Annotation of OpenXