syntax:
2456: plot 'file' thru f(x)
2457:
2458: It is equivalent to:
2459:
2460: plot 'file' using 1:(f($2))
2461:
2462: While the latter appears more complex, it is much more flexible. The more
2463: natural
2464:
2465: plot 'file' thru f(y)
2466:
2467: also works (i.e. you can use y as the dummy variable).
2468:
2469: `thru` is parsed for `splot` and `fit` but has no effect.
2470: 4 using
2471: ?commands plot datafile using
2472: ?plot datafile using
2473: ?plot using
2474: ?data-file using
2475: ?datafile using
2476: ?using
2477: The most common datafile modifier is `using`.
2478:
2479: Syntax:
2480: plot 'file' using {<entry> {:<entry> {:<entry> ...}}} {'format'}
2481:
2482: If a format is specified, each datafile record is read using the C library's
2483: 'scanf' function, with the specified format string. Otherwise the record is
2484: read and broken into columns at spaces or tabs. A format cannot be specified
2485: if time-format data is being used (this must be done by `set data time`).
2486:
2487: The resulting array of data is then sorted into columns according to the
2488: entries. Each <entry> may be a simple column number, which selects the
2489: datum, an expression enclosed in parentheses, or empty. The expression can
2490: use $1 to access the first item read, $2 for the second item, and so on. It
2491: can also use `column(x)` and `valid(x)` where x is an arbitrary expression
2492: resulting in an integer. `column(x)` returns the x'th datum; `valid(x)`
2493: tests that the datum in the x'th column is a valid number. A column number
2494: of 0 generates a number increasing (from zero) with each point, and is reset
2495: upon encountering two blank records. A column number of -1 gives the
2496: dataline number, which starts at 0, increments at single blank records, and
2497: is reset at double blank records. A column number of -2 gives the index
2498: number, which is incremented only when two blank records are found. An empty
2499: <entry> will default to its order in the list of entries. For example,
2500: `using ::4` is interpreted as `using 1:2:4`.
2501:
2502: N.B.---the `call` command also uses $'s as a special character. See `call`
2503: for details about how to include a column number in a `call` argument list.
2504:
2505: If the `using` list has but a single entry, that <entry> will be used for y
2506: and the data point number is used for x; for example, "`plot 'file' using 1`"
2507: is identical to "`plot 'file' using 0:1`". If the `using` list has two
2508: entries, these will be used for x and y. Additional entries are usually
2509: errors in x and/or y. See `set style` for details about plotting styles that
2510: make use of error information, and `fit` for use of error information in
2511: curve fitting.
2512:
2513: 'scanf' accepts several numerical specifications but `gnuplot` requires all
2514: inputs to be double-precision floating-point variables, so `lf` is the only
2515: permissible specifier. 'scanf' expects to see white space---a blank, tab
2516: ("\t"), newline ("\n"), or formfeed ("\f")---between numbers; anything else
2517: in the input stream must be explicitly skipped.
2518:
2519: Note that the use of "\t", "\n", or "\f" or requires use of double-quotes
2520: rather than single-quotes.
2521:
2522: Examples:
2523:
2524: This creates a plot of the sum of the 2nd and 3rd data against the first:
2525: (The format string specifies comma- rather than space-separated columns.)
2526: plot 'file' using 1:($2+$3) '%lf,%lf,%lf'
2527:
2528: In this example the data are read from the file "MyData" using a more
2529: complicated format:
2530: plot 'MyData' using "%*lf%lf%*20[^\n]%lf"
2531:
2532: The meaning of this format is:
2533:
2534: %*lf ignore a number
2535: %lf read a double-precision number (x by default)
2536: %*20[^\n] ignore 20 non-newline characters
2537: %lf read a double-precision number (y by default)
2538:
2539: One trick is to use the ternary `?:` operator to filter data:
2540:
2541: plot 'file' using 1:($3>10 ? $2 : 1/0)
2542:
2543: which plots the datum in column two against that in column one provided
2544: the datum in column three exceeds ten. `1/0` is undefined; `gnuplot`
2545: quietly ignores undefined points, so unsuitable points are suppressed.
2546:
2547: In fact, you can use a constant expression for the column number, provided it
2548: doesn't start with an opening parenthesis; constructs like `using
2549: 0+(complicated expression)` can be used. The crucial point is that the
2550: expression is evaluated once if it doesn't start with a left parenthesis, or
2551: once for each data point read if it does.
2552:
2553: If timeseries data are being used, the time can span multiple columns. The
2554: starting column should be specified. Note that the spaces within the time
2555: must be included when calculating starting columns for other data. E.g., if
2556: the first element on a line is a time with an embedded space, the y value
2557: should be specified as column three.
2558:
2559: It should be noted that `plot 'file'`, `plot 'file' using 1:2`, and `plot
2560: 'file' using ($1):($2)` can be subtly different: 1) if `file` has some lines
2561: with one column and some with two, the first will invent x values when they
2562: are missing, the second will quietly ignore the lines with one column, and
2563: the third will store an undefined value for lines with one point (so that in
2564: a plot with lines, no line joins points across the bad point); 2) if a line
2565: contains text at the first column, the first will abort the plot on an error,
2566: but the second and third should quietly skip the garbage.
2567:
2568: In fact, it is often possible to plot a file with lots of lines of garbage at
2569: the top simply by specifying
2570:
2571: plot 'file' using 1:2
2572:
2573: However, if you want to leave text in your data files, it is safer to put the
2574: comment character (#) in the first column of the text lines.
1.1.1.2 ! maekawa 2575: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/using.html"> Feeble using demos. </a>
1.1 maekawa 2576: 3 errorbars
2577: ?commands plot errorbars
2578: ?commands splot errorbars
2579: ?plot errorbars
2580: ?splot errorbars
2581: ?errorbars
2582: Error bars are supported for 2-d data file plots by reading one to four
2583: additional columns (or `using` entries); these additional values are used in
2584: different ways by the various errorbar styles.
2585:
2586: In the default situation, `gnuplot` expects to see three, four, or six
2587: numbers on each line of the data file---either
2588:
2589: (x, y, ydelta),
2590: (x, y, ylow, yhigh),
2591: (x, y, xdelta),
2592: (x, y, xlow, xhigh),
2593: (x, y, xdelta, ydelta), or
2594: (x, y, xlow, xhigh, ylow, yhigh).
2595:
2596: The x coordinate must be specified. The order of the numbers must be
2597: exactly as given above, though the `using` qualifier can manipulate the order
2598: and provide values for missing columns. For example,
2599:
2600: plot 'file' with errorbars
2601: plot 'file' using 1:2:(sqrt($1)) with xerrorbars
2602: plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars
2603:
2604: The last example is for a file containing an unsupported combination of
2605: relative x and absolute y errors. The `using` entry generates absolute x min
2606: and max from the relative error.
2607:
2608: The y error bar is a vertical line plotted from (x, ylow) to (x, yhigh).
2609: If ydelta is specified instead of ylow and yhigh, ylow = y - ydelta and
2610: yhigh = y + ydelta are derived. If there are only two numbers on the record,
2611: yhigh and ylow are both set to y. The x error bar is a horizontal line
2612: computed in the same fashion. To get lines plotted between the data points,
2613: `plot` the data file twice, once with errorbars and once with lines (but
2614: remember to use the `notitle` option on one to avoid two entries in the key).
2615:
2616: The error bars have crossbars at each end unless `set bar` is used (see `set
2617: bar` for details).
2618:
2619: If autoscaling is on, the ranges will be adjusted to include the error bars.
2620: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html"> Errorbar demos. </a>
2621:
2622: See `plot using`, `plot with`, and `set style` for more information.
2623: 3 parametric
2624: ?commands plot parametric
2625: ?commands splot parametric
2626: ?plot parametric
2627: ?splot parametric
2628: ?parametric
2629: When in parametric mode (`set parametric`) mathematical expressions must be
2630: given in pairs for `plot` and in triplets for `splot`.
2631:
2632: Examples:
2633: plot sin(t),t**2
2634: splot cos(u)*cos(v),cos(u)*sin(v),sin(u)
2635:
2636: Data files are plotted as before, except any preceding parametric function
2637: must be fully specified before a data file is given as a plot. In other
2638: words, the x parametric function (`sin(t)` above) and the y parametric
2639: function (`t**2` above) must not be interrupted with any modifiers or data
2640: functions; doing so will generate a syntax error stating that the parametric
2641: function is not fully specified.
2642:
2643: Other modifiers, such as `with` and `title`, may be specified only after the
2644: parametric function has been completed:
2645:
2646: plot sin(t),t**2 title 'Parametric example' with linespoints
1.1.1.2 ! maekawa 2647: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/param.html"> Parametric Mode Demos. </a>
1.1 maekawa 2648: 3 ranges
2649: ?commands plot ranges
2650: ?commands splot ranges
2651: ?plot ranges
2652: ?splot ranges
2653: ?ranges
2654: The optional ranges specify the region of the graph that will be displayed.
2655:
2656: Syntax:
2657: [{<dummy-var>=}{{<min>}:{<max>}}]
2658: [{{<min>}:{<max>}}]
2659:
2660: The first form applies to the independent variable (`xrange` or `trange`, if
2661: in parametric mode). The second form applies to the dependent variable
2662: `yrange` (and `xrange`, too, if in parametric mode). <dummy-var> is a new
2663: name for the independent variable. (The defaults may be changed with `set
2664: dummy`.) The optional <min> and <max> terms can be constant expressions or *.
2665:
2666: In non-parametric mode, the order in which ranges must be given is `xrange`
2667: and `yrange`.
2668:
2669: In parametric mode, the order for the `plot` command is `trange`, `xrange`,
2670: and `yrange`. The following `plot` command shows setting the `trange` to
2671: [-pi:pi], the `xrange` to [-1.3:1.3] and the `yrange` to [-1:1] for the
2672: duration of the graph:
2673:
2674: plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2
2675:
2676: Note that the x2range and y2range cannot be specified here---`set x2range`
2677: and `set y2range` must be used.
2678:
2679: Ranges are interpreted in the order listed above for the appropriate mode.
2680: Once all those needed are specified, no further ones must be listed, but
2681: unneeded ones cannot be skipped---use an empty range `[]` as a placeholder.
2682:
2683: `*` can be used to allow autoscaling of either of min and max. See also
2684: `set autoscale`.
2685:
2686: Ranges specified on the `plot` or `splot` command line affect only that
2687: graph; use the `set xrange`, `set yrange`, etc., commands to change the
2688: default ranges for future graphs.
2689:
2690: With time data, you must provide the range (in the same manner as the time
2691: appears in the datafile) within quotes. `gnuplot` uses the `timefmt` string
2692: to read the value---see `set timefmt`.
2693:
2694: Examples:
2695:
2696: This uses the current ranges:
2697: plot cos(x)
2698:
2699: This sets the x range only:
2700: plot [-10:30] sin(pi*x)/(pi*x)
2701:
2702: This is the same, but uses t as the dummy-variable:
2703: plot [t = -10 :30] sin(pi*t)/(pi*t)
2704:
2705: This sets both the x and y ranges:
2706: plot [-pi:pi] [-3:3] tan(x), 1/x
2707:
2708: This sets only the y range, and turns off autoscaling on both axes:
2709: plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)
2710:
2711: This sets xmax and ymin only:
2712: plot [:200] [-pi:] exp(sin(x))
2713:
2714: This sets the x range for a timeseries:
2715: set timefmt "%d/%m/%y %H:%M"
2716: plot ["1/6/93 12:00":"5/6/93 12:00"] 'timedata.dat'
2717:
2718: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/ranges/ranges.html"> See Demo. </a>
2719: 3 title
2720: ?commands plot title
2721: ?commands splot title
2722: ?plot title
2723: ?splot title
2724: A line title for each function and data set appears in the key, accompanied
2725: by a sample of the line and/or symbol used to represent it. It can be
2726: changed by using the `title` option.
2727:
2728: Syntax:
2729: title "<title>" | notitle
2730:
2731: where <title> is the new title of the line and must be enclosed in quotes.
2732: The quotes will not be shown in the key. A special character may be given as
2733: a backslash followed by its octal value ("\345"). The tab character "\t" is
2734: understood. Note that backslash processing occurs only for strings enclosed
2735: in double quotes---use single quotes to prevent such processing. The newline
2736: character "\n" is not processed in key entries in either type of string.
2737:
2738: The line title and sample can be omitted from the key by using the keyword
2739: `notitle`. A null title (`title ''`) is equivalent to `notitle`. If only
2740: the sample is wanted, use one or more blanks (`title ' '`).
2741:
2742: By default the line title is the function or file name as it appears on the
2743: `plot` command. If it is a file name, any datafile modifiers specified will
2744: be included in the default title.
2745:
2746: The layout of the key itself (position, title justification, etc.) can be
2747: controlled by `set key`. Please see `set key` for details.
2748:
2749: Examples:
2750:
2751: This plots y=x with the title 'x':
2752: plot x
2753:
2754: This plots x squared with title "x^2" and file "data.1" with title
2755: "measured data":
2756: plot x**2 title "x^2", 'data.1' t "measured data"
2757:
2758: This puts an untitled circular border around a polar graph:
2759: set polar; plot my_function(t), 1 notitle
2760: 3 with
2761: ?commands plot with
2762: ?commands splot with
2763: ?commands plot style
2764: ?commands splot style
2765: ?plot with
2766: ?plot style
2767: ?splot with
2768: ?splot style
2769: ?style
2770: ?with
2771: Functions and data may be displayed in one of a large number of styles.
2772: The `with` keyword provides the means of selection.
2773:
2774: Syntax:
2775: with <style> { {linestyle | ls <line_style>}
2776: | {{linetype | lt <line_type>}
2777: {linewidth | lw <line_width>}
2778: {pointtype | pt <point_type>}
2779: {pointsize | ps <point_size>}} }
2780:
2781: where <style> is either `lines`, `points`, `linespoints`, `impulses`, `dots`,
2782: `steps`, `fsteps`, `histeps`, `errorbars`, `xerrorbars`, `yerrorbars`,
2783: `xyerrorbars`, `boxes`, `boxerrorbars`, `boxxyerrorbars`, `financebars`,
2784: `candlesticks` or `vector`. Some of these styles require additional
2785: information. See `set style <style>` for details of each style.
2786:
2787: Default styles are chosen with the `set function style` and `set data style`
2788: commands.
2789:
2790: By default, each function and data file will use a different line type and
2791: point type, up to the maximum number of available types. All terminal
2792: drivers support at least six different point types, and re-use them, in
2793: order, if more are required. The LaTeX driver supplies an additional six
2794: point types (all variants of a circle), and thus will only repeat after 12
2795: curves are plotted with points. The PostScript drivers (`postscript`)
2796: supplies a total of 64.
2797:
2798: If you wish to choose the line or point type for a single plot, <line_type>
2799: and <point_type> may be specified. These are positive integer constants (or
2800: expressions) that specify the line type and point type to be used for the
2801: plot. Use `test` to display the types available for your terminal.
2802:
2803: You may also scale the line width and point size for a plot by using
2804: <line_width> and <point_size>, which are specified relative to the default
2805: values for each terminal. The pointsize may also be altered globally---see
2806: `set pointsize` for details. But note that both <point_size> as set here and
2807: as set by `set pointsize` multiply the default point size---their effects are
2808: not cumulative. That is, `set pointsize 2; plot x w p ps 3` will use points
2809: three times default size, not six.
2810:
2811: If you have defined specific line type/width and point type/size combinations
2812: with `set linestyle`, one of these may be selected by setting <line_style> to
2813: the index of the desired style.
2814:
2815: The keywords may be abbreviated as indicated.
2816:
2817: Note that the `linewidth` and `pointsize` options are not supported by all
2818: terminals.
2819:
2820: Examples:
2821:
2822: This plots sin(x) with impulses:
2823: plot sin(x) with impulses
2824:
2825: This plots x with points, x**2 with the default:
2826: plot x*y w points, x**2 + y**2
2827:
2828: This plots tan(x) with the default function style, file "data.1" with lines:
2829: plot [ ] [-2:5] tan(x), 'data.1' with l
2830:
2831: This plots "leastsq.dat" with impulses:
2832: plot 'leastsq.dat' w i
2833:
2834: This plots the data file "population" with boxes:
2835: plot 'population' with boxes
2836:
2837: This plots "exper.dat" with errorbars and lines connecting the points
2838: (errorbars require three or four columns):
2839: plot 'exper.dat' w lines, 'exper.dat' notitle w errorbars
2840:
2841: This plots sin(x) and cos(x) with linespoints, using the same line type but
2842: different point types:
2843: plot sin(x) with linesp lt 1 pt 3, cos(x) with linesp lt 1 pt 4
2844:
2845: This plots file "data" with points of type 3 and twice usual size:
2846: plot 'data' with points pointtype 3 pointsize 2
2847:
2848: This plots two data sets with lines differing only by weight:
2849: plot 'd1' t "good" w l lt 2 lw 3, 'd2' t "bad" w l lt 2 lw 1
2850:
2851: See `set style` to change the default styles.
2852: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/styles/styles.html"> Styles demos. </a>
2853: 2 print
2854: ?commands print
2855: ?print
2856: The `print` command prints the value of <expression> to the screen. It is
2857: synonymous with `pause 0`. <expression> may be anything that `gnuplot` can
2858: evaluate that produces a number, or it can be a string.
2859:
2860: Syntax:
2861: print <expression> {, <expression>, ...}
2862:
2863: See `expressions`.
2864: 2 pwd
2865: ?commands pwd
2866: ?pwd
2867: The `pwd` command prints the name of the working directory to the screen.
2868: 2 quit
2869: ?commands quit
2870: ?quit
2871: The `exit` and `quit` commands and END-OF-FILE character will exit `gnuplot`.
2872: Each of these commands will clear the output device (as does the `clear`
2873: command) before exiting.
2874: 2 replot
2875: ?commands replot
2876: ?replot
2877: The `replot` command without arguments repeats the last `plot` or `splot`
2878: command. This can be useful for viewing a plot with different `set` options,
2879: or when generating the same plot for several devices.
2880:
2881: Arguments specified after a `replot` command will be added onto the last
2882: `plot` or `splot` command (with an implied ',' separator) before it is
2883: repeated. `replot` accepts the same arguments as the `plot` and `splot`
2884: commands except that ranges cannot be specified. Thus you can use `replot`
2885: to plot a function against the second axes if the previous command was `plot`
2886: but not if it was `splot`, and similarly you can use `replot` to add a plot
2887: from a binary file only if the previous command was `splot`.
2888:
2889: N.B.---use of
2890:
2891: plot '-' ; ... ; replot
2892:
2893: is not recommended. `gnuplot` does not store the inline data internally, so
2894: since `replot` appends new information to the previous `plot` and then
2895: executes the modified command, the `'-'` from the initial `plot` will expect
2896: to read inline data again.
2897:
2898: Note that `replot` does not work in `multiplot` mode, since it reproduces
2899: only the last plot rather than the entire screen.
2900:
2901: See also `command-line-editing` for ways to edit the last `plot` (`splot`)
2902: command.
2903: 2 reread
2904: ?commands reread
2905: ?reread
2906: The `reread` command causes the current `gnuplot` command file, as specified
2907: by a `load` command or on the command line, to be reset to its starting
2908: point before further commands are read from it. This essentially implements
2909: an endless loop of the commands from the beginning of the command file to
2910: the `reread` command. (But this is not necessarily a disaster---`reread` can
2911: be very useful when used in conjunction with `if`. See `if` for details.)
2912: The `reread` command has no effect if input from standard input.
2913:
2914: Examples:
2915:
2916: Suppose the file "looper" contains the commands
2917: a=a+1
2918: plot sin(x*a)
2919: pause -1
2920: if(a<5) reread
2921: and from within `gnuplot` you submit the commands
2922: a=0
2923: load 'looper'
2924: The result will be four plots (separated by the `pause` message).
2925:
2926: Suppose the file "data" contains six columns of numbers with a total yrange
2927: from 0 to 10; the first is x and the next are five different functions of x.
2928: Suppose also that the file "plotter" contains the commands
2929: c_p = c_p+1
2930: plot "$0" using 1:c_p with lines linetype c_p
2931: if(c_p < n_p) reread
2932: and from within `gnuplot` you submit the commands
2933: n_p=6
2934: c_p=1
2935: set nokey
2936: set yrange [0:10]
2937: set multiplot
2938: call 'plotter' 'data'
2939: set nomultiplot
2940: The result is a single graph consisting of five plots. The yrange must be
2941: set explicitly to guarantee that the five separate graphs (drawn on top of
2942: each other in multiplot mode) will have exactly the same axes. The linetype
2943: must be specified; otherwise all the plots would be drawn with the same type.
1.1.1.2 ! maekawa 2944: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/animate.html"> Reread Animation Demo</a>
1.1 maekawa 2945: 2 reset
2946: ?commands reset
2947: ?reset
2948: The `reset` command causes all options that can be set with the `set`
2949: command to take on their default values. The only exceptions are that the
2950: terminal set with `set term` and the output file set with `set output` are
2951: left unchanged. This command is useful, e.g., to restore the default
2952: settings at the end of a command file, or to return to a defined state after
2953: lots of settings have been changed within a command file. Please refer to
2954: the `set` command to see the default values that the various options take.
2955: 2 save
2956: ?commands save
2957: ?save
2958: The `save` command saves user-defined functions, variables, `set` options,
2959: or all three, plus the last `plot` (`splot`) command to the specified file.
2960:
2961: Syntax:
2962: save {<option>} '<filename>'
2963:
2964: where <option> is `functions`, `variables` or `set`. If no option is used,
2965: `gnuplot` saves functions, variables, `set` options and the last `plot`
2966: (`splot`) command.
2967:
2968: `save`d files are written in text format and may be read by the `load`
2969: command.
2970:
2971: The filename must be enclosed in quotes.
2972:
2973: Examples:
2974: save 'work.gnu'
2975: save functions 'func.dat'
2976: save var 'var.dat'
2977: save set 'options.dat'
2978: 2 set-show
2979: ?commands set
2980: ?commands show
2981: ?set
2982: ?show
2983: ?show all
2984: The `set` command can be used to sets _lots_ of options. No screen is
2985: drawn, however, until a `plot`, `splot`, or `replot` command is given.
2986:
2987: The `show` command shows their settings; `show all` shows all the
2988: settings.
2989:
2990: If a variable contains time/date data, `show` will display it according to
2991: the format currently defined by `set timefmt`, even if that was not in effect
2992: when the variable was initially defined.
2993: 3 angles
2994: ?commands set angles
2995: ?commands show angles
2996: ?set angles
2997: ?show angles
2998: ?angles
2999: ?commands set angles degrees
3000: ?set angles degrees
3001: ?angles degrees
3002: ?degrees
3003: By default, `gnuplot` assumes the independent variable in polar graphs is in
3004: units of radians. If `set angles degrees` is specified before `set polar`,
3005: then the default range is [0:360] and the independent variable has units of
3006: degrees. This is particularly useful for plots of data files. The angle
3007: setting also applies to 3-d mapping as set via the `set mapping` command.
3008:
3009: Syntax:
3010: set angles {degrees | radians}
3011: show angles
3012:
3013: The angle specified in `set grid polar` is also read and displayed in the
3014: units specified by `set angles`.
3015:
3016: `set angles` also affects the arguments of the machine-defined functions
3017: sin(x), cos(x) and tan(x), and the outputs of asin(x), acos(x), atan(x),
3018: atan2(x), and arg(x). It has no effect on the arguments of hyperbolic
3019: functions or Bessel functions. However, the output arguments of inverse
3020: hyperbolic functions of complex arguments are affected; if these functions
3021: are used, `set angles radians` must be in effect to maintain consistency
3022: between input and output arguments.
3023:
3024: x={1.0,0.1}
3025: set angles radians
3026: y=sinh(x)
3027: print y #prints {1.16933, 0.154051}
3028: print asinh(y) #prints {1.0, 0.1}
3029: but
3030: set angles degrees
3031: y=sinh(x)
3032: print y #prints {1.16933, 0.154051}
3033: print asinh(y) #prints {57.29578, 5.729578}
1.1.1.2 ! maekawa 3034: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/poldat.html"> Polar plot using `set angles`. </a>
1.1 maekawa 3035: 3 arrow
3036: ?commands set arrow
3037: ?commands set noarrow
3038: ?commands show arrow
3039: ?set arrow
3040: ?set noarrow
3041: ?show arrow
3042: ?arrow
3043: ?noarrow
3044: Arbitrary arrows can be placed on a plot using the `set arrow` command.
3045:
3046: Syntax:
3047: set arrow {<tag>} {from <position>} {to <position>} {{no}head}
3048: { {linestyle | ls <line_style>}
3049: | {linetype | lt <line_type>}
3050: {linewidth | lw <line_width} }
3051: set noarrow {<tag>}
3052: show arrow
3053:
3054: <tag> is an integer that identifies the arrow. If no tag is given, the
3055: lowest unused tag value is assigned automatically. The tag can be used to
3056: delete or change a specific arrow. To change any attribute of an existing
3057: arrow, use the `set arrow` command with the appropriate tag and specify the
3058: parts of the arrow to be changed.
3059:
3060: The <position>s are specified by either x,y or x,y,z, and may be preceded by
3061: `first`, `second`, `graph`, or `screen` to select the coordinate system.
3062: Unspecified coordinates default to 0. The endpoints can be specified in
3063: one of four coordinate systems---`first` or `second` axes, `graph` or
3064: `screen`. See `coordinates` for details. A coordinate system specifier
3065: does not carry over from the "from" position to the "to" position. Arrows
3066: outside the screen boundaries are permitted but may cause device errors.
3067:
3068: Specifying `nohead` produces an arrow drawn without a head---a line segment.
3069: This gives you yet another way to draw a line segment on the plot. By
3070: default, arrows have heads.
3071:
3072: The line style may be selected from a user-defined list of line styles (see
3073: `set linestyle`) or may be defined here by providing values for <line_type>
3074: (an index from the default list of styles) and/or <line_width> (which is a
3075: multiplier for the default width).
3076:
3077: Note, however, that if a user-defined line style has been selected, its
3078: properties (type and width) cannot be altered merely by issuing another
3079: `set arrow` command with the appropriate index and `lt` or `lw`.
3080:
3081: Examples:
3082:
3083: To set an arrow pointing from the origin to (1,2) with user-defined style 5,
3084: use:
3085: set arrow to 1,2 ls 5
3086:
3087: To set an arrow from bottom left of plotting area to (-5,5,3), and tag the
3088: arrow number 3, use:
3089: set arrow 3 from graph 0,0 to -5,5,3
3090:
3091: To change the preceding arrow to end at 1,1,1, without an arrow head and
3092: double its width, use:
3093: set arrow 3 to 1,1,1 nohead lw 2
3094:
3095: To draw a vertical line from the bottom to the top of the graph at x=3, use:
3096: set arrow from 3, graph 0 to 3, graph 1 nohead
3097:
3098: To delete arrow number 2, use:
3099: set noarrow 2
3100:
3101: To delete all arrows, use:
3102: set noarrow
3103:
3104: To show all arrows (in tag order), use:
3105: show arrow
3106: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/arrows/arrows.html"> Arrows Demos. </a>
3107: 3 autoscale
3108: ?commands set autoscale
3109: ?commands set noautoscale
3110: ?commands show autoscale
3111: ?set autoscale
3112: ?set noautoscale
3113: ?show autoscale
3114: ?autoscale
3115: ?noautoscale
3116: Autoscaling may be set individually on the x, y or z axis or globally on all
3117: axes. The default is to autoscale all axes.
3118:
3119: Syntax:
3120: set autoscale {<axes>{min|max}}
3121: set noautoscale {<axes>{min|max}}
3122: show autoscale
3123:
3124: where <axes> is either `x`, `y`, `z`, `x2`, `y2` or `xy`. A keyword with
3125: `min` or `max` appended (this cannot be done with `xy`) tells `gnuplot` to
3126: autoscale just the minimum or maximum of that axis. If no keyword is given,
3127: all axes are autoscaled.
3128:
3129: When autoscaling, the axis range is automatically computed and the dependent
3130: axis (y for a `plot` and z for `splot`) is scaled to include the range of the
3131: function or data being plotted.
3132:
3133: If autoscaling of the dependent axis (y or z) is not set, the current y or z
3134: range is used.
3135:
3136: Autoscaling the independent variables (x for `plot` and x,y for `splot`) is a
3137: request to set the domain to match any data file being plotted. If there are
3138: no data files, autoscaling an independent variable has no effect. In other
3139: words, in the absence of a data file, functions alone do not affect the x
3140: range (or the y range if plotting z = f(x,y)).
3141:
3142: Please see `set xrange` for additional information about ranges.
3143:
3144: The behavior of autoscaling remains consistent in parametric mode, (see `set
3145: parametric`). However, there are more dependent variables and hence more
3146: control over x, y, and z axis scales. In parametric mode, the independent or
3147: dummy variable is t for `plot`s and u,v for `splot`s. `autoscale` in
3148: parametric mode, then, controls all ranges (t, u, v, x, y, and z) and allows
3149: x, y, and z to be fully autoscaled.
3150:
3151: Autoscaling works the same way for polar mode as it does for parametric mode
3152: for `plot`, with the extension that in polar mode `set dummy` can be used to
3153: change the independent variable from t (see `set dummy`).
3154:
3155: When tics are displayed on second axes but no plot has been specified for
3156: those axes, x2range and y2range are inherited from xrange and yrange. This
3157: is done _before_ xrange and yrange are autoextended to a whole number of
3158: tics, which can cause unexpected results.
3159:
3160: Examples:
3161:
3162: This sets autoscaling of the y axis (other axes are not affected):
3163: set autoscale y
3164:
3165: This sets autoscaling only for the minimum of the y axis (the maximum of the
3166: y axis and the other axes are not affected):
3167: set autoscale ymin
3168:
3169: This sets autoscaling of the x and y axes:
3170: set autoscale xy
3171:
3172: This sets autoscaling of the x, y, z, x2 and y2 axes:
3173: set autoscale
3174:
3175: This disables autoscaling of the x, y, z, x2 and y2 axes:
3176: set noautoscale
3177:
3178: This disables autoscaling of the z axis only:
3179: set noautoscale z
3180: 4 parametric mode
3181: ?commands set autoscale parametric
3182: ?set autoscale parametric
3183: ?set autoscale t
3184: When in parametric mode (`set parametric`), the xrange is as fully scalable
3185: as the y range. In other words, in parametric mode the x axis can be
3186: automatically scaled to fit the range of the parametric function that is
3187: being plotted. Of course, the y axis can also be automatically scaled just
3188: as in the non-parametric case. If autoscaling on the x axis is not set, the
3189: current x range is used.
3190:
3191: Data files are plotted the same in parametric and non-parametric mode.
3192: However, there is a difference in mixed function and data plots: in
3193: non-parametric mode with autoscaled x, the x range of the datafile controls
3194: the x range of the functions; in parametric mode it has no influence.
3195:
3196: For completeness a last command `set autoscale t` is accepted. However, the
3197: effect of this "scaling" is very minor. When `gnuplot` determines that the
3198: t range would be empty, it makes a small adjustment if autoscaling is true.
3199: Otherwise, `gnuplot` gives an error. Such behavior may, in fact, not be very
3200: useful and the command `set autoscale t` is certainly questionable.
3201:
3202: `splot` extends the above ideas as you would expect. If autoscaling is set,
3203: then x, y, and z ranges are computed and each axis scaled to fit the
3204: resulting data.
3205: 4 polar mode
3206: ?commands set autoscale polar
3207: ?set autoscale polar
3208: ?set autoscale t
3209: When in polar mode (`set polar`), the xrange and the yrange are both found
3210: from the polar coordinates, and thus they can both be automatically scaled.
3211: In other words, in polar mode both the x and y axes can be automatically
3212: scaled to fit the ranges of the polar function that is being plotted.
3213:
3214: When plotting functions in polar mode, the rrange may be autoscaled. When
3215: plotting data files in polar mode, the trange may also be autoscaled. Note
3216: that if the trange is contained within one quadrant, autoscaling will produce
3217: a polar plot of only that single quadrant.
3218:
3219: Explicitly setting one or two ranges but not others may lead to unexpected
3220: results.
1.1.1.2 ! maekawa 3221: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/poldat.html"> See polar demos </a>
1.1 maekawa 3222: 3 bar
3223: ?commands set bar
3224: ?commands show bar
3225: ?set bar
3226: ?show bar
3227: The `set bar` command controls the tics at the ends of errorbars.
3228:
3229: Syntax:
3230: set bar {small | large | <size>}
3231: show bar
3232:
3233: `small` is a synonym for 0.0, and `large` for 1.0.
3234: The default is 1.0 if no size is given.
3235: 3 bmargin
3236: ?commands set bmargin
3237: ?set bmargin
3238: ?bmargin
3239: The command `set bmargin` sets the size of the bottom margin. Please see
3240: `set margin` for details.
3241: 3 border
3242: ?commands set border
3243: ?commands set noborder
3244: ?commands show border
3245: ?set border
3246: ?set noborder
3247: ?show border
3248: ?border
3249: ?noborder
3250: The `set border` and `set noborder` commands control the display of the graph
3251: borders for the `plot` and `splot` commands.
3252:
3253: Syntax:
3254: set border {<integer> { {linestyle | ls <line_style>}
3255: | {linetype | lt <line_type> }
3256: {linewidth | lw <line_width>} } }
3257: set noborder
3258: show border
3259:
3260: The borders are encoded in a 12-bit integer: the bottom four bits control the
3261: border for `plot` and the sides of the base for `splot`; The next four bits
3262: control the verticals in `splot`; the top four bits control the edges on top
3263: of the `splot`. In detail, the `<integer>` should be the sum of the
3264: appropriate entries from the following table:
3265:
3266: @start table - first is interactive cleartext form
3267: plot border splot splot
3268: Side splot base verticals top
3269: bottom (south) 1 16 256
3270: left (west) 2 32 512
3271: top (north) 4 64 1024
3272: right (east) 8 128 2048
3273: #\begin{tabular}{|cc|ccc|} \hline
3274: #\multicolumn{5}{|c|}{Graph Border Encoding} \\ \hline \hline
3275: # & & \multicolumn{3}{|c|}{Integer value of selection bit} \\ \cline{3-5}
3276: # & & plot border & splot & splot \\
3277: #\multicolumn{2}{|c|}{Side}& splot base & verticals & top \\ \hline
3278: #bottom & (south) & 1 & 16 & 256 \\
3279: #left & (west) & 2 & 32 & 512 \\
3280: #top & (north) & 4 & 64 & 1024 \\
3281: #right & (east) & 8 & 128 & 2048 \\
3282: %c c c c c .
3283: %@plot border@splot@splot
3284: %@splot base@verticals@top
3285: %_
3286: %bottom (south)@1@16@256
3287: %left (west)@2@32@512
3288: %top (north)@4@64@1024
3289: %right (east)@8@128@2048
3290: @end table
3291:
3292: The default is 31, which is all four sides for `plot`, and base and z axis
3293: for `splot`.
3294:
3295: Using the optional <line_style>, <line_type> and <line_width>
3296: specifiers, the way the border lines are drawn can be influenced
1.1.1.2 ! maekawa 3297: (limited by what the current terminal driver supports). By default,
! 3298: the border is drawn with twice the usual linewidth. The <line_width>
! 3299: specifier scales this default value; for example, `set border 15 lw 2`
! 3300: will produce a border with four times the usual linewidth.
1.1 maekawa 3301:
3302: Various axes or combinations of axes may be added together in the command.
3303:
3304: To have tics on edges other than bottom and left, disable the usual tics and
3305: enable the second axes.
3306:
3307: Examples:
3308:
3309: Draw all borders:
3310: set border
3311:
3312: Draw only the SOUTHWEST borders:
3313: set border 3
3314:
3315: Draw a complete box around a `splot`:
3316: set border 4095
3317:
3318: Draw a partial box, omitting the front vertical:
3319: set border 127+256+512
3320:
3321: Draw only the NORTHEAST borders:
3322: set noxtics; set noytics; set x2tics; set y2tics; set border 12
3323:
3324: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/borders/borders.html"> Borders Demo. </a>
3325: 3 boxwidth
3326: ?commands set boxwidth
3327: ?commands show boxwidth
3328: ?set boxwidth
3329: ?show boxwidth
3330: ?boxwidth
3331: The `set boxwidth` command is used to set the default width of boxes in the
3332: `boxes` and `boxerrorbars` styles.
3333:
3334: Syntax:
3335: set boxwidth {<width>}
3336: show boxwidth
3337:
3338: If a data file is plotted without the width being specified in the third,
3339: fourth, or fifth column (or `using` entry), or if a function is plotted, the
3340: width of each box is set by the `set boxwidth` command. (If a width is given
3341: both in the file and by the `set boxwidth` command, the one in the file is
3342: used.) If the width is not specified in one of these ways, the width of each
3343: box will be calculated automatically so that it touches the adjacent boxes.
3344: In a four-column data set, the fourth column will be interpreted as the box
3345: width unless the width is set to -2.0, in which case the width will be
3346: calculated automatically. See `set style boxerrorbars` for more details.
3347:
3348: To set the box width to automatic use the command
3349: set boxwidth
3350: or, for four-column data,
3351: set boxwidth -2
3352:
3353: The same effect can be achieved with the `using` keyword in `plot`:
3354: plot 'file' using 1:2:3:4:(-2)
3355: 3 clabel
3356: ?commands set clabel
3357: ?commands set noclabel
3358: ?commands show clabel
3359: ?set clabel
3360: ?set noclabel
3361: ?show clabel
3362: ?clabel
3363: ?noclabel
3364: `gnuplot` will vary the linetype used for each contour level when clabel is
3365: set. When this option on (the default), a legend labels each linestyle with
3366: the z level it represents. It is not possible at present to separate the
3367: contour labels from the surface key.
3368:
3369: Syntax:
3370: set clabel {'<format>'}
3371: set noclabel
3372: show clabel
3373:
3374: The default for the format string is %8.3g, which gives three decimal places.
3375: This may produce poor label alignment if the key is altered from its default
3376: configuration.
3377:
3378: The first contour linetype, or only contour linetype when clabel is off, is
3379: the surface linetype +1; contour points are the same style as surface points.
3380:
3381: See also `set contour`.
3382: 3 clip
3383: ?commands set clip
3384: ?commands set noclip
3385: ?commands show clip
3386: ?set clip
3387: ?set noclip
3388: ?show clip
3389: ?clip
3390: ?noclip
3391: `gnuplot` can clip data points and lines that are near the boundaries of a
3392: graph.
3393:
3394: Syntax:
3395: set clip <clip-type>
3396: set noclip <clip-type>
3397: show clip
3398:
3399: Three clip types are supported by `gnuplot`: `points`, `one`, and `two`.
3400: One, two, or all three clip types may be active for a single graph.
3401:
3402: The `points` clip type forces `gnuplot` to clip (actually, not plot at all)
3403: data points that fall within but too close to the boundaries. This is done
3404: so that large symbols used for points will not extend outside the boundary
3405: lines. Without clipping points near the boundaries, the plot may look bad.
3406: Adjusting the x and y ranges may give similar results.
3407:
3408: Setting the `one` clip type causes `gnuplot` to draw a line segment which has
3409: only one of its two endpoints within the graph. Only the in-range portion of
3410: the line is drawn. The alternative is to not draw any portion of the line
3411: segment.
3412:
3413: Some lines may have both endpoints out of range, but pass through the graph.
3414: Setting the `two` clip-type allows the visible portion of these lines to be
3415: drawn.
3416:
3417: In no case is a line drawn outside the graph.
3418:
3419: The defaults are `noclip points`, `clip one`, and `noclip two`.
3420:
3421: To check the state of all forms of clipping, use
3422: show clip
3423:
3424: For backward compatibility with older versions, the following forms are also
3425: permitted:
3426: set clip
3427: set noclip
3428:
3429: `set clip` is synonymous with `set clip points`; `set noclip` turns off all
3430: three types of clipping.
3431: 3 cntrparam
3432: ?commands set cntrparam
3433: ?commands show cntrparam
3434: ?set cntrparam
3435: ?show cntrparam
3436: ?cntrparam
3437: `set cntrparam` controls the generation of contours and their smoothness for
3438: a contour plot. `show contour` displays current settings of `cntrparam` as
3439: well as `contour`.
3440:
3441: Syntax:
3442: set cntrparam { {linear | cubicspline | bspline}
3443: { points <n>} { order <n> }
3444: { levels auto {<n>} | <n>
3445: | discrete <z1> {,<z2>{,<z3>...}}
3446: | incremental <start>, <incr> {,<end>}
3447: }
3448: }
3449: show contour
3450:
3451: This command has two functions. First, it sets the values of z for which
3452: contour points are to be determined (by linear interpolation between data
3453: points or function isosamples.) Second, it controls the way contours are
3454: drawn between the points determined to be of equal z. <n> should be an
3455: integral constant expression and <z1>, <z2> ... any constant expressions.
3456: The parameters are:
3457:
3458: `linear`, `cubicspline`, `bspline`---Controls type of approximation or
3459: interpolation. If `linear`, then straight line segments connect points of
3460: equal z magnitude. If `cubicspline`, then piecewise-linear contours are
3461: interpolated between the same equal z points to form somewhat smoother
3462: contours, but which may undulate. If `bspline`, a guaranteed-smoother curve
3463: is drawn, which only approximates the position of the points of equal-z.
3464:
3465: `points`---Eventually all drawings are done with piecewise-linear strokes.
3466: This number controls the number of line segments used to approximate the
3467: `bspline` or `cubicspline` curve. Number of cubicspline or bspline
3468: segments (strokes) = `points` * number of linear segments.
3469:
3470: `order`---Order of the bspline approximation to be used. The bigger this
3471: order is, the smoother the resulting contour. (Of course, higher order
3472: bspline curves will move further away from the original piecewise linear
3473: data.) This option is relevant for `bspline` mode only. Allowed values are
3474: integers in the range from 2 (linear) to 10.
3475:
3476: `levels`--- Selection of contour levels, controlled by `auto` (default),
3477: `discrete`, `incremental`, and <n>, number of contour levels, limited to
3478: MAX_DISCRETE_LEVELS as defined in plot.h (30 is standard.)
3479:
3480: For `auto`, <n> specifies a nominal number of levels; the actual number will
3481: be adjusted to give simple labels. If the surface is bounded by zmin and zmax,
3482: contours will be generated at integer multiples of dz between zmin and zmax,
3483: where dz is 1, 2, or 5 times some power of ten (like the step between two
3484: tic marks).
3485:
3486: For `levels discrete`, contours will be generated at z = <z1>, <z2> ... as
3487: specified; the number of discrete levels sets the number of contour levels.
3488: In `discrete` mode, any `set cntrparms levels <n>` are ignored.
3489:
3490: For `incremental`, contours are generated at values of z beginning at <start>
3491: and increasing by <increment>, until the number of contours is reached. <end>
3492: is used to determine the number of contour levels, which will be changed by
3493: any subsequent `set cntrparam levels <n>`.
3494:
3495: If the command `set cntrparam` is given without any arguments specified, the
3496: defaults are used: linear, 5 points, order 4, 5 auto levels.
3497:
3498: Examples:
3499: set cntrparam bspline
3500: set cntrparam points 7
3501: set cntrparam order 10
3502:
3503: To select levels automatically, 5 if the level increment criteria are met:
3504: set cntrparam levels auto 5
3505:
3506: To specify discrete levels at .1, .37, and .9:
3507: set cntrparam levels discrete .1,1/exp(1),.9
3508:
3509: To specify levels from 0 to 4 with increment 1:
3510: set cntrparam levels incremental 0,1,4
3511:
3512: To set the number of levels to 10 (changing an incremental end or possibly
3513: the number of auto levels):
3514: set cntrparam levels 10
3515:
3516: To set the start and increment while retaining the number of levels:
3517: set cntrparam levels incremental 100,50
3518:
3519: See also `set contour` for control of where the contours are drawn, and `set
3520: clabel` for control of the format of the contour labels and linetypes.
1.1.1.2 ! maekawa 3521: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/contours.html">Contours Demo</a> and
! 3522: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/discrete.html">contours with User Defined Levels.</a>
1.1 maekawa 3523: 3 contour
3524: ?commands set contour
3525: ?commands set nocontour
3526: ?commands show contour
3527: ?set contour
3528: ?set nocontour
3529: ?show contour
3530: ?contour
3531: ?nocontour
3532: `set contour` enables contour drawing for surfaces. This option is available
3533: for `splot` only.
3534:
3535: Syntax:
3536: set contour {base | surface | both}
3537: set nocontour
3538: show contour
3539:
3540: The three options specify where to draw the contours: `base` draws the
3541: contours on the grid base where the x/ytics are placed, `surface` draws the
3542: contours on the surfaces themselves, and `both` draws the contours on both
3543: the base and the surface. If no option is provided, the default is `base`.
3544:
3545: See also `set cntrparam` for the parameters that affect the drawing of
3546: contours, and `set clabel` for control of labelling of the contours.
3547:
3548: The surface can be switched off (see `set surface`), giving a contour-only
3549: graph. Though it is possible to use `set size` to enlarge the plot to fill
3550: the screen, more control over the output format can be obtained by writing
3551: the contour information to a file, and rereading it as a 2-d datafile plot:
3552:
3553: set nosurface
3554: set contour
3555: set cntrparam ...
3556: set term table
3557: set out 'filename'
3558: splot ...
3559: set out
3560: # contour info now in filename
3561: set term <whatever>
3562: plot 'filename'
3563:
3564: In order to draw contours, the data should be organized as "grid data". In
3565: such a file all the points for a single y-isoline are listed, then all the
3566: points for the next y-isoline, and so on. A single blank line (a line
3567: containing no characters other than blank spaces and a carriage return and/or
3568: a line feed) separates one y-isoline from the next. See also `splot datafile`.
3569:
3570: If contours are desired from non-grid data, `set dgrid3d` can be used to
3571: create an appropriate grid. See `set dgrid3d` for more information.
1.1.1.2 ! maekawa 3572: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/contours.html">Contours Demo</a> and
! 3573: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/discrete.html">contours with User Defined Levels.</a>
1.1 maekawa 3574: 3 data style
3575: ?commands set data style
3576: ?commands show data style
3577: ?set data style
3578: ?show data style
3579: ?data style
3580: The `set data style` command changes the default plotting style for data
3581: plots.
3582:
3583: Syntax:
3584: set data style <style-choice>
3585: show data style
3586:
3587: See `set style` for the choices. If no choice is given, the choices are
3588: listed. `show data style` shows the current default data plotting style.
3589: 3 dgrid3d
3590: ?commands set dgrid3d
3591: ?commands set nodgrid3d
3592: ?commands show dgrid3d
3593: ?set dgrid3d
3594: ?set nodgrid3d
3595: ?show dgrid3d
3596: ?dgrid3d
3597: ?nodgrid3d
3598: The `set dgrid3d` command enables, and can set parameters for, non-grid
3599: to grid data mapping.
3600:
3601: Syntax:
3602: set dgrid3d {<row_size>} {,{<col_size>} {,<norm>}}
3603: set nodgrid3d
3604: show dgrid3d
3605:
3606: By default `dgrid3d` is disabled. When enabled, 3-d data read from a file
3607: are always treated as a scattered data set. A grid with dimensions derived
3608: from a bounding box of the scattered data and size as specified by the
3609: row/col_size parameters is created for plotting and contouring. The grid
3610: is equally spaced in x (rows) and in y (columns); the z values are computed
3611: as weighted averages of the scattered points' z values.
3612:
3613: The third parameter, norm, controls the weighting: Each data point is
3614: weighted inversely by its distance from the grid point raised to the norm
3615: power. (Actually, the weights are given by the inverse of dx^norm + dy^norm,
3616: where dx and dy are the components of the separation of the grid point from
3617: each data point. For some norms that are powers of two, specifically 4, 8,
3618: and 16, the computation is optimized by using the Euclidean distance in the
3619: weight calculation, (dx^2+dx^2)^norm/2. However, any non-negative integer
3620: can be used.)
3621:
3622: The closer the data point is to a grid point, the more effect it has on
3623: that grid point and the larger the value of norm the less effect more
3624: distant data points have on that grid point.
3625:
3626: The `dgrid3d` option is a simple low pass filter that converts scattered
3627: data to a grid data set. More sophisticated approaches to this problem
3628: exist and should be used to preprocess the data outside `gnuplot` if this
3629: simple solution is found inadequate.
3630:
3631: (The z values are found by weighting all data points, not by interpolating
3632: between nearby data points; also edge effects may produce unexpected and/or
3633: undesired results. In some cases, small norm values produce a grid point
3634: reflecting the average of distant data points rather than a local average,
3635: while large values of norm may produce "steps" with several grid points
3636: having the same value as the closest data point, rather than making a smooth
3637: transition between adjacent data points. Some areas of a grid may be filled
3638: by extrapolation, to an arbitrary boundary condition. The variables are
3639: not normalized; consequently the units used for x and y will affect the
3640: relative weights of points in the x and y directions.)
3641:
3642: Examples:
3643: set dgrid3d 10,10,1 # defaults
3644: set dgrid3d ,,4
3645:
3646: The first specifies that a grid of size 10 by 10 is to be constructed using
3647: a norm value of 1 in the weight computation. The second only modifies the
3648: norm, changing it to 4.
1.1.1.2 ! maekawa 3649: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/scatter.html"> Dgrid3d Demo.</a>
1.1 maekawa 3650:
3651: 3 dummy
3652: ?commands set dummy
3653: ?commands show dummy
3654: ?set dummy
3655: ?show dummy
3656: ?dummy
3657: The `set dummy` command changes the default dummy variable names.
3658:
3659: Syntax:
3660: set dummy {<dummy-var>} {,<dummy-var>}
3661: show dummy
3662:
3663: By default, `gnuplot` assumes that the independent, or "dummy", variable for
3664: the `plot` command is "t" if in parametric or polar mode, or "x" otherwise.
3665: Similarly the independent variables for the `splot` command are "u" and "v"
3666: in parametric mode (`splot` cannot be used in polar mode), or "x" and "y"
3667: otherwise.
3668:
3669: It may be more convenient to call a dummy variable by a more physically
3670: meaningful or conventional name. For example, when plotting time functions:
3671:
3672: set dummy t
3673: plot sin(t), cos(t)
3674:
3675: At least one dummy variable must be set on the command; `set dummy` by itself
3676: will generate an error message.
3677:
3678: Examples:
3679: set dummy u,v
3680: set dummy ,s
3681:
3682: The second example sets the second variable to s.
3683: 3 encoding
3684: ?commands set encoding
3685: ?commands show encoding
3686: ?set encoding
3687: ?show encoding
3688: ?encoding
3689: The `set encoding` command selects a character encoding. Valid values are
3690: `default`, which tells a terminal to use its default; `iso_8859_1` (known in
3691: the PostScript world as `ISO-Latin1`), which is used on many Unix workstations
3692: and with MS-Windows; `cp850`, for OS/2; and `cp437`, for MS-DOS.
3693:
3694: Syntax:
3695: set encoding {<value>}
3696: show encoding
3697:
3698: Note that encoding is not supported by all terminal drivers and that
3699: the device must be able to produce the desired non-standard characters.
3700: 3 format
3701: ?commands set format
3702: ?commands show format
3703: ?set format
3704: ?show format
3705: ?format
3706: The format of the tic-mark labels can be set with the `set format` command.
3707:
3708: Syntax:
3709: set format {<axes>} {"<format-string>"}
3710: set format {<axes>} {'<format-string>'}
3711: show format
3712:
3713: where <axes> is either `x`, `y`, `z`, `xy`, `x2`, `y2` or nothing (which is
3714: the same as `xy`). The length of the string representing a tic mark (after
3715: formatting with 'printf') is restricted to 100 characters. If the format
3716: string is omitted, the format will be returned to the default "%g". For
3717: LaTeX users, the format "$%g$" is often desirable. If the empty string "" is
3718: used, no label will be plotted with each tic, though the tic mark will still
3719: be plotted. To eliminate all tic marks, use `set noxtics` or `set noytics`.
3720:
3721: Newline (\n) is accepted in the format string. Use double-quotes rather than
3722: single-quotes to enable such interpretation. See also `syntax`.
3723:
3724: The default format for both axes is "%g", but other formats such as "%.2f" or
3725: "%3.0em" are often desirable. Anything accepted by 'printf' when given a
3726: double precision number, and accepted by the terminal, will work. Some other
3727: options have been added. If the format string looks like a floating point
3728: format, then `gnuplot` tries to construct a reasonable format.
3729:
3730: Characters not preceded by "%" are printed verbatim. Thus you can include
3731: spaces and labels in your format string, such as "%g m", which will put " m"
3732: after each number. If you want "%" itself, double it: "%g %%".
3733:
3734: See also `set xtics` for more information about tic labels.
1.1.1.2 ! maekawa 3735: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/electron.html"> See demo. </a>
1.1 maekawa 3736: 4 format specifiers
3737: ?commands set format specifiers
3738: ?set format specifiers
3739: ?format specifiers
3740: ?format_specifiers
3741: The acceptable formats (if not in time/date mode) are:
3742:
3743: @start table - first is interactive cleartext form
3744: Format Explanation
3745: %f floating point notation
3746: %e or %E exponential notation; an "e" or "E" before the power
3747: %g or %G the shorter of %e (or %E) and %f
3748: %x or %X hex
3749: %o or %O octal
3750: %t mantissa to base 10
3751: %l mantissa to base of current logscale
3752: %s mantissa to base of current logscale; scientific power
3753: %T power to base 10
3754: %L power to base of current logscale
3755: %S scientific power
3756: %c character replacement for scientific power
3757: %P multiple of pi
3758: #\begin{tabular}{|cl|} \hline
3759: #\multicolumn{2}{|c|}{Tic-mark label numerical format specifiers}\\
3760: #\hline \hline
3761: #Format & Explanation \\ \hline
3762: #\verb@%f@ & floating point notation \\
3763: #\verb@%e@ or \verb@%E@ & exponential notation; an "e" or "E" before the power \\
3764: #\verb@%g@ or \verb@%G@ & the shorter of \verb@%e@ (or \verb@%E@) and \verb@%f@ \\
3765: #\verb@%x@ or \verb@%X@ & hex \\
3766: #\verb@%o@ or \verb@%O@ & octal \\
3767: #\verb@%t@ & mantissa to base 10 \\
3768: #\verb@%l@ & mantissa to base of current logscale \\
3769: #\verb@%s@ & mantissa to base of current logscale; scientific power \\
3770: #\verb@%T@ & power to base 10 \\
3771: #\verb@%L@ & power to base of current logscale \\
3772: #\verb@%S@ & scientific power \\
3773: #\verb@%c@ & character replacement for scientific power \\
3774: #\verb@%P@ & multiple of pi \\
3775: %c l .
3776: %Format@Explanation
3777: %_
3778: %%f@floating point notation
3779: %%e or %E@exponential notation; an "e" or "E" before the power
3780: %%g or %G@the shorter of %e (or %E) and %f
3781: %%x or %X@hex
3782: %%o or %O@octal
3783: %%t@mantissa to base 10
3784: %%l@mantissa to base of current logscale
3785: %%s@mantissa to base of current logscale; scientific power
3786: %%T@power to base 10
3787: %%L@power to base of current logscale
3788: %%S@scientific power
3789: %%c@character replacement for scientific power
3790: %%P@multiple of pi
3791: %_
3792: @end table
3793:
3794: A 'scientific' power is one such that the exponent is a multiple of three.
3795: Character replacement of scientific powers (`"%c"`) has been implemented
3796: for powers in the range -18 to +18. For numbers outside of this range the
3797: format reverts to exponential.
3798:
3799: Other acceptable modifiers (which come after the "%" but before the format
3800: specifier) are "-", which left-justifies the number; "+", which forces all
3801: numbers to be explicitly signed; "#", which places a decimal point after
3802: floats that have only zeroes following the decimal point; a positive integer,
3803: which defines the field width; "0" (the digit, not the letter) immediately
3804: preceding the field width, which indicates that leading zeroes are to be used
3805: instead of leading blanks; and a decimal point followed by a non-negative
3806: integer, which defines the precision (the minimum number of digits of an
3807: integer, or the number of digits following the decimal point of a float).
3808:
3809: Some releases of 'printf' may not support all of these modifiers but may also
3810: support others; in case of doubt, check the appropriate documentation and
3811: then experiment.
3812:
3813: Examples:
3814: set format y "%t"; set ytics (5,10) # "5.0" and "1.0"
3815: set format y "%s"; set ytics (500,1000) # "500" and "1.0"
3816: set format y "+-12.3f"; set ytics(12345) # "+12345.000 "
3817: set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
3818: set format y "%s*10^{%S}"; set ytic(12345) # "12.345*10^{3}"
3819: set format y "%s %cg"; set ytic(12345) # "12.345 kg"
3820: set format y "%.0P pi"; set ytic(6.283185) # "2 pi"
3821: set format y "%.0P%%"; set ytic(50) # "50%"
3822:
3823: set log y 2; set format y '%l'; set ytics (1,2,3)
3824: #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)
3825:
3826: There are some problem cases that arise when numbers like 9.999 are printed
3827: with a format that requires both rounding and a power.
3828:
3829: If the data type for the axis is time/date, the format string must contain
3830: valid codes for the 'strftime' function (outside of `gnuplot`, type "man
3831: strftime"). See `set timefmt` for a list of the allowed input format codes.
3832: 4 time/date specifiers
3833: ?commands set format time/date_specifiers
3834: ?set format time/date_specifiers
3835: ?set time/date_specifiers
3836: ?time/date_specifiers
3837: In time/date mode, the acceptable formats are:
3838:
3839: @start table - first is interactive cleartext form
3840: Format Explanation
3841: %a abbreviated name of day of the week
3842: %A full name of day of the week
3843: %b or %h abbreviated name of the month
3844: %B full name of the month
3845: %d day of the month, 1--31
3846: %D shorthand for "%m/%d/%y"
3847: %H or %k hour, 0--24
3848: %I or %l hour, 0--12
3849: %j day of the year, 1--366
3850: %m month, 1--12
3851: %M minute, 0--60
3852: %p "am" or "pm"
3853: %r shorthand for "%I:%M:%S %p"
3854: %R shorthand for %H:%M"
3855: %S second, 0--60
3856: %T shorthand for "%H:%M:%S"
3857: %U week of the year (week starts on Sunday)
3858: %w day of the week, 0--6 (Sunday = 0)
3859: %W week of the year (week starts on Monday)
3860: %y year, 0-99
3861: %Y year, 4-digit
3862: #\begin{tabular}{|cl|} \hline
3863: #\multicolumn{2}{|c|}{Tic-mark label Date/Time Format Specifiers}\\
3864: #\hline \hline
3865: #Format & Explanation \\ \hline
3866: #\verb@%a@ & abbreviated name of day of the week \\
3867: #\verb@%A@ & full name of day of the week \\
3868: #\verb@%b@ or \verb@%h@ & abbreviated name of the month \\
3869: #\verb@%B@ & full name of the month \\
3870: #\verb@%d@ & day of the month, 1--31 \\
3871: #\verb@%D@ & shorthand for \verb@"%m/%d/%y"@ \\
3872: #\verb@%H@ or \verb@%k@ & hour, 0--24 \\
3873: #\verb@%I@ or \verb@%l@ & hour, 0--12 \\
3874: #\verb@%j@ & day of the year, 1--366 \\
3875: #\verb@%m@ & month, 1--12 \\
3876: #\verb@%M@ & minute, 0--60 \\
3877: #\verb@%p@ & "am" or "pm" \\
3878: #\verb@%r@ & shorthand for \verb@"%I:%M:%S %p"@ \\
3879: #\verb@%R@ & shorthand for \verb@%H:%M"@ \\
3880: #\verb@%S@ & second, 0--60 \\
3881: #\verb@%T@ & shorthand for \verb@"%H:%M:%S"@ \\
3882: #\verb@%U@ & week of the year (week starts on Sunday) \\
3883: #\verb@%w@ & day of the week, 0--6 (Sunday = 0) \\
3884: #\verb@%W@ & week of the year (week starts on Monday) \\
3885: #\verb@%y@ & year, 0-99 \\
3886: #\verb@%Y@ & year, 4-digit \\
3887: %c l .
3888: %Format@Explanation
3889: %_
3890: %%a@abbreviated name of day of the week
3891: %%A@full name of day of the week
3892: %%b or %h@abbreviated name of the month
3893: %%B@full name of the month
3894: %%d@day of the month, 1--31
3895: %%D@shorthand for "%m/%d/%y"
3896: %%H or %k@hour, 0--24
3897: %%I or %l@hour, 0--12
3898: %%j@day of the year, 1--366
3899: %%m@month, 1--12
3900: %%M@minute, 0--60
3901: %%p@"am" or "pm"
3902: %%r@shorthand for "%I:%M:%S %p"
3903: %%R@shorthand for %H:%M"
3904: %%S@second, 0--60
3905: %%T@shorthand for "%H:%M:%S"
3906: %%U@week of the year (week starts on Sunday)
3907: %%w@day of the week, 0--6 (Sunday = 0)
3908: %%W@week of the year (week starts on Monday)
3909: %%y@year, 0-99
3910: %%Y@year, 4-digit
3911: %_
3912: @end table
3913:
3914: Except for the non-numerical formats, these may be preceded by a "0" ("zero",
3915: not "oh") to pad the field length with leading zeroes, and a positive digit,
3916: to define the minimum field width (which will be overridden if the specified
3917: width is not large enough to contain the number). There is a 24-character
3918: limit to the length of the printed text; longer strings will be truncated.
3919:
3920: Examples:
3921:
3922: Suppose the text is "76/12/25 23:11:11". Then
3923: set format x # defaults to "12/25/76" \n "23:11"
3924: set format x "%A, %d %b %Y" # "Saturday, 25 Dec 1976"
3925: set format x "%r %d" # "11:11:11 pm 12/25/76"
3926:
3927: Suppose the text is "98/07/06 05:04:03". Then
3928: set format x "%1y/%2m/%3d %01H:%02M:%03S" # "98/ 7/ 6 5:04:003"
3929: 3 function style
3930: ?commands set function style
3931: ?commands show function style
3932: ?set function style
3933: ?show function style
3934: ?function style
3935: The `set function style` command changes the default plotting style for
3936: function plots.
3937:
3938: Syntax:
3939: set function style <style-choice>
3940: show function style
3941:
3942: See `set style` for the choices. If no choice is given, the choices are
3943: listed. `show function style` shows the current default function plotting
3944: style.
3945: 3 functions
3946: ?commands show functions
3947: ?show functions
3948: The `show functions` command lists all user-defined functions and their
3949: definitions.
3950:
3951: Syntax:
3952: show functions
3953:
3954: For information about the definition and usage of functions in `gnuplot`,
3955: please see `expressions`.
1.1.1.2 ! maekawa 3956: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/spline.html"> Splines as User Defined Functions.</a>
! 3957: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/airfoil.html">Use of functions and complex variables for airfoils </a>
1.1 maekawa 3958: 3 grid
3959: ?commands set grid
3960: ?commands set nogrid
3961: ?commands show grid
3962: ?set grid
3963: ?set nogrid
3964: ?show grid
3965: ?grid
3966: ?nogrid
3967: The `set grid` command allows grid lines to be drawn on the plot.
3968:
3969: Syntax:
3970: set grid {{no}{m}xtics} {{no}{m}ytics} {{no}{m}ztics}
3971: {{no}{m}x2tics} {{no}{m}y2tics}
3972: {polar {<angle>}}
3973: { {linestyle <major_linestyle>}
3974: | {linetype | lt <major_linetype>}
3975: {linewidth | lw <major_linewidth>}
3976: { , {linestyle | ls <minor_linestyle>}
3977: | {linetype | lt <minor_linetype>}
3978: {linewidth | lw <minor_linewidth>} } }
3979: set nogrid
3980: show grid
3981:
3982: The grid can be enabled and disabled for the major and/or minor tic
3983: marks on any axis, and the linetype and linewidth can be specified
3984: for major and minor grid lines, also via a predefined linestyle, as
3985: far as the active terminal driver supports this.
3986:
3987: Additionally, a polar grid can be selected for 2-d plots---circles are drawn
3988: to intersect the selected tics, and radial lines are drawn at definable
3989: intervals. (The interval is given in degrees or radians ,depending on the
3990: `set angles` setting.) Note that a polar grid is no longer automatically
3991: generated in polar mode.
3992:
3993: The pertinent tics must be enabled before `set grid` can draw them; `gnuplot`
3994: will quietly ignore instructions to draw grid lines at non-existent tics, but
3995: they will appear if the tics are subsequently enabled.
3996:
3997: If no linetype is specified for the minor gridlines, the same linetype as the
3998: major gridlines is used. The default polar angle is 30 degrees.
3999:
1.1.1.2 ! maekawa 4000: By default, grid lines are drawn with half the usual linewidth. The major and
! 4001: minor linewidth specifiers scale this default value; for example, `set grid
! 4002: lw .5` will draw grid lines with one quarter the usual linewidth.
! 4003:
1.1 maekawa 4004: Z grid lines are drawn on the back of the plot. This looks better if a
4005: partial box is drawn around the plot---see `set border`.
4006: 3 hidden3d
4007: ?commands set hidden3d
4008: ?commands set nohidden3d
4009: ?commands show hidden3d
4010: ?set hidden3d
4011: ?set nohidden3d
4012: ?show hidden3d
4013: ?hidden3d
4014: ?nohidden3d
4015: The `set hidden3d` command enables hidden line removal for surface plotting
4016: (see `splot`). Some optional features of the underlying algorithm can also
4017: be controlled using this command.
4018:
4019: Syntax:
4020: set hidden3d {defaults} |
4021: { {{offset <offset>} | {nooffset}}
4022: {trianglepattern <bitpattern>}
4023: {{undefined <level>} | {noundefined}}
4024: {{no}altdiagonal}
4025: {{no}bentover} }
4026: set nohidden3d
4027: show hidden3d
4028:
4029: In contrast to the usual display in gnuplot, hidden line removal actually
4030: treats the given function or data grids as real surfaces that can't be seen
4031: through, so parts behind the surface will be hidden by it. For this to be
4032: possible, the surface needs to have 'grid structure' (see `splot datafile`
4033: about this), and it has to be drawn `with lines` or `with linespoints`.
4034:
4035: When `hidden3d` is set, both the hidden portion of the surface and possibly
4036: its contours drawn on the base (see `set contour`) as well as the grid will
4037: be hidden. Each surface has its hidden parts removed with respect to itself
4038: and to other surfaces, if more than one surface is plotted. Contours drawn
4039: on the surface (`set contour surface`) don't work. Labels and arrows are
4040: always visible and are unaffected. The key is also never hidden by the
4041: surface.
4042:
4043: Functions are evaluated at isoline intersections. The algorithm interpolates
4044: linearly between function points or data points when determining the visible
4045: line segments. This means that the appearance of a function may be different
4046: when plotted with `hidden3d` than when plotted with `nohidden3d` because in
4047: the latter case functions are evaluated at each sample. Please see `set
4048: samples` and `set isosamples` for discussion of the difference.
4049:
4050: The algorithm used to remove the hidden parts of the surfaces has some
4051: additional features controllable by this command. Specifying `defaults` will
4052: set them all to their default settings, as detailed below. If `defaults` is
4053: not given, only explicitly specified options will be influenced: all others
4054: will keep their previous values, so you can turn on/off hidden line removal
4055: via `set {no}hidden3d`, without modifying the set of options you chose.
4056:
4057: The first option, `offset`, influences the linestyle used for lines on the
4058: 'back' side. Normally, they are drawn in a linestyle one index number higher
4059: than the one used for the front, to make the two sides of the surface
4060: distinguishable. You can specify a different line style offset to add
4061: instead of the default 1, by `offset <offset>`. Option `nooffset` stands for
4062: `offset 0`, making the two sides of the surface use the same linestyle.
4063:
4064: Next comes the option `trianglepattern <bitpattern>`. <bitpattern> must be
4065: a number between 0 and 7, interpreted as a bit pattern. Each bit determines
4066: the visibility of one edge of the triangles each surface is split up into.
4067: Bit 0 is for the 'horizontal' edges of the grid, Bit 1 for the 'vertical'
4068: ones, and Bit 2 for the diagonals that split each cell of the original grid
4069: into two triangles. The default pattern is 3, making all horizontal and
4070: vertical lines visible, but not the diagonals. You may want to choose 7 to
4071: see those diagonals as well.
4072:
4073: The `undefined <level>` option lets you decide what the algorithm is to do
4074: with data points that are undefined (missing data, or undefined function
4075: values), or exceed the given x-, y- or z-ranges. Such points can either be
4076: plotted nevertheless, or taken out of the input data set. All surface
4077: elements touching a point that is taken out will be taken out as well, thus
4078: creating a hole in the surface. If <level> = 3, equivalent to option
4079: `noundefined`, no points will be thrown away at all. This may produce all
4080: kinds of problems elsewhere, so you should avoid this. <level> = 2 will
4081: throw away undefined points, but keep the out-of-range ones. <level> = 1,
4082: the default, will get rid of out-of-range points as well.
4083:
4084: By specifying `noaltdiagonal`, you can override the default handling of a
4085: special case can occur if `undefined` is active (i.e. <level> is not 3).
4086: Each cell of the grid-structured input surface will be divided in two
4087: triangles along one of its diagonals. Normally, all these diagonals have
4088: the same orientation relative to the grid. If exactly one of the four cell
4089: corners is excluded by the `undefined` handler, and this is on the usual
4090: diagonal, both triangles will be excluded. However if the default setting
4091: of `altdiagonal` is active, the other diagonal will be chosen for this cell
4092: instead, minimizing the size of the hole in the surface.
4093:
4094: The `bentover` option controls what happens to another special case, this
4095: time in conjunction with the `trianglepattern`. For rather crumply surfaces,
4096: it can happen that the two triangles a surface cell is divided into are seen
4097: from opposite sides (i.e. the original quadrangle is 'bent over'), as
4098: illustrated in the following ASCII art:
4099:
4100: C----B
4101: original quadrangle: A--B displayed quadrangle: |\ |
4102: ("set view 0,0") | /| ("set view 75,75" perhaps) | \ |
4103: |/ | | \ |
4104: C--D | \|
4105: A D
4106:
4107: If the diagonal edges of the surface cells aren't generally made visible by
4108: bit 2 of the <bitpattern> there, the edge CB above wouldn't be drawn at all,
4109: normally, making the resulting display hard to understand. Therefore, the
4110: default option of `bentover` will turn it visible in this case. If you don't
4111: want that, you may choose `nobentover` instead.
1.1.1.2 ! maekawa 4112: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/hidden.html"> Hidden Line Removal Demo</a> and
! 4113: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/singulr.html"> Complex Hidden Line Demo. </a>
1.1 maekawa 4114: 3 isosamples
4115: ?commands set isosamples
4116: ?commands show isosamples
4117: ?set isosamples
4118: ?show isosamples
4119: ?isosamples
4120: The isoline density (grid) for plotting functions as surfaces may be changed
4121: by the `set isosamples` command.
4122:
4123: Syntax:
4124: set isosamples <iso_1> {,<iso_2>}
4125: show isosamples
4126:
4127: Each function surface plot will have <iso_1> iso-u lines and <iso_2> iso-v
4128: lines. If you only specify <iso_1>, <iso_2> will be set to the same value
4129: as <iso_1>. By default, sampling is set to 10 isolines per u or v axis.
4130: A higher sampling rate will produce more accurate plots, but will take longer.
4131: These parameters have no effect on data file plotting.
4132:
4133: An isoline is a curve parameterized by one of the surface parameters while
4134: the other surface parameter is fixed. Isolines provide a simple means to
4135: display a surface. By fixing the u parameter of surface s(u,v), the iso-u
4136: lines of the form c(v) = s(u0,v) are produced, and by fixing the v parameter,
4137: the iso-v lines of the form c(u) = s(u,v0) are produced.
4138:
4139: When a function surface plot is being done without the removal of hidden
4140: lines, `set samples` controls the number of points sampled along each
4141: isoline; see `set samples` and `set hidden3d`. The contour algorithm
4142: assumes that a function sample occurs at each isoline intersection, so
4143: change in `samples` as well as `isosamples` may be desired when changing
4144: the resolution of a function surface/contour.
4145: 3 key
4146: ?commands set key
4147: ?commands set nokey
4148: ?commands show key
4149: ?set key
4150: ?set nokey
4151: ?show key
4152: ?key
4153: ?nokey
4154: ?legend
4155: The `set key` enables a key (or legend) describing plots on a plot.
4156:
4157: The contents of the key, i.e., the names given to each plotted data set and
4158: function and samples of the lines and/or symbols used to represent them, are
4159: determined by the `title` and `with` options of the {`s`}`plot` command.
4160: Please see `plot title` and `plot with` for more information.
4161:
4162: Syntax:
4163: set key { left | right | top | bottom | outside | below
4164: | <position>}
4165: {Left | Right} {{no}reverse}
4166: {samplen <sample_length>} {spacing <vertical_spacing>}
4167: {width <width_increment>}
4168: {title "<text>"}
4169: {{no}box { {linestyle | ls <line_style>}
4170: | {linetype | lt <line_type>}
4171: {linewidth | lw <line_width>}}}
4172: set nokey
4173: show key
4174:
4175: By default the key is placed in the upper right corner of the graph. The
4176: keywords `left`, `right`, `top`, `bottom`, `outside` and `below` may be used
4177: to place the key in the other corners inside the graph or to the right
4178: (outside) or below the graph. They may be given alone or combined.
4179:
4180: Justification of the labels within the key is controlled by `Left` or `Right`
4181: (default is `Right`). The text and sample can be reversed (`reverse`) and a
4182: box can be drawn around the key (`box {...}`) in a specified `linetype`
4183: and `linewidth`, or a user-defined `linestyle`. Note that not all
4184: terminal drivers support linewidth selection, though.
4185:
4186: The length of the sample line can be controlled by `samplen`. The sample
4187: length is computed as the sum of the tic length and <sample_length> times the
4188: character width. `samplen` also affects the positions of point samples in
4189: the key since these are drawn at the midpoint of the sample line, even if it
4190: is not drawn. <sample_length> must be an integer.
4191:
4192: The vertical spacing between lines is controlled by `spacing`. The spacing
4193: is set equal to the product of the pointsize, the vertical tic size, and
4194: <vertical_spacing>. The program will guarantee that the vertical spacing is
4195: no smaller than the character height.
4196:
4197: The <width_increment> is a number of character widths to be added to or
4198: subtracted from the length of the string. This is useful only when you are
4199: putting a box around the key and you are using control characters in the text.
4200: `gnuplot` simply counts the number of characters in the string when computing
4201: the box width; this allows you to correct it.
4202:
4203: A title can be put on the key (`title "<text>"`)---see also `syntax` for the
4204: distinction between text in single- or double-quotes. The key title uses the
4205: same justification as do the plot titles.
4206:
4207: The defaults for `set key` are `right`, `top`, `Right`, `noreverse`, `samplen
4208: 4`, `spacing 1.25`, `title ""`, and `nobox`. The default <linetype> is the
4209: same as that used for the plot borders. Entering `set key` with no options
4210: returns the key to its default configuration.
4211:
4212: The <position> can be a simple x,y,z as in previous versions, but these can
4213: be preceded by one of four keywords (`first`, `second`, `graph`, `screen`)
4214: which selects the coordinate system in which the position is specified. See
4215: `coordinates` for more details.
4216:
4217: The key is drawn as a sequence of lines, with one plot described on each
4218: line. On the right-hand side (or the left-hand side, if `reverse` is
4219: selected) of each line is a representation that attempts to mimic the way the
4220: curve is plotted. On the other side of each line is the text description
4221: (the line title), obtained from the `plot` command. The lines are vertically
4222: arranged so that an imaginary straight line divides the left- and right-hand
4223: sides of the key. It is the coordinates of the top of this line that are
4224: specified with the `set key` command. In a `plot`, only the x and y
4225: coordinates are used to specify the line position. For a `splot`, x, y and
4226: z are all used as a 3-d location mapped using the same mapping as the graph
4227: itself to form the required 2-d screen position of the imaginary line.
4228:
4229: Some or all of the key may be outside of the graph boundary, although this
4230: may interfere with other labels and may cause an error on some devices. If
4231: you use the keywords `outside` or `below`, `gnuplot` makes space for the keys
4232: and the graph becomes smaller. Putting keys outside to the right, they
4233: occupy as few columns as possible, and putting them below, as many columns as
4234: possible (depending of the length of the labels), thus stealing as little
4235: space from the graph as possible.
4236:
4237: When using the TeX or PostScript drivers, or similar drivers where formatting
4238: information is embedded in the string, `gnuplot` is unable to calculate
4239: correctly the width of the string for key positioning. If the key is to be
4240: positioned at the left, it may be convenient to use the combination `set key
4241: left Left reverse`. The box and gap in the grid will be the width of the
4242: literal string.
4243:
4244: If `splot` is being used to draw contours, the contour labels will be listed
4245: in the key. If the alignment of these labels is poor or a different number
4246: of decimal places is desired, the label format can be specified. See `set
4247: clabel` for details.
4248:
4249: Examples:
4250:
4251: This places the key at the default location:
4252: set key
4253:
4254: This disables the key:
4255: set nokey
4256:
4257: This places a key at coordinates 2,3.5,2 in the default (first) coordinate
4258: system:
4259: set key 2,3.5,2
4260:
4261: This places the key below the graph:
4262: set key below
4263:
4264: This places the key in the bottom left corner, left-justifies the text,
4265: gives it a title, and draws a box around it in linetype 3:
4266: set key left bottom Left title 'Legend' box 3
4267: 3 label
4268: ?commands set label
4269: ?commands set nolabel
4270: ?commands show label
4271: ?set label
4272: ?set nolabel
4273: ?show label
4274: ?label
4275: ?nolabel
4276: Arbitrary labels can be placed on the plot using the `set label` command.
4277:
4278: Syntax:
4279: set label {<tag>} {"<label_text>"} {at <position>}
4280: {<justification>} {{no}rotate} {font "<name><,size>"}
4281: set nolabel {<tag>}
4282: show label
4283:
4284: The <position> is specified by either x,y or x,y,z, and may be preceded by
4285: `first`, `second`, `graph`, or `screen` to select the coordinate system.
4286: See `coordinates` for details.
4287:
4288: The tag is an integer that is used to identify the label. If no <tag> is
4289: given, the lowest unused tag value is assigned automatically. The tag can be
4290: used to delete or modify a specific label. To change any attribute of an
4291: existing label, use the `set label` command with the appropriate tag, and
4292: specify the parts of the label to be changed.
4293:
4294: By default, the text is placed flush left against the point x,y,z. To adjust
4295: the way the label is positioned with respect to the point x,y,z, add the
4296: parameter <justification>, which may be `left`, `right` or `center`,
4297: indicating that the point is to be at the left, right or center of the text.
4298: Labels outside the plotted boundaries are permitted but may interfere with
4299: axis labels or other text.
4300:
4301: If `rotate` is given, the label is written vertically (if the terminal can do
4302: so, of course).
4303:
4304: If one (or more) axis is timeseries, the appropriate coordinate should be
4305: given as a quoted time string according to the `timefmt` format string. See
4306: `set xdata` and `set timefmt`.
4307:
4308: The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
4309: a newline.
4310:
4311: Examples:
4312:
4313: To set a label at (1,2) to "y=x", use:
4314: set label "y=x" at 1,2
4315:
4316: To set a Sigma of size 24, from the Symbol font set, at the center of
4317: the graph, use:
4318: set label "S" at graph 0.5,0.5 center font "Symbol,24"
4319:
4320: To set a label "y=x^2" with the right of the text at (2,3,4), and tag the
4321: label as number 3, use:
4322: set label 3 "y=x^2" at 2,3,4 right
4323:
4324: To change the preceding label to center justification, use:
4325: set label 3 center
4326:
4327: To delete label number 2, use:
4328: set nolabel 2
4329:
4330: To delete all labels, use:
4331: set nolabel
4332:
4333: To show all labels (in tag order), use:
4334: show label
4335:
4336: To set a label on a graph with a timeseries on the x axis, use, for example:
4337: set timefmt "%d/%m/%y,%H:%M"
4338: set label "Harvest" at "25/8/93",1
4339: 3 linestyle
4340: ?commands set linestyle
4341: ?commands set nolinestyle
4342: ?commands show linestyle
4343: ?set linestyle
4344: ?set nolinestyle
4345: ?show linestyle
4346: ?linestyle
4347: Each terminal has a default set of line and point types, which can be seen
4348: by using the command `test`. `set linestyle` defines a set of line types
4349: and widths and point types and sizes so that you can refer to them later by
4350: an index instead of repeating all the information at each invocation.
4351:
4352: Syntax:
4353: set linestyle <index> {linetype | lt <line_type>}
4354: {linewidth | lw <line_width>}
4355: {pointtype | pt <point_type>}
4356: {pointsize | ps <point_size>}
4357: set nolinestyle
4358: show linestyle
4359:
4360: The line and point types are taken from the default types for the terminal
4361: currently in use. The line width and point size are multipliers for the
4362: default width and size (but note that <point_size> here is unaffected by
4363: the multiplier given on 'set pointsize').
4364:
4365: The defaults for the line and point types is the index. The defaults for
4366: the width and size are both unity.
4367:
4368: Linestyles created by this mechanism do not replace the default styles;
4369: both may be used.
4370:
4371: Not all terminals support the `linewidth` and `pointsize` features; if
4372: not supported, the option will be ignored.
4373:
4374: Note that this feature is not completely implemented; linestyles defined by
4375: this mechanism may be used with 'plot', 'splot', 'replot', and 'set arrow',
4376: but not by other commands that allow the default index to be used, such as
4377: 'set grid'.
4378:
4379: Example:
4380: Suppose that the default lines for indices 1, 2, and 3 are red, green, and
4381: blue, respectively, and the default point shapes for the same indices are a
4382: square, a cross, and a triangle, respectively. Then
4383:
4384: set linestyle 1 lt 2 lw 2 pt 3 ps 0.5
4385:
4386: defines a new linestyle that is green and twice the default width and a new
4387: pointstyle that is a half-sized triangle. The commands
4388:
4389: set function style lines
4390: plot f(x) lt 3, g(x) ls 1
4391:
4392: will create a plot of f(x) using the default blue line and a plot of g(x)
4393: using the user-defined wide green line. Similarly the commands
4394:
4395: set function style linespoints
4396: plot p(x) lt 1 pt 3, q(x) ls 1
4397:
4398: will create a plot of f(x) using the default triangles connected by a red
4399: line and q(x) using small triangles connected by a green line.
4400: 3 lmargin
4401: ?commands set lmargin
4402: ?set lmargin
4403: ?lmargin
4404: The command `set lmargin` sets the size of the left margin. Please see
4405: `set margin` for details.
4406: 3 locale
4407: ?commands set locale
4408: ?commands show logscale
4409: ?set locale
4410: ?show logscale
4411: ?locale
4412: The `locale` setting determines the language with which `{x,y,z}{d,m}tics`
4413: will write the days and months.
4414:
4415: Syntax:
4416: set locale {"<locale>"}
4417:
4418: <locale> may be any language designation acceptable to your installation.
4419: See your system documentation for the available options. The default value
4420: is determined from the LANG environment variable.
4421: 3 logscale
4422: ?commands set logscale
4423: ?commands set nologscale
4424: ?commands show logscale
4425: ?set logscale
4426: ?set nologscale
4427: ?show logscale
4428: ?logscale
4429: ?nologscale
4430: Log scaling may be set on the x, y, z, x2 and/or y2 axes.
4431:
4432: Syntax:
4433: set logscale <axes> <base>
4434: set nologscale <axes>
4435: show logscale
4436:
4437: where <axes> may be any combinations of `x`, `y`, and `z`, in any order, or
4438: `x2` or `y2` and where <base> is the base of the log scaling. If <base> is
4439: not given, then 10 is assumed. If <axes> is not given, then all axes are
4440: assumed. `set nologscale` turns off log scaling for the specified axes.
4441:
4442: Examples:
4443:
4444: To enable log scaling in both x and z axes:
4445: set logscale xz
4446:
4447: To enable scaling log base 2 of the y axis:
4448: set logscale y 2
4449:
4450: To disable z axis log scaling:
4451: set nologscale z
4452: 3 mapping
4453: ?commands set mapping
4454: ?commands show mapping
4455: ?set mapping
4456: ?show mapping
4457: ?mapping
4458: If data are provided to `splot` in spherical or cylindrical coordinates,
4459: the `set mapping` command should be used to instruct `gnuplot` how to
4460: interpret them.
4461:
4462: Syntax:
4463: set mapping {cartesian | spherical | cylindrical}
4464:
4465: A cartesian coordinate system is used by default.
4466:
4467: For a spherical coordinate system, the data occupy two or three columns (or
4468: `using` entries). The first two are interpreted as the polar and azimuthal
4469: angles theta and phi (in the units specified by `set angles`). The radius r
4470: is taken from the third column if there is one, or is set to unity if there
4471: is no third column. The mapping is:
4472:
4473: x = r * cos(theta) * cos(phi)
4474: y = r * sin(theta) * cos(phi)
4475: z = r * sin(phi)
4476:
4477: Note that this is a "geographic" spherical system, rather than a "polar" one.
4478:
4479: For a cylindrical coordinate system, the data again occupy two or three
4480: columns. The first two are interpreted as theta (in the units specified by
4481: `set angles`) and z. The radius is either taken from the third column or set
4482: to unity, as in the spherical case. The mapping is:
4483:
4484: x = r * cos(theta)
4485: y = r * sin(theta)
4486: z = z
4487:
4488: The effects of `mapping` can be duplicated with the `using` filter on the
4489: `splot` command, but `mapping` may be more convenient if many data files are
4490: to be processed. However even if `mapping` is used, `using` may still be
4491: necessary if the data in the file are not in the required order.
4492:
4493: `mapping` has no effect on `plot`.
1.1.1.2 ! maekawa 4494: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/world.html">Mapping Demos.</a>
1.1 maekawa 4495: 3 margin
4496: ?commands set margin
4497: ?commands show margin
4498: ?set margin
4499: ?show margin
4500: ?margin
1.1.1.2 ! maekawa 4501: The computed margins can be overridden by the `set margin` commands. `show
! 4502: margin` shows the current settings.
1.1 maekawa 4503:
4504: Syntax:
4505: set bmargin {<margin>}
4506: set lmargin {<margin>}
4507: set rmargin {<margin>}
4508: set tmargin {<margin>}
4509: show margin
4510:
4511: The units of <margin> are character heights or widths, as appropriate. A
4512: positive value defines the absolute size of the margin. A negative value
4513: (or none) causes `gnuplot` to revert to the computed value.
1.1.1.2 ! maekawa 4514:
! 4515: Normally the margins of a plot are automatically calculated based on tics,
! 4516: tic labels, axis labels, the plot title, the timestamp and the size of the
! 4517: key if it is outside the borders. If, however, tics are attached to the
! 4518: axes (`set xtics axis`, for example), neither the tics themselves nor their
! 4519: labels will be included in either the margin calculation or the calculation
! 4520: of the positions of other text to be written in the margin. This can lead
! 4521: to tic labels overwriting other text if the axis is very close to the border.
1.1 maekawa 4522: 3 missing
4523: ?commands set missing
4524: ?set missing
4525: ?missing
4526: The `set missing` command allows you to tell `gnuplot` what character is
4527: used in a data file to denote missing data.
4528:
4529: Syntax:
4530: set missing {"<character>"}
4531: show missing
4532:
4533: Example:
4534: set missing "?"
4535:
4536: would mean that, when plotting a file containing
4537:
4538: 1 1
4539: 2 ?
4540: 3 2
4541:
4542: the middle line would be ignored.
4543:
4544: There is no default character for `missing`.
4545: 3 multiplot
4546: ?commands set multiplot
4547: ?commands set nomultiplot
4548: ?set multiplot
4549: ?set nomultiplot
4550: ?multiplot
4551: ?nomultiplot
4552: The command `set multiplot` places `gnuplot` in the multiplot mode, in which
4553: several plots are placed on the same page, window, or screen.
4554:
4555: Syntax:
4556: set multiplot
4557: set nomultiplot
4558:
4559: For some terminals, no plot is displayed until the command `set nomultiplot`
4560: is given, which causes the entire page to be drawn and then returns `gnuplot`
4561: to its normal single-plot mode. For other terminals, each separate `plot`
4562: command produces a plot, but the screen may not be cleared between plots.
4563:
4564: Any labels or arrows that have been defined will be drawn for each plot
4565: according to the current size and origin (unless their coordinates are
4566: defined in the `screen` system). Just about everything else that can be
4567: `set` is applied to each plot, too. If you want something to appear only
4568: once on the page, for instance a single time stamp, you'll need to put a `set
4569: time`/`set notime` pair around one of the `plot`, `splot` or `replot`
4570: commands within the `set multiplot`/`set nomultiplot` block.
4571:
4572: The commands `set origin` and `set size` must be used to correctly position
4573: each plot; see `set origin` and `set size` for details of their usage.
4574:
4575: Example:
4576: set size 0.7,0.7
4577: set origin 0.1,0.1
4578: set multiplot
4579: set size 0.4,0.4
4580: set origin 0.1,0.1
4581: plot sin(x)
4582: set size 0.2,0.2
4583: set origin 0.5,0.5
4584: plot cos(x)
4585: set nomultiplot
4586:
4587: displays a plot of cos(x) stacked above a plot of sin(x). Note the initial
4588: `set size` and `set origin`. While these are not always required, their
4589: inclusion is recommended. Some terminal drivers require that bounding box
4590: information be available before any plots can be made, and the form given
4591: above guarantees that the bounding box will include the entire plot array
4592: rather than just the bounding box of the first plot.
4593:
4594: `set size` and `set origin` refer to the entire plotting area used for each
4595: plot. If you want to have the axes themselves line up, you can guarantee
4596: that the margins are the same size with the `set margin` commands. See
4597: `set margin` for their use. Note that the margin settings are absolute,
4598: in character units, so the appearance of the graph in the remaining space
4599: will depend on the screen size of the display device, e.g., perhaps quite
4600: different on a video display and a printer.
1.1.1.2 ! maekawa 4601: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/multiplt.html"> See demo. </a>
1.1 maekawa 4602: 3 mx2tics
4603: ?commands set mx2tics
4604: ?commands set nomx2tics
4605: ?commands show mx2tics
4606: ?set mx2tics
4607: ?set nomx2tics
4608: ?show mx2tics
4609: ?mx2tics
4610: ?nomx2tics
4611: Minor tic marks along the x2 (top) axis are controlled by `set mx2tics`.
4612: Please see `set mxtics`.
4613: 3 mxtics
4614: ?commands set mxtics
4615: ?commands set nomxtics
4616: ?commands show mxtics
4617: ?set mxtics
4618: ?set nomxtics
4619: ?show mxtics
4620: ?mxtics
4621: ?nomxtics
4622: Minor tic marks along the x axis are controlled by `set mxtics`. They can be
4623: turned off with `set nomxtics`. Similar commands control minor tics along
4624: the other axes.
4625:
4626: Syntax:
4627: set mxtics {<freq> | default}
4628: set nomxtics
4629: show mxtics
4630:
4631: The same syntax applies to `mytics`, `mztics`, `mx2tics` and `my2tics`.
4632:
4633: <freq> is the number of sub-intervals (NOT the number of minor tics) between
4634: major tics (ten is the default for a linear axis, so there are nine minor
4635: tics between major tics). Selecting `default` will return the number of minor
4636: ticks to its default value.
4637:
4638: If the axis is logarithmic, the number of sub-intervals will be set to a
4639: reasonable number by default (based upon the length of a decade). This will
4640: be overridden if <freq> is given. However the usual minor tics (2, 3, ...,
4641: 8, 9 between 1 and 10, for example) are obtained by setting <freq> to 10,
4642: even though there are but nine sub-intervals.
4643:
4644: Minor tics can be used only with uniformly spaced major tics. Since major
4645: tics can be placed arbitrarily by `set {x|x2|y|y2|z}tics`, minor tics cannot
4646: be used if major tics are explicitly `set`.
4647:
4648: By default, minor tics are off for linear axes and on for logarithmic axes.
4649: They inherit the settings for `axis|border` and `{no}mirror` specified for
4650: the major tics. Please see `set xtics` for information about these.
4651: 3 my2tics
4652: ?commands set my2tics
4653: ?commands set nomy2tics
4654: ?commands show my2tics
4655: ?set my2tics
4656: ?set nomy2tics
4657: ?show my2tics
4658: ?my2tics
4659: ?nomy2tics
4660: Minor tic marks along the y2 (right-hand) axis are controlled by `set
4661: my2tics`. Please see `set mxtics`.
4662: 3 mytics
4663: ?commands set mytics
4664: ?commands set nomytics
4665: ?commands show mytics
4666: ?set mytics
4667: ?set nomytics
4668: ?show mytics
4669: ?mytics
4670: ?nomytics
4671: Minor tic marks along the y axis are controlled by `set mytics`. Please
4672: see `set mxtics`.
4673: 3 mztics
4674: ?commands set mztics
4675: ?commands set nomztics
4676: ?commands show mztics
4677: ?set mztics
4678: ?set nomztics
4679: ?show mztics
4680: ?mztics
4681: ?nomztics
4682: Minor tic marks along the z axis are controlled by `set mztics`. Please
4683: see `set mxtics`.
4684: 3 offsets
4685: ?commands set offsets
4686: ?commands set nooffsets
4687: ?commands show offsets
4688: ?set offsets
4689: ?set nooffsets
4690: ?show offsets
4691: ?offsets
4692: ?nooffsets
4693: Offsets provide a mechanism to put a boundary around the data inside of an
4694: autoscaled graph.
4695:
4696: Syntax:
4697: set offsets <left>, <right>, <top>, <bottom>
4698: set nooffsets
4699: show offsets
4700:
4701: Each offset may be a constant or an expression. Each defaults to 0. Left
4702: and right offsets are given in units of the x axis, top and bottom offsets in
4703: units of the y axis. A positive offset expands the graph in the specified
4704: direction, e.g., a positive bottom offset makes ymin more negative. Negative
4705: offsets, while permitted, can have unexpected interactions with autoscaling
4706: and clipping.
4707:
4708: Offsets are ignored in `splot`s.
4709:
4710: Example:
4711: set offsets 0, 0, 2, 2
4712: plot sin(x)
4713:
4714: This graph of sin(x) will have a y range [-3:3] because the function
4715: will be autoscaled to [-1:1] and the vertical offsets are each two.
4716: 3 origin
4717: ?commands set origin
4718: ?commands show origin
4719: ?set origin
4720: ?show origin
4721: ?origin
4722: The `set origin` command is used to specify the origin of a plotting surface
4723: (i.e., the graph and its margins) on the screen. The coordinates are given
4724: in the `screen` coordinate system (see `coordinates` for information about
4725: this system).
4726:
4727: Syntax:
4728: set origin <x-origin>,<y-origin>
4729: 3 output
4730: ?commands set output
4731: ?commands show output
4732: ?set output
4733: ?show output
4734: ?output
4735: By default, screens are displayed to the standard output. The `set output`
4736: command redirects the display to the specified file or device.
4737:
4738: Syntax:
4739: set output {"<filename>"}
4740: show output
4741:
4742: The filename must be enclosed in quotes. If the filename is omitted, any
4743: output file opened by a previous invocation of `set output` will be closed
4744: and new output will be sent to STDOUT. (If you give the command `set output
4745: "STDOUT"`, your output may be sent to a file named "STDOUT"! ["May be", not
4746: "will be", because some terminals, like `x11`, ignore `set output`.])
4747:
4748: MSDOS users should note that the \ character has special significance in
4749: double-quoted strings, so single-quotes should be used for filenames in
4750: different directories.
4751:
4752: When both `set terminal` and `set output` are used together, it is safest to
4753: give `set terminal` first, because some terminals set a flag which is needed
4754: in some operating systems. This would be the case, for example, if the
4755: operating system needs to know whether or not a file is to be formatted in
4756: order to open it properly.
4757:
4758: On machines with popen functions (Unix), output can be piped through a shell
4759: command if the first non-whitespace character of the filename is '|'.
4760: For instance,
4761:
4762: set output "|lpr -Plaser filename"
4763: set output "|lp -dlaser filename"
4764:
4765: On MSDOS machines, `set output "PRN"` will direct the output to the default
4766: printer. On VMS, output can be sent directly to any spooled device. It is
4767: also possible to send the output to DECnet transparent tasks, which allows
4768: some flexibility.
4769: 3 parametric
4770: ?commands set parametric
4771: ?commands set noparametric
4772: ?commands show parametric
4773: ?set parametric
4774: ?set noparametric
4775: ?show parametric
4776: ?parametric
4777: ?noparametric
4778: The `set parametric` command changes the meaning of `plot` (`splot`) from
4779: normal functions to parametric functions. The command `set noparametric`
4780: restores the plotting style to normal, single-valued expression plotting.
4781:
4782: Syntax:
4783: set parametric
4784: set noparametric
4785: show parametric
4786:
4787: For 2-d plotting, a parametric function is determined by a pair of parametric
4788: functions operating on a parameter. An example of a 2-d parametric function
4789: would be `plot sin(t),cos(t)`, which draws a circle (if the aspect ratio is
4790: set correctly---see `set size`). `gnuplot` will display an error message if
4791: both functions are not provided for a parametric `plot`.
4792:
4793: For 3-d plotting, the surface is described as x=f(u,v), y=g(u,v), z=h(u,v).
4794: Therefore a triplet of functions is required. An example of a 3-d parametric
4795: function would be `cos(u)*cos(v),cos(u)*sin(v),sin(u)`, which draws a sphere.
4796: `gnuplot` will display an error message if all three functions are not
4797: provided for a parametric `splot`.
4798:
4799: The total set of possible plots is a superset of the simple f(x) style plots,
4800: since the two functions can describe the x and y values to be computed
4801: separately. In fact, plots of the type t,f(t) are equivalent to those
4802: produced with f(x) because the x values are computed using the identity
4803: function. Similarly, 3-d plots of the type u,v,f(u,v) are equivalent to
4804: f(x,y).
4805:
4806: Note that the order the parametric functions are specified is xfunction,
4807: yfunction (and zfunction) and that each operates over the common parametric
4808: domain.
4809:
4810: Also, the `set parametric` function implies a new range of values. Whereas
4811: the normal f(x) and f(x,y) style plotting assume an xrange and yrange (and
4812: zrange), the parametric mode additionally specifies a trange, urange, and
4813: vrange. These ranges may be set directly with `set trange`, `set urange`,
4814: and `set vrange`, or by specifying the range on the `plot` or `splot`
4815: commands. Currently the default range for these parametric variables is
4816: [-5:5]. Setting the ranges to something more meaningful is expected.
4817: 3 pointsize
4818: ?commands set pointsize
4819: ?commands show pointsize
4820: ?set pointsize
4821: ?show pointsize
4822: ?pointsize
4823: The `set pointsize` command scales the size of the points used in plots.
4824:
4825: Syntax:
4826: set pointsize <multiplier>
4827: show pointsize
4828:
4829: The default is a multiplier of 1.0. Larger pointsizes may be useful to
4830: make points more visible in bitmapped graphics.
4831:
4832: The pointsize of a single plot may be changed on the `plot` command. See
4833: `plot with` for details.
4834:
4835: Please note that the pointsize setting is not supported by all terminal
4836: types.
4837: 3 polar
4838: ?commands set polar
4839: ?commands set nopolar
4840: ?commands show polar
4841: ?set polar
4842: ?set nopolar
4843: ?show polar
4844: ?polar
4845: ?nopolar
4846: The `set polar` command changes the meaning of the plot from rectangular
4847: coordinates to polar coordinates.
4848:
4849: Syntax:
4850: set polar
4851: set nopolar
4852: show polar
4853:
4854: There have been changes made to polar mode in version 3.7, so that scripts
4855: for `gnuplot` versions 3.5 and earlier will require modification. The main
4856: change is that the dummy variable t is used for the angle so that the x and
4857: y ranges can be controlled independently. Other changes are:
4858: 1) tics are no longer put along the zero axes automatically
4859: ---use `set xtics axis nomirror`; `set ytics axis nomirror`;
4860: 2) the grid, if selected, is not automatically polar
4861: ---use `set grid polar`;
4862: 3) the grid is not labelled with angles
4863: ---use `set label` as necessary.
4864:
4865: In polar coordinates, the dummy variable (t) is an angle. The default range
4866: of t is [0:2*pi], or, if degree units have been selected, to [0:360] (see
4867: `set angles`).
4868:
4869: The command `set nopolar` changes the meaning of the plot back to the default
4870: rectangular coordinate system.
4871:
4872: The `set polar` command is not supported for `splot`s. See the `set mapping`
4873: command for similar functionality for `splot`s.
4874:
4875: While in polar coordinates the meaning of an expression in t is really
4876: r = f(t), where t is an angle of rotation. The trange controls the domain
4877: (the angle) of the function, and the x and y ranges control the range of the
4878: graph in the x and y directions. Each of these ranges, as well as the
4879: rrange, may be autoscaled or set explicitly. See `set xrange` for details
4880: of all the `set range` commands.
4881:
4882: Example:
4883: set polar
4884: plot t*sin(t)
4885: plot [-2*pi:2*pi] [-3:3] [-3:3] t*sin(t)
4886:
4887: The first `plot` uses the default polar angular domain of 0 to 2*pi. The
4888: radius and the size of the graph are scaled automatically. The second `plot`
4889: expands the domain, and restricts the size of the graph to [-3:3] in both
4890: directions.
4891:
4892: You may want to `set size square` to have `gnuplot` try to make the aspect
4893: ratio equal to unity, so that circles look circular.
1.1.1.2 ! maekawa 4894: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/polar.html">Polar demos </a>
! 4895: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/poldat.html">Polar Data Plot. </a>
1.1 maekawa 4896: 3 rmargin
4897: ?commands set rmargin
4898: ?set rmargin
4899: ?rmargin
4900: The command `set rmargin` sets the size of the right margin. Please see
4901: `set margin` for details.
4902: 3 rrange
4903: ?commands set rrange
4904: ?commands show rrange
4905: ?set rrange
4906: ?show rrange
4907: ?rrange
4908: The `set rrange` command sets the range of the radial coordinate for a
4909: graph in polar mode. Please see `set xrange` for details.
4910: 3 samples
4911: ?commands set samples
4912: ?commands show samples
4913: ?set samples
4914: ?show samples
4915: ?samples
4916: The sampling rate of functions, or for interpolating data, may be changed
4917: by the `set samples` command.
4918:
4919: Syntax:
4920: set samples <samples_1> {,<samples_2>}
4921: show samples
4922:
4923: By default, sampling is set to 100 points. A higher sampling rate will
4924: produce more accurate plots, but will take longer. This parameter has no
4925: effect on data file plotting unless one of the interpolation/approximation
4926: options is used. See `plot smooth` re 2-d data and `set cntrparam` and
4927: `set dgrid3d` re 3-d data.
4928:
4929: When a 2-d graph is being done, only the value of <samples_1> is relevant.
4930:
4931: When a surface plot is being done without the removal of hidden lines, the
4932: value of samples specifies the number of samples that are to be evaluated for
4933: the isolines. Each iso-v line will have <sample_1> samples and each iso-u
4934: line will have <sample_2> samples. If you only specify <samples_1>,
4935: <samples_2> will be set to the same value as <samples_1>. See also `set
4936: isosamples`.
4937: 3 size
4938: ?commands set size
4939: ?commands show size
4940: ?set size
4941: ?show size
4942: ?size
4943: The `set size` command scales the displayed size of the plot.
4944:
4945: Syntax:
4946: set size {{no}square | ratio <r> | noratio} {<xscale>,<yscale>}
4947: show size
4948:
4949: The <xscale> and <yscale> values are the scaling factors for the size of the
4950: plot, which includes the graph and the margins.
4951:
4952: `ratio` causes `gnuplot` to try to create a graph with an aspect ratio of <r>
4953: (the ratio of the y-axis length to the x-axis length) within the portion of
4954: the plot specified by <xscale> and <yscale>.
4955:
4956: The meaning of a negative value for <r> is different. If <r>=-1, gnuplot
4957: tries to set the scales so that the unit has the same length on both the x
4958: and y axes (suitable for geographical data, for instance). If <r>=-2, the
4959: unit on y has twice the length of the unit on x, and so on.
4960:
4961: The success of `gnuplot` in producing the requested aspect ratio depends on
4962: the terminal selected. The graph area will be the largest rectangle of
4963: aspect ratio <r> that will fit into the specified portion of the output
4964: (leaving adequate margins, of course).
4965:
4966: `square` is a synonym for `ratio 1`.
4967:
4968: Both `noratio` and `nosquare` return the graph to the default aspect ratio
4969: of the terminal, but do not return <xscale> or <yscale> to their default
4970: values (1.0).
4971:
4972: `ratio` and `square` have no effect on 3-d plots.
4973:
4974: `set size` is relative to the default size, which differs from terminal to
4975: terminal. Since `gnuplot` fills as much of the available plotting area as
4976: possible by default, it is safer to use `set size` to decrease the size of
4977: a plot than to increase it. See `set terminal` for the default sizes.
4978:
4979: On some terminals, changing the size of the plot will result in text being
4980: misplaced.
4981:
4982: Examples:
4983:
4984: To set the size to normal size use:
4985: set size 1,1
4986:
4987: To make the graph half size and square use:
4988: set size square 0.5,0.5
4989:
4990: To make the graph twice as high as wide use:
4991: set size ratio 2
4992:
1.1.1.2 ! maekawa 4993: ^<a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/airfoil.html"> See demo. </a>
1.1 maekawa 4994: 3 style
4995: ?commands set function style
4996: ?commands show function style
4997: ?commands set data style
4998: ?commands show data style
4999: ?set function style
5000: ?show function style
5001: ?set data style
5002: ?show data style
5003: ?set style
5004: ?show style
5005: Default styles are chosen with the `set function style` and `set data style`
5006: commands. See `plot with` for information about how to override the default
5007: plotting style for individual functions and data sets.
5008:
5009: Syntax:
5010: set function style <style>
5011: set data style <style>
5012: show function style
5013: show data style
5014:
5015: The types used for all line and point styles (i.e., solid, dash-dot, color,
5016: etc. for lines; circles, squares, crosses, etc. for points) will be either
5017: those specified on the `plot` or `splot` command or will be chosen
5018: sequentially from the types available to the terminal in use. Use the
5019: command `test` to see what is available.
5020:
5021: None of the styles requiring more than two columns of information (e.g.,
5022: `errorbars`) can be used with `splot`s or function `plot`s. Neither `boxes`
5023: nor any of the `steps` styles can be used with `splot`s. If an inappropriate
5024: style is specified, it will be changed to `points`.
5025:
5026: For 2-d data with more than two columns, `gnuplot` is picky about the allowed
5027: `errorbar` styles. The `using` option on the `plot` command can be used to
5028: set up the correct columns for the style you want. (In this discussion,
5029: "column" will be used to refer both to a column in the data file and an entry
5030: in the `using` list.)
5031:
5032: For three columns, only `xerrorbars`, `yerrorbars` (or `errorbars`), `boxes`,
5033: and `boxerrorbars` are allowed. If another plot style is used, the style
5034: will be changed to `yerrorbars`. The `boxerrorbars` style will calculate the
5035: boxwidth automatically.
5036:
5037: For four columns, only `xerrorbars`, `yerrorbars` (or `errorbars`),
5038: `xyerrorbars`, `boxxyerrorbars`, and `boxerrorbars` are allowed. An illegal
5039: style will be changed to `yerrorbars`.
5040:
5041: Five-column data allow only the `boxerrorbars`, `financebars`, and
5042: `candlesticks` styles. (The last two of these are primarily used for plots
5043: of financial prices.) An illegal style will be changed to `boxerrorbars`
5044: before plotting.
5045:
5046: Six- and seven-column data only allow the `xyerrorbars` and `boxxyerrorbars`
5047: styles. Illegal styles will be changed to `xyerrorbars` before plotting.
5048:
5049: For more information about error bars, please see `plot errorbars`.
5050: 4 boxerrorbars
5051: ?commands set style boxerrorbars
5052: ?set style boxerrorbars
5053: ?style boxerrorbars
5054: ?boxerrorbars
5055: The `boxerrorbars` style is only relevant to 2-d data plotting. It is a
5056: combination of the `boxes` and `yerrorbars` styles. The boxwidth will come
5057: from the fourth column if the y errors are in the form of "ydelta" and the
5058: boxwidth was not previously set equal to -2.0 (`set boxwidth -2.0`) or from
5059: the fifth column if the y errors are in the form of "ylow yhigh". The
5060: special case `boxwidth = -2.0` is for four-column data with y errors in the
5061: form "ylow yhigh". In this case the boxwidth will be calculated so that each
5062: box touches the adjacent boxes. The width will also be calculated in cases
5063: where three-column data are used.
5064:
5065: The box height is determined from the y error in the same way as it is for
5066: the `yerrorbars` style---either from y-ydelta to y+ydelta or from ylow to
5067: yhigh, depending on how many data columns are provided.
5068: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html"> See Demo. </a>
5069: 4 boxes
5070: ?commands set style boxes
5071: ?commands set style bargraph
5072: ?set style boxes
5073: ?set style bargraph
5074: ?style boxes
5075: ?style bargraph
5076: ?boxes
5077: ?bargraph
5078: The `boxes` style is only relevant to 2-d plotting. It draws a box centered
5079: about the given x coordinate from the x axis (not the graph border) to the
5080: given y coordinate. The width of the box is obtained in one of three ways.
5081: If it is a data plot and the data file has a third column, this will be used
5082: to set the width of the box. If not, if a width has been set using the `set
5083: boxwidth` command, this will be used. If neither of these is available, the
5084: width of each box will be calculated automatically so that it touches the
5085: adjacent boxes.
5086: 4 boxxyerrorbars
5087: ?commands set style boxxyerrorbars
5088: ?set style boxxyerrorbars
5089: ?style boxxyerrorbars
5090: ?boxxyerrorbars
5091: The `boxxyerrorbars` style is only relevant to 2-d data plotting. It is a
5092: combination of the `boxes` and `xyerrorbars` styles.
5093:
5094: The box width and height are determined from the x and y errors in the same
5095: way as they are for the `xyerrorbars` style---either from xlow to xhigh and
5096: from ylow to yhigh, or from x-xdelta to x+xdelta and from y-ydelta to
5097: y+ydelta , depending on how many data columns are provided.
5098: 4 candlesticks
5099: ?commands set style candlesticks
5100: ?set style candlesticks
5101: ?style candlesticks
5102: ?candlesticks
5103: The `candlesticks` style is only relevant for 2-d data plotting of financial
5104: data. Five columns of data are required; in order, these should be the x
5105: coordinate (most likely a date) and the opening, low, high, and closing
5106: prices. The symbol is an open rectangle, centered horizontally at the x
5107: coordinate and limited vertically by the opening and closing prices. A
5108: vertical line segment at the x coordinate extends up from the top of the
5109: rectangle to the high price and another down to the low. The width of the
5110: rectangle may be changed by `set bar`. The symbol will be unchanged if the
5111: low and high prices are interchanged or if the opening and closing prices
5112: are interchanged. See `set bar` and `financebars`.
5113: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/finance/finance.html"> See demos.</a>
5114: 4 dots
5115: ?commands set style dots
5116: ?set style dots
5117: ?style dots
5118: ?dots
5119: The `dots` style plots a tiny dot at each point; this is useful for scatter
5120: plots with many points.
5121: 4 financebars
5122: ?commands set style financebars
5123: ?set style financebars
5124: ?style financebars
5125: ?financebars
5126: The `financebars` style is only relevant for 2-d data plotting of financial
5127: data. Five columns of data are required; in order, these should be the x
5128: coordinate (most likely a date) and the opening, low, high, and closing
5129: prices. The symbol is a vertical line segment, located horizontally at the x
5130: coordinate and limited vertically by the high and low prices. A horizontal
5131: tic on the left marks the opening price and one on the right marks the
5132: closing price. The length of these tics may be changed by `set bar`. The
5133: symbol will be unchanged if the high and low prices are interchanged. See
5134: `set bar` and `candlesticks`.
5135: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/finance/finance.html"> See demos.</a>
5136: 4 fsteps
5137: ?commands set style fsteps
5138: ?set style fsteps
5139: ?style fsteps
5140: ?fsteps
5141: The `fsteps` style is only relevant to 2-d plotting. It connects consecutive
5142: points with two line segments: the first from (x1,y1) to (x1,y2) and the
5143: second from (x1,y2) to (x2,y2).
1.1.1.2 ! maekawa 5144: ^<a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/steps.html"> See demo. </a>
1.1 maekawa 5145: 4 histeps
5146: ?commands set style histeps
5147: ?set style histeps
5148: ?style histeps
5149: ?histeps
5150: The `histeps` style is only relevant to 2-d plotting. It is intended for
5151: plotting histograms. Y-values are assumed to be centered at the x-values;
5152: the point at x1 is represented as a horizontal line from ((x0+x1)/2,y1) to
5153: ((x1+x2)/2,y1). The lines representing the end points are extended so that
5154: the step is centered on at x. Adjacent points are connected by a vertical
5155: line at their average x, that is, from ((x1+x2)/2,y1) to ((x1+x2)/2,y2).
5156:
5157: If `autoscale` is in effect, it selects the xrange from the data rather than
5158: the steps, so the end points will appear only half as wide as the others.
1.1.1.2 ! maekawa 5159: ^<a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/steps.html"> See demo. </a>
1.1 maekawa 5160:
5161: `histeps` is only a plotting style; `gnuplot` does not have the ability to
5162: create bins and determine their population from some data set.
5163: 4 impulses
5164: ?commands set style impulses
5165: ?set style impulses
5166: ?style impulses
5167: ?impulses
5168: The `impulses` style displays a vertical line from the x axis (not the graph
5169: border), or from the grid base for `splot`, to each point.
5170: 4 lines
5171: ?commands set style lines
5172: ?set style lines
5173: ?style lines
5174: ?lines
5175: The `lines` style connects adjacent points with straight line segments.
5176: 4 linespoints
5177: ?commands set style linespoints
5178: ?commands set style lp
5179: ?set style linespoints
5180: ?set style lp
5181: ?style linespoints
5182: ?style lp
5183: ?linespoints
5184: ?lp
5185: The `linespoints` style does both `lines` and `points`, that is, it draws a
5186: small symbol at each point and then connects adjacent points with straight
5187: line segments. The command `set pointsize` may be used to change the size of
5188: the points. See `set pointsize` for its usage.
5189:
5190: `linespoints` may be abbreviated `lp`.
5191: 4 points
5192: ?commands set style points
5193: ?set style points
5194: ?style points
5195: ?points
5196: The `points` style displays a small symbol at each point. The command `set
5197: pointsize` may be used to change the size of the points. See `set pointsize`
5198: for its usage.
5199: 4 steps
5200: ?commands set style steps
5201: ?set style steps
5202: ?style steps
5203: ?steps
5204: The `steps` style is only relevant to 2-d plotting. It connects consecutive
5205: points with two line segments: the first from (x1,y1) to (x2,y1) and the
5206: second from (x2,y1) to (x2,y2).
1.1.1.2 ! maekawa 5207: ^<a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/steps.html"> See demo. </a>
1.1 maekawa 5208: 4 vector
5209: ?commands set style vector
5210: ?set style vector
5211: ?style vector
5212: ?vector
5213: The `vector` style draws a vector from (x,y) to (x+xdelta,y+ydelta). Thus
5214: it requires four columns of data. It also draws a small arrowhead at the
5215: end of the vector.
5216:
5217: The `vector` style is still experimental: it doesn't get clipped properly
5218: and other things may also be wrong with it. Use it at your own risk.
5219: 4 xerrorbars
5220: ?commands set style xerrorbars
5221: ?set style xerrorbars
5222: ?style xerrorbars
5223: ?xerrorbars
5224: The `xerrorbars` style is only relevant to 2-d data plots. `xerrorbars` is
5225: like `dots`, except that a horizontal error bar is also drawn. At each point
5226: (x,y), a line is drawn from (xlow,y) to (xhigh,y) or from (x-xdelta,y) to
5227: (x+xdelta,y), depending on how many data columns are provided. A tic mark
5228: is placed at the ends of the error bar (unless `set bar` is used---see `set
5229: bar` for details).
5230: 4 xyerrorbars
5231: ?commands set style xyerrorbars
5232: ?set style xyerrorbars
5233: ?style xyerrorbars
5234: ?xyerrorbars
5235: The `xyerrorbars` style is only relevant to 2-d data plots. `xyerrorbars` is
5236: like `dots`, except that horizontal and vertical error bars are also drawn.
5237: At each point (x,y), lines are drawn from (x,y-ydelta) to (x,y+ydelta) and
5238: from (x-xdelta,y) to (x+xdelta,y) or from (x,ylow) to (x,yhigh) and from
5239: (xlow,y) to (xhigh,y), depending upon the number of data columns provided. A
5240: tic mark is placed at the ends of the error bar (unless `set bar` is
5241: used---see `set bar` for details).
5242:
5243: If data are provided in an unsupported mixed form, the `using` filter on the
5244: `plot` command should be used to set up the appropriate form. For example,
5245: if the data are of the form (x,y,xdelta,ylow,yhigh), then you can use
5246:
5247: plot 'data' using 1:2:($1-$3),($1+$3),4,5 with xyerrorbars
5248: 4 yerrorbars
5249: ?commands set style yerrorbars
5250: ?commands set style errorbars
5251: ?set style yerrorbars
5252: ?set style errorbars
5253: ?style yerrorbars
5254: ?style errorbars
5255: ?yerrorbars
5256: ?errorbars
5257: The `yerrorbars` (or `errorbars`) style is only relevant to 2-d data plots.
5258: `yerrorbars` is like `dots`, except that a vertical error bar is also drawn.
5259: At each point (x,y), a line is drawn from (x,y-ydelta) to (x,y+ydelta) or
5260: from (x,ylow) to (x,yhigh), depending on how many data columns are provided.
5261: A tic mark is placed at the ends of the error bar (unless `set bar` is
5262: used---see `set bar` for details).
5263: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html"> See demo. </a>
5264: 3 surface
5265: ?commands set surface
5266: ?commands set nosurface
5267: ?commands show surface
5268: ?set surface
5269: ?set nosurface
5270: ?show surface
5271: ?surface
5272: ?nosurface
5273: The command `set surface` controls the display of surfaces by `splot`.
5274:
5275: Syntax:
5276: set surface
5277: set nosurface
5278: show surface
5279:
5280: The surface is drawn with the style specifed by `with`, or else the
5281: appropriate style, data or function.
5282:
5283: Whenever `set nosurface` is issued, `splot` will not draw points or lines
5284: corresponding to the function or data file points. Contours may be still be
5285: drawn on the surface, depending on the `set contour` option. `set nosurface;
5286: set contour base` is useful for displaying contours on the grid base. See
5287: also `set contour`.
5288: ^ <h2> Terminal Types </h2>
5289: 3 terminal
5290: ?commands set terminal
5291: ?commands show terminal
5292: ?set terminal
5293: ?set term
5294: ?show terminal
5295: ?terminal
5296: ?term
5297: `gnuplot` supports many different graphics devices. Use `set terminal` to
5298: tell `gnuplot` what kind of output to generate. Use `set output` to redirect
5299: that output to a file or device.
5300:
5301: Syntax:
5302: set terminal {<terminal-type>}
5303: show terminal
5304:
5305: If <terminal-type> is omitted, `gnuplot` will list the available terminal
5306: types. <terminal-type> may be abbreviated.
5307:
5308: If both `set terminal` and `set output` are used together, it is safest to
5309: give `set terminal` first, because some terminals set a flag which is needed
5310: in some operating systems.
5311:
5312: Several terminals have additional options. For example, see `dumb`,
5313: `iris4d`, `hpljii` or `postscript`.
5314:
5315: This document may describe drivers that are not available to you because they
5316: were not installed, or it may not describe all the drivers that are available
5317: to you, depending on its output format.
5318: <4 -- all terminal stuff is pulled from the .trm files
5319: 3 tics
5320: ?commands set tics
5321: ?commands show tics
5322: ?set tics
5323: ?show tics
5324: ?tics
5325: The `set tics` command can be used to change the tics to be drawn outwards.
5326:
5327: Syntax:
5328: set tics {<direction>}
5329: show tics
5330:
5331: where <direction> may be `in` (the default) or `out`.
5332:
5333: See also `set xtics` for more control of major (labelled) tic marks and `set
5334: mxtics` for control of minor tic marks.
5335: 3 ticslevel
5336: ?commands set ticslevel
5337: ?commands show ticslevel
5338: ?set ticslevel
5339: ?show ticslevel
5340: ?ticslevel
5341: Using `splot`, one can adjust the relative height of the vertical (Z) axis
5342: using `set ticslevel`. The numeric argument provided specifies the location
5343: of the bottom of the scale (as a fraction of the z-range) above the xy-plane.
5344: The default value is 0.5. Negative values are permitted, but tic labels on
5345: the three axes may overlap.
5346:
5347: To place the xy-plane at a position 'pos' on the z-axis, `ticslevel` should
5348: be set equal to (pos - zmin) / (zmin - zmax).
5349:
5350: Syntax:
5351: set ticslevel {<level>}
5352: show tics
5353:
5354: See also `set view`.
5355: 3 ticscale
5356: ?commands set ticscale
5357: ?commands show ticscale
5358: ?set ticscale
5359: ?show ticscale
5360: ?ticscale
5361: The size of the tic marks can be adjusted with `set ticscale`.
5362:
5363: Syntax:
5364: set ticscale {<major> {<minor>}}
5365: show tics
5366:
5367: If <minor> is not specified, it is 0.5*<major>. The default size is 1.0 for
5368: major tics and 0.5 for minor tics. Note that it is possible to have the tic
5369: marks pointing outward by specifying a negative size.
5370: 3 timestamp
5371: ?commands set timestamp
5372: ?commands set time
5373: ?commands set notimestamp
5374: ?commands show timestamp
5375: ?set timestamp
5376: ?set time
5377: ?set notimestamp
5378: ?show timestamp
5379: ?timestamp
5380: ?notimestamp
5381: The command `set timestamp` places the time and date of the plot in the left
5382: margin.
5383:
5384: Syntax:
5385: set timestamp {"<format>"} {top|bottom} {{no}rotate}
5386: {<xoff>}{,<yoff>} {"<font>"}
5387: set notimestamp
5388: show timestamp
5389:
5390: The format string allows you to choose the format used to write the date and
5391: time. Its default value is what asctime() uses: "%a %b %d %H:%M:%S %Y"
5392: (weekday, month name, day of the month, hours, minutes, seconds, four-digit
5393: year). With `top` or `bottom` you can place the timestamp at the top or
5394: bottom of the left margin (default: bottom). `rotate` lets you write the
5395: timestamp vertically, if your terminal supports vertical text. The constants
5396: <xoff> and <off> are offsets from the default position given in character
5397: screen coordinates. <font> is used to specify the font with which the time
5398: is to be written.
5399:
5400: The abbreviation `time` may be used in place of `timestamp`.
5401:
5402: Example:
5403: set timestamp "%d/%m/%y %H:%M" 80,-2 "Helvetica"
5404:
5405: See `set timefmt` for more information about time format strings.
5406: 3 timefmt
5407: ?commands set timefmt
5408: ?commands show timefmt
5409: ?set timefmt
5410: ?show timefmt
5411: ?timefmt
5412: This command applies to timeseries where data are composed of dates/times.
5413: It has no meaning unless the command `set xdata time` is given also.
5414:
5415: Syntax:
5416: set timefmt "<format string>"
5417: show timefmt
5418:
5419: The string argument tells `gnuplot` how to read timedata from the datafile.
5420: The valid formats are:
5421:
5422: @start table - first is interactive cleartext form
5423: Format Explanation
5424: %d day of the month, 1--31
5425: %m month of the year, 1--12
5426: %y year, 0--99
5427: %Y year, 4-digit
5428: %j day of the year, 1--365
5429: %H hour, 0--24
5430: %M minute, 0--60
5431: %S second, 0--60
5432: %b three-character abbreviation of the name of the month
5433: %B name of the month
5434: #\begin{tabular}{|cl|} \hline
5435: #\multicolumn{2}{|c|}{Time Series timedata Format Specifiers}\\
5436: #\hline \hline
5437: #Format & Explanation \\ \hline
5438: #\verb@%d@ & day of the month, 1--31 \\
5439: #\verb@%m@ & month of the year, 1--12 \\
5440: #\verb@%y@ & year, 0--99 \\
5441: #\verb@%Y@ & year, 4-digit \\
5442: #\verb@%j@ & day of the year, 1--365 \\
5443: #\verb@%H@ & hour, 0--24 \\
5444: #\verb@%M@ & minute, 0--60 \\
5445: #\verb@%S@ & second, 0--60 \\
5446: #\verb@%b@ & three-character abbreviation of the name of the month \\
5447: #\verb@%B@ & name of the month \\
5448: %c l .
5449: %Format@Explanation
5450: %_
5451: %%d@day of the month, 1--31
5452: %%m@month of the year, 1--12
5453: %%y@year, 0--99
5454: %%Y@year, 4-digit
5455: %%j@day of the year, 1--365
5456: %%H@hour, 0--24
5457: %%M@minute, 0--60
5458: %%S@second, 0--60
5459: %%b@three-character abbreviation of the name of the month
5460: %%B@name of the month
5461: %_
5462: @end table
5463: Any character is allowed in the string, but must match exactly. \t (tab) is
5464: recognized. Backslash-octals (\nnn) are converted to char. If there is no
5465: separating character between the time/date elements, then %d, %m, %y, %H, %M
5466: and %S read two digits each, %Y reads four digits and %j reads three digits.
5467: %b requires three characters, and %B requires as many as it needs.
5468:
5469: Spaces are treated slightly differently. A space in the string stands for
5470: zero or more whitespace characters in the file. That is, "%H %M" can be used
5471: to read "1220" and "12 20" as well as "12 20".
5472:
5473: Each set of non-blank characters in the timedata counts as one column in the
5474: `using n:n` specification. Thus `11:11 25/12/76 21.0` consists of three
5475: columns. To avoid confusion, `gnuplot` requires that you provide a complete
5476: `using` specification if your file contains timedata.
5477:
5478: Since `gnuplot` cannot read non-numerical text, if the date format includes
5479: the day or month in words, the format string must exclude this text. But
5480: it can still be printed with the "%a", "%A", "%b", or "%B" specifier: see
5481: `set format` for more details about these and other options for printing
5482: timedata. (`gnuplot` will determine the proper month and weekday from the
5483: numerical values.)
5484:
5485: See also `set xdata` and `Time/date` for more information.
5486:
5487: Example:
5488: set timefmt "%d/%m/%Y\t%H:%M"
5489: tells `gnuplot` to read date and time separated by tab. (But look closely at
5490: your data---what began as a tab may have been converted to spaces somewhere
5491: along the line; the format string must match what is actually in the file.)
1.1.1.2 ! maekawa 5492: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/timedat.html"> Time Data Demo </a>
1.1 maekawa 5493: 3 title
5494: ?commands set title
5495: ?commands show title
5496: ?set title
5497: ?show title
5498: ?title
5499: The `set title` command produces a plot title that is centered at the top of
5500: the plot. `set title` is a special case of `set label`.
5501:
5502: Syntax:
5503: set title {"<title-text>"} {<xoff>}{,<yoff>} {"<font>,{<size>}"}
5504: show title
5505:
5506: Specifying constants <xoff> or <yoff> as optional offsets for the title will
5507: move the title <xoff> or <yoff> character screen coordinates (not graph
5508: coordinates). For example, "`set title ,-1`" will change only the y offset
5509: of the title, moving the title down by roughly the height of one character.
5510:
5511: <font> is used to specify the font with which the title is to be written;
5512: the units of the font <size> depend upon which terminal is used.
5513:
5514: `set title` with no parameters clears the title.
5515:
5516: See `syntax` for details about the processing of backslash sequences and
5517: the distinction between single- and double-quotes.
5518: 3 tmargin
5519: ?commands set tmargin
5520: ?set tmargin
5521: ?tmargin
5522: The command `set tmargin` sets the size of the top margin. Please see
5523: `set margin` for details.
5524: 3 trange
5525: ?commands set trange
5526: ?commands show trange
5527: ?set trange
5528: ?show trange
5529: ?trange
5530: The `set trange` command sets the parametric range used to compute x and y
5531: values when in parametric or polar modes. Please see `set xrange` for
5532: details.
5533: 3 urange
5534: ?commands set urange
5535: ?commands show urange
5536: ?set urange
5537: ?show urange
5538: ?urange
5539: The `set urange` and `set vrange` commands set the parametric ranges used
5540: to compute x, y, and z values when in `splot` parametric mode. Please see
5541: `set xrange` for details.
5542: 3 variables
5543: ?commands show variables
5544: ?show variables
5545: The `show variables` command lists all user-defined variables and their
5546: values.
5547:
5548: Syntax:
5549: show variables
5550: 3 version
5551: ?show version
5552: The `show version` command lists the version of gnuplot being run, its last
5553: modification date, the copyright holders, and email addresses for the FAQ,
5554: the info-gnuplot mailing list, and reporting bugs--in short, the information
5555: listed on the screen when the program is invoked interactively.
5556:
5557: Syntax:
5558: show version {long}
5559:
5560: When the `long` option is given, it also lists the operating system, the
5561: compilation options used when `gnuplot` was installed, the location of the
5562: help file, and (again) the useful email addresses.
5563: 3 view
5564: ?commands set view
5565: ?commands show view
5566: ?set view
5567: ?show view
5568: ?view
5569: The `set view` command sets the viewing angle for `splot`s. It controls how
5570: the 3-d coordinates of the plot are mapped into the 2-d screen space. It
5571: provides controls for both rotation and scaling of the plotted data, but
5572: supports orthographic projections only.
5573:
5574: Syntax:
5575: set view <rot_x> {,{<rot_z>}{,{<scale>}{,<scale_z>}}}
5576: show view
5577:
5578: where <rot_x> and <rot_z> control the rotation angles (in degrees) in a
5579: virtual 3-d coordinate system aligned with the screen such that initially
5580: (that is, before the rotations are performed) the screen horizontal axis is
5581: x, screen vertical axis is y, and the axis perpendicular to the screen is z.
5582: The first rotation applied is <rot_x> around the x axis. The second rotation
5583: applied is <rot_z> around the new z axis.
5584:
5585: <rot_x> is bounded to the [0:180] range with a default of 60 degrees, while
5586: <rot_z> is bounded to the [0:360] range with a default of 30 degrees.
5587: <scale> controls the scaling of the entire `splot`, while <scale_z> scales
5588: the z axis only. Both scales default to 1.0.
5589:
5590: Examples:
5591: set view 60, 30, 1, 1
5592: set view ,,0.5
5593:
5594: The first sets all the four default values. The second changes only scale,
5595: to 0.5.
5596:
5597: See also `set ticslevel`.
5598: 3 vrange
5599: ?commands set vrange
5600: ?commands show vrange
5601: ?set vrange
5602: ?show vrange
5603: ?vrange
5604: The `set urange` and `set vrange` commands set the parametric ranges used
5605: to compute x, y, and z values when in `splot` parametric mode. Please see
5606: `set xrange` for details.
5607: 3 x2data
5608: ?commands set x2data
5609: ?commands show x2data
5610: ?set x2data
5611: ?show x2data
5612: ?x2data
5613: The `set x2data` command sets data on the x2 (top) axis to timeseries
5614: (dates/times). Please see `set xdata`.
5615: 3 x2dtics
5616: ?commands set x2dtics
5617: ?commands set nox2dtics
5618: ?commands show x2dtics
5619: ?set x2dtics
5620: ?set nox2dtics
5621: ?show x2dtics
5622: ?x2dtics
5623: ?nox2dtics
5624: The `set x2dtics` command changes tics on the x2 (top) axis to days of the
5625: week. Please see `set xdtics` for details.
5626: 3 x2label
5627: ?commands set x2label
5628: ?commands show x2label
5629: ?set x2label
5630: ?show x2label
5631: ?x2label
5632: The `set x2label` command sets the label for the x2 (top) axis. Please see
5633: `set xlabel`.
5634: 3 x2mtics
5635: ?commands set x2mtics
5636: ?commands set nox2mtics
5637: ?commands show x2mtics
5638: ?set x2mtics
5639: ?set nox2mtics
5640: ?show x2mtics
5641: ?x2mtics
5642: ?nox2mtics
5643: The `set x2mtics` command changes tics on the x2 (top) axis to months of the
5644: year. Please see `set xmtics` for details.
5645: 3 x2range
5646: ?commands set x2range
5647: ?commands show x2range
5648: ?set x2range
5649: ?show x2range
5650: ?x2range
5651: The `set x2range` command sets the horizontal range that will be displayed on
5652: the x2 (top) axis. Please see `set xrange` for details.
5653: 3 x2tics
5654: ?commands set x2tics
5655: ?commands set nox2tics
5656: ?commands show x2tics
5657: ?set x2tics
5658: ?set nox2tics
5659: ?show x2tics
5660: ?x2tics
5661: ?nox2tics
5662: The `set x2tics` command controls major (labelled) tics on the x2 (top) axis.
5663: Please see `set xtics` for details.
5664: 3 x2zeroaxis
5665: ?commands set x2zeroaxis
5666: ?commands set nox2zeroaxis
5667: ?commands show x2zeroaxis
5668: ?set x2zeroaxis
5669: ?set nox2zeroaxis
5670: ?show x2zeroaxis
5671: ?x2zeroaxis
5672: ?nox2zeroaxis
5673: The `set x2zeroaxis` command draws a line at the origin of the x2 (top) axis
5674: (y2 = 0). For details, please see
5675: `set zeroaxis`.
5676: 3 xdata
5677: ?commands set xdata
5678: ?commands show xdata
5679: ?set xdata
5680: ?show xdata
5681: ?xdata
5682: This command sets the datatype on the x axis to time/date. A similar command
5683: does the same thing for each of the other axes.
5684:
5685: Syntax:
5686: set xdata {time}
5687: show xdata
5688:
5689: The same syntax applies to `ydata`, `zdata`, `x2data` and `y2data`.
5690:
5691: The `time` option signals that the datatype is indeed time/date. If the
5692: option is not specified, the datatype reverts to normal.
5693:
5694: See `set timefmt` to tell `gnuplot` how to read date or time data. The
5695: time/date is converted to seconds from start of the century. There is
5696: currently only one timefmt, which implies that all the time/date columns must
5697: confirm to this format. Specification of ranges should be supplied as quoted
5698: strings according to this format to avoid interpretation of the time/date as
5699: an expression.
5700:
5701: The function 'strftime' (type "man strftime" on unix to look it up) is used
5702: to print tic-mark labels. `gnuplot` tries to figure out a reasonable format
5703: for this unless the `set format x "string"` has supplied something that does
5704: not look like a decimal format (more than one '%' or neither %f nor %g).
5705:
5706: See also `Time/date` for more information.
5707: 3 xdtics
5708: ?commands set xdtics
5709: ?commands set noxdtics
5710: ?commands show xdtics
5711: ?set xdtics
5712: ?set noxdtics
5713: ?show xdtics
5714: ?xdtics
5715: ?noxdtics
5716: The `set xdtics` commands converts the x-axis tic marks to days of the week
5717: where 0=Sun and 6=Sat. Overflows are converted modulo 7 to dates. `set
5718: noxdtics` returns the labels to their default values. Similar commands do
5719: the same things for the other axes.
5720:
5721: Syntax:
5722: set xdtics
5723: set noxdtics
5724: show xdtics
5725:
5726: The same syntax applies to `ydtics`, `zdtics`, `x2dtics` and `y2dtics`.
5727:
5728: See also the `set format` command.
5729: 3 xlabel
5730: ?commands set xlabel
5731: ?commands show xlabel
5732: ?set xlabel
5733: ?show xlabel
5734: ?xlabel
5735: The `set xlabel` command sets the x axis label. Similar commands set labels
5736: on the other axes.
5737:
5738: Syntax:
5739: set xlabel {"<label>"} {<xoff>}{,<yoff>} {"<font>{,<size>}"}
5740: show xlabel
5741:
5742: The same syntax applies to `x2label`, `ylabel`, `y2label` and `zlabel`.
5743:
5744: Specifying the constants <xoff> or <yoff> as optional offsets for a label
5745: will move it <xoff> or <yoff> character widths or heights. For example,
5746: "` set xlabel -1`" will change only the x offset of the xlabel, moving the
5747: label roughly one character width to the left. The size of a character
5748: depends on both the font and the terminal.
5749:
5750: <font> is used to specify the font in which the label is written; the units
5751: of the font <size> depend upon which terminal is used.
5752:
5753: To clear a label, put no options on the command line, e.g., "`set y2label`".
5754:
5755: The default positions of the axis labels are as follows:
5756:
5757: xlabel: The x-axis label is centered below the bottom axis.
5758:
5759: ylabel: The position of the y-axis label depends on the terminal, and can be
5760: one of the following three positions:
5761:
5762: 1. Horizontal text flushed left at the top left of the plot. Terminals that
5763: cannot rotate text will probably use this method. If `set x2tics` is also
5764: in use, the ylabel may overwrite the left-most x2tic label. This may be
5765: remedied by adjusting the ylabel position or the left margin.
5766:
5767: 2. Vertical text centered vertically at the left of the plot. Terminals
5768: that can rotate text will probably use this method.
5769:
5770: 3. Horizontal text centered vertically at the left of the plot. The EEPIC,
5771: LaTeX and TPIC drivers use this method. The user must insert line breaks
5772: using \\ to prevent the ylabel from overwriting the plot. To produce a
5773: vertical row of characters, add \\ between every printing character (but this
5774: is ugly).
5775:
5776: zlabel: The z-axis label is centered along the z axis and placed in the space
5777: above the grid level.
5778:
5779: y2label: The y2-axis label is placed to the right of the y2 axis. The
5780: position is terminal-dependent in the same manner as is the y-axis label.
5781:
5782: x2label: The x2-axis label is placed above the top axis but below the plot
5783: title. It is also possible to create an x2-axis label by using new-line
5784: characters to make a multi-line plot title, e.g.,
5785:
5786: set title "This is the title\n\nThis is the x2label"
5787:
5788: Note that double quotes must be used. The same font will be used for both
5789: lines, of course.
5790:
5791: If you are not satisfied with the default position of an axis label, use `set
5792: label` instead--that command gives you much more control over where text is
5793: placed.
5794:
5795: Please see `set syntax` for further information about backslash processing
5796: and the difference between single- and double-quoted strings.
5797: 3 xmtics
5798: ?commands set xmtics
5799: ?commands set noxmtics
5800: ?commands show xmtics
5801: ?set xmtics
5802: ?set noxmtics
5803: ?show xmtics
5804: ?xmtics
5805: ?noxmtics
5806: The `set xmtics` commands converts the x-axis tic marks to months of the
5807: year where 1=Jan and 12=Dec. Overflows are converted modulo 12 to months.
5808: The tics are returned to their default labels by `set noxmtics`. Similar
5809: commands perform the same duties for the other axes.
5810:
5811: Syntax:
5812: set xmtics
5813: set noxmtics
5814: show xmtics
5815:
5816: The same syntax applies to `x2mtics`, `ymtics`, `y2mtics`, and `zmtics`.
5817:
5818: See also the `set format` command.
5819: 3 xrange
5820: ?commands set xrange
5821: ?commands show xrange
5822: ?set xrange
5823: ?show xrange
5824: ?xrange
5825: The `set xrange` command sets the horizontal range that will be displayed.
5826: A similar command exists for each of the other axes, as well as for the
5827: polar radius r and the parametric variables t, u, and v.
5828:
5829: Syntax:
5830: set xrange [{{<min>}:{<max>}}] {{no}reverse} {{no}writeback}
5831: show xrange
5832:
5833: where <min> and <max> terms are constants, expressions or an asterisk to set
5834: autoscaling. If the data are time/date, you must give the range as a quoted
5835: string according to the `set timefmt` format. Any value omitted will not be
5836: changed.
5837:
5838: The same syntax applies to `yrange`, `zrange`, `x2range`, `y2range`,
5839: `rrange`, `trange`, `urange` and `vrange`.
5840:
5841: The `reverse` option reverses the direction of the axis, e.g., `set xrange
5842: [0:1] reverse` will produce an axis with 1 on the left and 0 on the right.
5843: This is identical to the axis produced by `set xrange [1:0]`, of course.
5844: `reverse` is intended primarily for use with `autoscale`.
5845:
5846: The `writeback` option essentially saves the range found by `autoscale` in
5847: the buffers that would be filled by `set xrange`. This is useful if you wish
5848: to plot several functions together but have the range determined by only
5849: some of them. The `writeback` operation is performed during the `plot`
5850: execution, so it must be specified before that command. For example,
5851:
5852: set xrange [-10:10]
5853: set yrange [] writeback
5854: plot sin(x)
5855: set noautoscale y
5856: replot x/2
5857:
5858: results in a yrange of [-1:1] as found only from the range of sin(x); the
5859: [-5:5] range of x/2 is ignored. Executing `show yrange` after each command
5860: in the above example should help you understand what is going on.
5861:
5862: In 2-d, `xrange` and `yrange` determine the extent of the axes, `trange`
5863: determines the range of the parametric variable in parametric mode or the
5864: range of the angle in polar mode. Similarly in parametric 3-d, `xrange`,
5865: `yrange`, and `zrange` govern the axes and `urange` and `vrange` govern the
5866: parametric variables.
5867:
5868: In polar mode, `rrange` determines the radial range plotted. <rmin> acts as
5869: an additive constant to the radius, whereas <rmax> acts as a clip to the
5870: radius---no point with radius greater than <rmax> will be plotted. `xrange`
5871: and `yrange` are affected---the ranges can be set as if the graph was of
5872: r(t)-rmin, with rmin added to all the labels.
5873:
5874: Any range may be partially or totally autoscaled, although it may not make
5875: sense to autoscale a parametric variable unless it is plotted with data.
5876:
5877: Ranges may also be specified on the `plot` command line. A range given on
5878: the plot line will be used for that single `plot` command; a range given by
5879: a `set` command will be used for all subsequent plots that do not specify
5880: their own ranges. The same holds true for `splot`.
5881:
5882: Examples:
5883:
5884: To set the xrange to the default:
5885: set xrange [-10:10]
5886:
5887: To set the yrange to increase downwards:
5888: set yrange [10:-10]
5889:
5890: To change zmax to 10 without affecting zmin (which may still be autoscaled):
5891: set zrange [:10]
5892:
5893: To autoscale xmin while leaving xmax unchanged:
5894: set xrange [*:]
5895: 3 xtics
5896: ?commands set xtics
5897: ?commands set noxtics
5898: ?commands show xtics
5899: ?set xtics
5900: ?set noxtics
5901: ?show xtics
5902: ?xtics
5903: ?noxtics
5904: Fine control of the major (labelled) tics on the x axis is possible with the
5905: `set xtics` command. The tics may be turned off with the `set noxtics`
5906: command, and may be turned on (the default state) with `set xtics`. Similar
5907: commands control the major tics on the y, z, x2 and y2 axes.
5908:
5909: Syntax:
5910: set xtics {axis | border} {{no}mirror} {{no}rotate}
5911: { autofreq
5912: | <incr>
5913: | <start>, <incr> {,<end>}
5914: | ({"<label>"} <pos> {,{"<label>"} <pos>}...) }
5915: set noxtics
5916: show xtics
5917:
5918: The same syntax applies to `ytics`, `ztics`, `x2tics` and `y2tics`.
5919:
5920: `axis` or `border` tells `gnuplot` to put the tics (both the tics themselves
1.1.1.2 ! maekawa 5921: and the accompanying labels) along the axis or the border, respectively. If
! 5922: the axis is very close to the border, the `axis` option can result in tic
! 5923: labels overwriting other text written in the margin.
! 5924:
! 5925: `mirror` tells `gnuplot` to put unlabelled tics at the same positions on the
! 5926: opposite border. `nomirror` does what you think it does.
! 5927:
! 5928: `rotate` asks `gnuplot` to rotate the text through 90 degrees, which will be
! 5929: done if the terminal driver in use supports text rotation. `norotate`
! 5930: cancels this.
! 5931:
! 5932: The defaults are `border mirror norotate` for tics on the x and y axes, and
! 5933: `border nomirror norotate` for tics on the x2 and y2 axes. For the z axis,
! 5934: the the `{axis | border}` option is not available and the default is
! 5935: `nomirror`. If you do want to mirror the z-axis tics, you might want to
! 5936: create a bit more room for them with `set border`.
! 5937:
! 5938: `set xtics` with no options restores the default border or axis if xtics are
! 5939: being displayed; otherwise it has no effect. Any previously specified tic
! 5940: frequency or position {and labels} are retained.
1.1 maekawa 5941:
5942: Positions of the tics are calculated automatically by default or if the
5943: `autofreq` option is given; otherwise they may be specified in either of
5944: two forms:
5945:
5946: The implicit <start>, <incr>, <end> form specifies that a series of tics will
5947: be plotted on the axis between the values <start> and <end> with an increment
5948: of <incr>. If <end> is not given, it is assumed to be infinity. The
5949: increment may be negative. If neither <start> nor <end> is given, <start> is
5950: assumed to be negative infinity, <end> is assumed to be positive infinity,
5951: and the tics will be drawn at integral multiples of <step>. If the axis is
5952: logarithmic, the increment will be used as a multiplicative factor.
5953:
5954: Examples:
5955:
5956: Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
5957: set xtics 0,.5,10
5958:
5959: Make tics at ..., -10, -5, 0, 5, 10, ...
5960: set xtics 5
5961:
5962: Make tics at 1, 100, 1e4, 1e6, 1e8.
5963: set logscale x; set xtics 1,100,10e8
5964:
5965: The explicit ("<label>" <pos>, ...) form allows arbitrary tic positions or
5966: non-numeric tic labels. A set of tics is a set of positions, each with its
5967: own optional label. Note that the label is a string enclosed by quotes. It
5968: may be a constant string, such as "hello", may contain formatting information
5969: for converting the position into its label, such as "%3f clients", or may be
5970: empty, "". See `set format` for more information. If no string is given,
5971: the default label (numerical) is used. In this form, the tics do not need to
5972: be listed in numerical order.
5973:
5974: Examples:
5975: set xtics ("low" 0, "medium" 50, "high" 100)
5976: set xtics (1,2,4,8,16,32,64,128,256,512,1024)
5977: set ytics ("bottom" 0, "" 10, "top" 20)
5978:
5979: In the second example, all tics are labelled. In the third, only the end
5980: tics are labelled.
5981:
5982: However they are specified, tics will only be plotted when in range.
5983:
5984: Format (or omission) of the tic labels is controlled by `set format`, unless
5985: the explicit text of a labels is included in the `set xtic (`<label>`)` form.
5986:
5987: Minor (unlabelled) tics can be added by the `set mxtics` command.
5988:
5989: In case of timeseries data, position values must be given as quoted dates
5990: or times according to the format `timefmt`. If the <start>, <incr>, <end>
5991: form is used, <start> and <end> must be given according to `timefmt`, but
5992: <incr> must be in seconds. Times will be written out according to the format
5993: given on `set format`, however.
5994:
5995: Examples:
5996: set xdata time
5997: set timefmt "%d/%m"
5998: set format x "%b %d"
5999: set xrange ["01/12":"06/12"]
6000: set xtics "01/12", 172800, "05/12"
6001:
6002: set xdata time
6003: set timefmt "%d/%m"
6004: set format x "%b %d"
6005: set xrange ["01/12":"06/12"]
6006: set xtics ("01/12", "" "03/12", "05/12")
6007: Both of these will produce tics "Dec 1", "Dec 3", and "Dec 5", but in the
6008: second example the tic at "Dec 3" will be unlabelled.
6009:
6010: 3 xzeroaxis
6011: ?commands set xzeroaxis
6012: ?commands set noxzeroaxis
6013: ?commands show xzeroaxis
6014: ?set xzeroaxis
6015: ?set noxzeroaxis
6016: ?show xzeroaxis
6017: ?xzeroaxis
6018: ?noxzeroaxis
6019: The `set xzeroaxis` command draws a line at y = 0. For details, please see
6020: `set zeroaxis`.
6021: 3 y2data
6022: ?commands set y2data
6023: ?commands show y2data
6024: ?set y2data
6025: ?show y2data
6026: ?y2data
6027: The `set y2data` command sets y2 (right-hand) axis data to timeseries
6028: (dates/times). Please see `set xdata`.
6029: 3 y2dtics
6030: ?commands set y2dtics
6031: ?commands set noy2dtics
6032: ?set y2dtics
6033: ?set noy2dtics
6034: ?show y2dtics
6035: ?y2dtics
6036: ?noy2dtics
6037: The `set y2dtics` command changes tics on the y2 (right-hand) axis to days of
6038: the week. Please see `set xdtics` for details.
6039: 3 y2label
6040: ?commands set y2label
6041: ?commands show y2label
6042: ?set y2label
6043: ?show y2label
6044: ?y2label
6045: The `set y2dtics` command sets the label for the y2 (right-hand) axis.
6046: Please see `set xlabel`.
6047: 3 y2mtics
6048: ?commands set y2mtics
6049: ?commands set noy2mtics
6050: ?commands show y2mtics
6051: ?set y2mtics
6052: ?set noy2mtics
6053: ?show y2mtics
6054: ?y2mtics
6055: ?noy2mtics
6056: The `set y2mtics` command changes tics on the y2 (right-hand) axis to months
6057: of the year. Please see `set xmtics` for details.
6058: 3 y2range
6059: ?commands set y2range
6060: ?commands show y2range
6061: ?set y2range
6062: ?show y2range
6063: ?y2range
6064: The `set y2range` command sets the vertical range that will be displayed on
6065: the y2 (right-hand) axis. Please see `set xrange` for details.
6066: 3 y2tics
6067: ?commands set y2tics
6068: ?commands set noy2tics
6069: ?commands show y2tics
6070: ?set y2tics
6071: ?set noy2tics
6072: ?show y2tics
6073: ?y2tics
6074: ?noy2tics
6075: The `set y2tics` command controls major (labelled) tics on the y2 (right-hand)
6076: axis. Please see `set xtics` for details.
6077: 3 y2zeroaxis
6078: ?commands set y2zeroaxis
6079: ?commands set noy2zeroaxis
6080: ?commands show y2zeroaxis
6081: ?set y2zeroaxis
6082: ?set noy2zeroaxis
6083: ?show y2zeroaxis
6084: ?y2zeroaxis
6085: ?noy2zeroaxis
6086: The `set y2zeroaxis` command draws a line at the origin of the y2 (right-hand)
6087: axis (x2 = 0). For details, please see `set zeroaxis`.
6088: 3 ydata
6089: ?commands set ydata
6090: ?commands show ydata
6091: ?set ydata
6092: ?show ydata
6093: ?ydata
6094: Sets y-axis data to timeseries (dates/times). Please see `set xdata`.
6095: 3 ydtics
6096: ?commands set ydtics
6097: ?commands set noydtics
6098: ?commands show ydtics
6099: ?set ydtics
6100: ?set noydtics
6101: ?show ydtics
6102: ?ydtics
6103: ?noydtics
6104: The `set ydtics` command changes tics on the y axis to days of the week.
6105: Please see `set xdtics` for details.
6106: 3 ylabel
6107: ?commands set ylabel
6108: ?commands show ylabel
6109: ?set ylabel
6110: ?show ylabel
6111: ?ylabel
6112: This command sets the label for the y axis. Please see `set xlabel`.
6113: 3 ymtics
6114: ?commands set ymtics
6115: ?commands set noymtics
6116: ?commands show ymtics
6117: ?set ymtics
6118: ?set noymtics
6119: ?show ymtics
6120: ?ymtics
6121: ?noymtics
6122: The `set ymtics` command changes tics on the y axis to months of the year.
6123: Please see `set xmtics` for details.
6124: 3 yrange
6125: ?commands set yrange
6126: ?commands show yrange
6127: ?set yrange
6128: ?show yrange
6129: ?yrange
6130: The `set yrange` command sets the vertical range that will be displayed on
6131: the y axis. Please see `set xrange` for details.
6132: 3 ytics
6133: ?commands set ytics
6134: ?commands set noytics
6135: ?commands show ytics
6136: ?set ytics
6137: ?set noytics
6138: ?show ytics
6139: ?ytics
6140: ?noytics
6141: The `set ytics` command controls major (labelled) tics on the y axis.
6142: Please see `set xtics` for details.
6143: 3 yzeroaxis
6144: ?commands set yzeroaxis
6145: ?commands set noyzeroaxis
6146: ?commands show yzeroaxis
6147: ?set yzeroaxis
6148: ?set noyzeroaxis
6149: ?show yzeroaxis
6150: ?yzeroaxis
6151: ?noyzeroaxis
6152: The `set yzeroaxis` command draws a line at x = 0. For details, please see
6153: `set zeroaxis`.
6154: 3 zdata
6155: ?commands set zdata
6156: ?commands show zdata
6157: ?set zdata
6158: ?show zdata
6159: ?zdata
6160: Set zaxis date to timeseries (dates/times). Please see `set xdata`.
6161: 3 zdtics
6162: ?commands set zdtics
6163: ?commands set nozdtics
6164: ?commands show zdtics
6165: ?set zdtics
6166: ?set nozdtics
6167: ?show zdtics
6168: ?zdtics
6169: ?nozdtics
6170: The `set zdtics` command changes tics on the z axis to days of the week.
6171: Please see `set xdtics` for details.
6172: 3 zero
6173: ?commands set zero
6174: ?commands show zero
6175: ?set zero
6176: ?show zero
6177: ?zero
6178: The `zero` value is the default threshold for values approaching 0.0.
6179:
6180: Syntax:
6181: set zero <expression>
6182: show zero
6183:
6184: `gnuplot` will not plot a point if its imaginary part is greater in magnitude
6185: than the `zero` threshold. This threshold is also used in various other
6186: parts of `gnuplot` as a (crude) numerical-error threshold. The default
6187: `zero` value is 1e-8. `zero` values larger than 1e-3 (the reciprocal of the
6188: number of pixels in a typical bitmap display) should probably be avoided, but
6189: it is not unreasonable to set `zero` to 0.0.
6190: 3 zeroaxis
6191: ?commands set zeroaxis
6192: ?commands set nozeroaxis
6193: ?commands show zeroaxis
6194: ?set zeroaxis
6195: ?set nozeroaxis
6196: ?show zeroaxis
6197: ?zeroaxis
6198: ?nozeroaxis
6199: The x axis may be drawn by `set xzeroaxis` and removed by `set noxzeroaxis`.
6200: Similar commands behave similarly for the y, x2, and y2 axes.
6201:
6202: Syntax:
6203: set {x|x2|y|y2|}zeroaxis { {linestyle | ls <line_style>}
6204: | { linetype | lt <line_type>}
6205: { linewidth | lw <line_width>}}
6206: set no{x|x2|y|y2|}zeroaxis
6207: show {x|y|}zeroaxis
6208:
6209:
6210: By default, these options are off. The selected zero axis is drawn
6211: with a line of type <line_type> and width <line_width> (if supported
6212: by the terminal driver currently in use), or a user-defined style
6213: <line_style>.
6214:
6215: If no linetype is specified, any zero axes selected will be drawn
6216: using the axis linetype (linetype 0).
6217:
6218: `set zeroaxis l` is equivalent to `set xzeroaxis l; set yzeroaxis l`. `set
6219: nozeroaxis` is equivalent to `set noxzeroaxis; set noyzeroaxis`.
6220: 3 zlabel
6221: ?commands set zlabel
6222: ?commands show zlabel
6223: ?set zlabel
6224: ?show zlabel
6225: ?zlabel
6226: This command sets the label for the z axis. Please see `set xlabel`.
6227: 3 zmtics
6228: ?commands set zmtics
6229: ?commands set nozmtics
6230: ?commands show zmtics
6231: ?set zmtics
6232: ?set nozmtics
6233: ?show zmtics
6234: ?zmtics
6235: ?nozmtics
6236: The `set zmtics` command changes tics on the z axis to months of the year.
6237: Please see `set xmtics` for details.
6238: 3 zrange
6239: ?commands set zrange
6240: ?commands show zrange
6241: ?set zrange
6242: ?show zrange
6243: ?zrange
6244: The `set zrange` command sets the range that will be displayed on the z axis.
6245: The zrange is used only by `splot` and is ignored by `plot`. Please see `set
6246: xrange` for details.
6247: 3 ztics
6248: ?commands set ztics
6249: ?commands set noztics
6250: ?commands show ztics
6251: ?set ztics
6252: ?set noztics
6253: ?show ztics
6254: ?ztics
6255: ?noztics
6256: The `set ztics` command controls major (labelled) tics on the z axis.
6257: Please see `set xtics` for details.
6258: 2 shell
6259: ?commands shell
6260: ?shell
6261: The `shell` command spawns an interactive shell. To return to `gnuplot`,
6262: type `logout` if using VMS, `exit` or the END-OF-FILE character if using
6263: Unix, `endcli` if using AmigaOS, or `exit` if using MS-DOS or OS/2.
6264:
6265: A single shell command may be spawned by preceding it with the ! character
6266: ($ if using VMS) at the beginning of a command line. Control will return
6267: immediately to `gnuplot` after this command is executed. For example, in
6268: Unix, AmigaOS, MS-DOS or OS/2,
6269:
6270: ! dir
6271:
6272: prints a directory listing and then returns to `gnuplot`.
6273:
6274: On an Atari, the `!` command first checks whether a shell is already loaded
6275: and uses it, if available. This is practical if `gnuplot` is run from
6276: `gulam`, for example.
6277: 2 splot
6278: ?commands splot
6279: ?splot
6280: `splot` is the command for drawing 3-d plots (well, actually projections on
6281: a 2-d surface, but you knew that). It can create a plot from functions or
6282: a data file in a manner very similar to the `plot` command.
6283:
6284: See `plot` for features common to the `plot` command; only differences are
6285: discussed in detail here. Note specifically that the `binary` and `matrix`
6286: options (discussed under "datafile-modifiers") are not available for `plot`.
6287:
6288: Syntax:
6289: splot {<ranges>}
6290: <function> | "<datafile>" {datafile-modifiers}}
6291: {<title-spec>} {with <style>}
6292: {, {definitions,} <function> ...}
6293:
6294: where either a <function> or the name of a data file enclosed in quotes is
6295: supplied. The function can be a mathematical expression, or a triple of
6296: mathematical expressions in parametric mode.
6297:
6298: By default `splot` draws the xy plane completely below the plotted data.
6299: The offset between the lowest ztic and the xy plane can be changed by `set
6300: ticslevel`. The orientation of a `splot` projection is controlled by
6301: `set view`. See `set view` and `set ticslevel` for more information.
6302:
6303: The syntax for setting ranges on the `splot` command is the same as for
6304: `plot`. In non-parametric mode, the order in which ranges must be given is
6305: `xrange`, `yrange`, and `zrange`. In parametric mode, the order is `urange`,
6306: `vrange`, `xrange`, `yrange`, and `zrange`.
6307:
6308: The `title` option is the same as in `plot`. The operation of `with` is also
6309: the same as in `plot`, except that the plotting styles available to `splot`
6310: are limited to `lines`, `points`, `linespoints`, `dots`, and `impulses`; the
6311: error-bar capabilities of `plot` are not available for `splot`.
6312:
6313: The datafile options have more differences.
6314: 3 data-file
6315: ?commands splot datafile
6316: ?splot datafile
6317: ?splot data-file
6318: As for `plot`, discrete data contained in a file can be displayed by
6319: specifying the name of the data file, enclosed in quotes, on the `splot`
6320: command line.
6321:
6322: Syntax:
6323: splot '<file_name>' {binary | matrix}
6324: {index <index list>}
6325: {every <every list>}
6326: {using <using list>}
6327:
6328: The special filenames `""` and `"-"` are permitted, as in `plot`.
6329:
6330: In brief, `binary` and `matrix` indicate that the the data are in a special
6331: form, `index` selects which data sets in a multi-data-set file are to be
6332: plotted, `every` specifies which datalines (subsets) within a single data
6333: set are to be plotted, and `using` determines how the columns within a single
6334: record are to be interpreted.
6335:
6336: The options `index` and `every` behave the same way as with `plot`; `using`
6337: does so also, except that the `using` list must provide three entries
6338: instead of two.
6339:
6340: The `plot` options `thru` and `smooth` are not available for `splot`, but
6341: `cntrparams` and `dgrid3d` provide limited smoothing cabilities.
6342:
6343: Data file organization is essentially the same as for `plot`, except that
6344: each point is an (x,y,z) triple. If only a single value is provided, it
6345: will be used for z, the datablock number will be used for y, and the index
6346: of the data point in the datablock will be used for x. If two values are
6347: provided, `gnuplot` gives you an error message. Three values are interpreted
6348: as an (x,y,z) triple. Additional values are generally used as errors, which
6349: can be used by `fit`.
6350:
6351: Single blank records separate datablocks in a `splot` datafile; `splot`
6352: treats datablocks as the equivalent of function y-isolines. No line will
6353: join points separated by a blank record. If all datablocks contain the same
6354: number of points, `gnuplot` will draw cross-isolines between datablocks,
6355: connecting corresponding points. This is termed "grid data", and is required
6356: for drawing a surface, for contouring (`set contour`) and hidden-line removal
6357: (`set hidden3d`). See also `splot grid data`
6358:
6359: It is no longer necessary to specify `parametric` mode for three-column
6360: `splot`s.
6361: 4 binary
6362: ?commands splot datafile binary
6363: ?splot datafile binary
6364: ?splot binary
6365: ?data-file binary
6366: ?datafile binary
6367: ?binary
6368: ?binary data
6369: ?binary files
6370: `splot` can read binary files written with a specific format (and on a
6371: system with a compatible binary file representation.)
6372:
6373: In previous versions, `gnuplot` dynamically detected binary data files. It
6374: is now necessary to specify the keyword `binary` directly after the filename.
6375:
6376: Single precision floats are stored in a binary file as follows:
6377:
6378: <N+1> <y0> <y1> <y2> ... <yN>
6379: <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
6380: <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
6381: : : : : ... :
6382:
6383: which are converted into triplets:
6384: <x0> <y0> <z0,0>
6385: <x0> <y1> <z0,1>
6386: <x0> <y2> <z0,2>
6387: : : :
6388: <x0> <yN> <z0,N>
6389:
6390: <x1> <y0> <z1,0>
6391: <x1> <y1> <z1,1>
6392: : : :
6393:
6394: These triplets are then converted into `gnuplot` iso-curves and then
6395: `gnuplot` proceeds in the usual manner to do the rest of the plotting.
6396:
6397: A collection of matrix and vector manipulation routines (in C) is provided
6398: in `binary.c`. The routine to write binary data is
6399:
6400: int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)
6401:
6402: An example of using these routines is provided in the file `bf_test.c`, which
6403: generates binary files for the demo file `demo/binary.dem`.
6404:
6405: The `index` keyword is not supported, since the file format allows only one
6406: surface per file. The `every` and `using` filters are supported. `using`
6407: operates as if the data were read in the above triplet form.
1.1.1.2 ! maekawa 6408: ^ <a href="http://www.gnuplot.vt.edu/gnuplot/gpdocs/binary.html">Binary File Splot Demo.</a>
1.1 maekawa 6409: 4 example datafile
6410: ?commands splot datafile example
6411: ?splot datafile example
6412: ?splot example
6413: A simple example of plotting a 3-d data file is
6414:
6415: splot 'datafile.dat'
6416:
6417: where the file "datafile.dat" might contain:
6418:
6419: # The valley of the Gnu.
6420: 0 0 10
6421: 0 1 10
6422: 0 2 10
6423:
6424: 1 0 10
6425: 1 1 5
6426: 1 2 10
6427:
6428: 2 0 10
6429: 2 1 1
6430: 2 2 10
6431:
6432: 3 0 10
6433: 3 1 0
6434: 3 2 10
6435:
6436: Note that "datafile.dat" defines a 4 by 3 grid ( 4 rows of 3 points each ).
6437: Rows (datablocks) are separated by blank records.
6438:
6439: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/splot.gif" alt="[splot.gif]" width=640 height=480>
6440: Note also that the x value is held constant within each dataline. If you
6441: instead keep y constant, and plot with hidden-line removal enabled, you will
6442: find that the surface is drawn 'inside-out'.
6443:
6444: Actually for grid data it is not necessary to keep the x values constant
6445: within a datablock, nor is it necessary to keep the same sequence of y
6446: values. `gnuplot` requires only that the number of points be the same for
6447: each datablock. However since the surface mesh, from which contours are
6448: derived, connects sequentially corresponding points, the effect of an
6449: irregular grid on a surface plot is unpredictable and should be examined
6450: on a case-by-case basis.
6451: 4 matrix
6452: ?commands splot datafile matrix
6453: ?splot datafile matrix
6454: ?splot matrix
6455: ?data-file matrix
6456: ?datafile matrix
6457: ?matrix
6458: The `matrix` flag indicates that the ASCII data are stored in matrix format.
6459: The z-values are read in a row at a time, i. e.,
6460: z11 z12 z13 z14 ...
6461: z21 z22 z23 z24 ...
6462: z31 z32 z33 z34 ...
6463: and so forth. The row and column indices are used for the x- and y-values.
6464: 3 grid_data
6465: ?commands splot grid_data
6466: ?splot grid_data
6467: ?grid_data
6468: The 3D routines are designed for points in a grid format, with one sample,
6469: datapoint, at each mesh intersection; the datapoints may originate from
6470: either evaluating a function, see `set isosamples`, or reading a datafile,
6471: see `splot datafile`. The term "isoline" is applied to the mesh lines for
6472: both functions and data. Note that the mesh need not be rectangular in x
6473: and y, as it may be parameterized in u and v, see `set isosamples`.
6474:
6475: However, `gnuplot` does not require that format. In the case of functions,
6476: 'samples' need not be equal to 'isosamples', i.e., not every x-isoline
6477: sample need intersect a y-isoline. In the case of data files, if there
6478: are an equal number of scattered data points in each datablock, then
6479: "isolines" will connect the points in a datablock, and "cross-isolines"
6480: will connect the corresponding points in each datablock to generate a
6481: "surface". In either case, contour and hidden3d modes may give different
6482: plots than if the points were in the intended format. Scattered data can be
6483: converted to a {different} grid format with `set dgrid3d`.
6484:
6485: The contour code tests for z intensity along a line between a point on a
6486: y-isoline and the corresponding point in the next y-isoline. Thus a `splot`
6487: contour of a surface with samples on the x-isolines that do not coincide with
6488: a y-isoline intersection will ignore such samples. Try:
6489: set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
6490: set function style lp
6491: set contour
6492: set isosamples 10,10; set samples 10,10;
6493: splot cos(x)*cos(y)
6494: set samples 4,10; replot
6495: set samples 10,4; replot
6496:
6497: 3 splot_overview
6498: ?commands splot_overview
6499: ? splot_overview
6500: `splot` can display a surface as a collection of points, or by connecting
6501: those points. As with `plot`, the points may be read from a data file or
6502: result from evaluation of a function at specified intervals, see `set
6503: isosamples`. The surface may be approximated by connecting the points
6504: with straight line segments, see `set surface`, in which case the surface
6505: can be made opaque with `set hidden3d.` The orientation from which the 3d
6506: surface is viewed can be changed with `set view`.
6507:
6508: Additionally, for points in a grid format, `splot` can interpolate points
6509: having a common amplitude (see `set contour`) and can then connect those
6510: new points to display contour lines, either directly with straight-line
6511: segments or smoothed lines (see `set cntrparams`). Functions are already
6512: evaluated in a grid format, determined by `set isosamples` and `set samples`,
6513: while file data must either be in a grid format, as described in `data-file`,
6514: or be used to generate a grid (see `set dgrid3d`).
6515:
6516: Contour lines may be displayed either on the surface or projected onto the
6517: base. The base projections of the contour lines may be written to a
6518: file, and then read with `plot`, to take advantage of `plot`'s additional
6519: formatting capabilities.
6520: 2 test
6521: ?commands test
6522: ?test
6523: `test` creates a display of line and point styles and other useful things
6524: appropriate for the terminal you are using.
6525:
6526: Syntax:
6527: test
6528: 2 update
6529: ?commands update
6530: ?update
6531: This command writes the current values of the fit parameters into the given
6532: file, formatted as an initial-value file (as described in the `fit`section).
6533: This is useful for saving the current values for later use or for restarting
6534: a converged or stopped fit.
6535:
6536: Syntax:
6537: update <filename> {<filename>}
6538:
6539: If a second filename is supplied, the updated values are written to this
6540: file, and the original parameter file is left unmodified.
6541:
6542: Otherwise, if the file already exists, `gnuplot` first renames it by
6543: appending `.old` and then opens a new file. That is, "`update 'fred'`"
6544: behaves the same as "`!rename fred fred.old; update 'fred.old' 'fred'`".
6545: [On DOS and other systems that use the twelve-character "filename.ext"
6546: naming convention, "ext" will be "`old`" and "filename" will be related
6547: (hopefully recognizably) to the initial name. Renaming is not done at all
6548: on VMS systems, since they use file-versioning.]
6549:
6550: Please see `fit` for more information.
6551: 1 Graphical User Interfaces
6552: ?graphical user interfaces
6553: ?gui's
6554: Several graphical user interfaces have been written for `gnuplot` and one for
6555: win32 is included in this distribution. In addition, there is a Macintosh
6556: interface at
6557: ^<a href="ftp://ftp.ee.gatech.edu/pub/mac/gnuplot">
6558: ftp://ftp.ee.gatech.edu/pub/mac/gnuplot
6559: ^</a>
6560: and several X11 interfaces include three Tcl/Tk located at the usual Tcl/Tk
6561: repositories.
6562: 1 Bugs
6563: ?bugs
6564: Floating point exceptions (floating point number too large/small, divide by
6565: zero, etc.) may occasionally be generated by user defined functions. Some of
6566: the demos in particular may cause numbers to exceed the floating point range.
6567: Whether the system ignores such exceptions (in which case `gnuplot` labels
6568: the corresponding point as undefined) or aborts `gnuplot` depends on the
6569: compiler/runtime environment.
6570:
6571: The bessel functions do not work for complex arguments.
6572:
6573: The gamma function does not work for complex arguments.
6574:
6575: As of `gnuplot` version 3.7, all development has been done using ANSI C.
6576: With current operating system, compiler, and library releases, the OS
6577: specific bugs documented in release 3.5, now relegated to `old_bugs`, may
6578: no longer be relevant.
6579:
6580: Bugs reported since the current release may be located via the official
6581: distribution site:
6582: ftp://ftp.dartmouth.edu/pub/gnuplot
6583: http://www.cs.dartmouth.edu/gnuplot_info.html
6584:
6585: Please e-mail any bugs to bug-gnuplot@dartmouth.edu.
6586: 2 Old_bugs
6587: ?old_bugs
6588: ?os_bugs
6589: There is a bug in the stdio library for old Sun operating systems (SunOS
6590: Sys4-3.2). The "%g" format for 'printf' sometimes incorrectly prints numbers
6591: (e.g., 200000.0 as "2"). Thus, tic mark labels may be incorrect on a Sun4
6592: version of `gnuplot`. A work-around is to rescale the data or use the `set
6593: format` command to change the tic mark format to "%7.0f" or some other
6594: appropriate format. This appears to have been fixed in SunOS 4.0.
6595:
6596: Another bug: On a Sun3 under SunOS 4.0, and on Sun4's under Sys4-3.2 and
6597: SunOS 4.0, the 'sscanf' routine incorrectly parses "00 12" with the format
6598: "%f %f" and reads 0 and 0 instead of 0 and 12. This affects data input. If
6599: the data file contains x coordinates that are zero but are specified like
6600: '00', '000', etc, then you will read the wrong y values. Check any data
6601: files or upgrade the SunOS. It appears to have been fixed in SunOS 4.1.1.
6602:
6603: Suns appear to overflow when calculating exp(-x) for large x, so `gnuplot`
6604: gets an undefined result. One work-around is to make a user-defined function
6605: like e(x) = x<-500 ? 0 : exp(x). This affects plots of Gaussians (exp(-x*x))
6606: in particular, since x*x grows quite rapidly.
6607:
6608: Microsoft C 5.1 has a nasty bug associated with the %g format for 'printf'.
6609: When any of the formats "%.2g", "%.1g", "%.0g", "%.g" are used, 'printf' will
6610: incorrectly print numbers in the range 1e-4 to 1e-1. Numbers that should be
6611: printed in the %e format are incorrectly printed in the %f format, with the
6612: wrong number of zeros after the decimal point. To work around this problem,
6613: use the %e or %f formats explicitly.
6614:
6615: `gnuplot`, when compiled with Microsoft C, did not work correctly on two VGA
6616: displays that were tested. The CGA, EGA and VGA drivers should probably be
6617: rewritten to use the Microsoft C graphics library. `gnuplot` compiled with
6618: Borland C++ uses the Turbo C graphics drivers and does work correctly with
6619: VGA displays.
6620:
6621: VAX/VMS 4.7 C compiler release 2.4 also has a poorly implemented %g format
6622: for 'printf'. The numbers are printed numerically correct, but may not be in
6623: the requested format. The K&R second edition says that for the %g format, %e
6624: is used if the exponent is less than -4 or greater than or equal to the
6625: precision. The VAX uses %e format if the exponent is less than -1. The VAX
6626: appears to take no notice of the precision when deciding whether to use %e or
6627: %f for numbers less than 1. To work around this problem, use the %e or %f
6628: formats explicitly. From the VAX C 2.4 release notes: e,E,f,F,g,G Result
6629: will always contain a decimal point. For g and G, trailing zeros will not
6630: be removed from the result.
6631:
6632: VAX/VMS 5.2 C compiler release 3.0 has a slightly better implemented %g
6633: format than release 2.4, but not much. Trailing decimal points are now
6634: removed, but trailing zeros are still not removed from %g numbers in
6635: exponential format.
6636:
6637: The two preceding problems are actually in the libraries rather than in the
6638: compilers. Thus the problems will occur whether `gnuplot` is built using
6639: either the DEC compiler or some other one (e.g. the latest gcc).
6640:
6641: ULTRIX X11R3 has a bug that causes the X11 driver to display "every other"
6642: graph. The bug seems to be fixed in DEC's release of X11R4 so newer releases
6643: of ULTRIX don't seem to have the problem. Solutions for older sites include
6644: upgrading the X11 libraries (from DEC or direct from MIT) or defining
6645: ULTRIX_KLUDGE when compiling the x11.trm file. Note that the kludge is not
6646: an ideal fix, however.
6647:
6648: The constant HUGE was incorrectly defined in the NeXT OS 2.0 operating
6649: system. HUGE should be set to 1e38 in plot.h. This error has been corrected
6650: in the 2.1 version of NeXT OS.
6651:
6652: Some older models of HP plotters do not have a page eject command 'PG'. The
6653: current HPGL driver uses this command in HPGL_reset. This may need to be
6654: removed for these plotters. The current PCL5 driver uses HPGL/2 for text as
6655: well as graphics. This should be modified to use scalable PCL fonts.
6656:
6657: On the Atari version, it is not possible to send output directly to the
6658: printer (using `/dev/lp` as output file), since CRs are added to LFs in
6659: binary output. As a work-around, write the output to a file and copy it to
6660: the printer afterwards using a shell command.
6661:
6662: On AIX 4, the literal 'NaNq' in a datafile causes the special internal value
6663: 'not-a-number' to be stored, rather than setting an internal 'undefined'
6664: flag. A workaround is to use `set missing 'NaNq'`.
6665:
6666: There may be an up-to-date list of bugs since the release on the WWW page:
6667: http://www.cs.dartmouth.edu/gnuplot_info.html
6668:
6669: Please report any bugs to bug-gnuplot@dartmouth.edu.
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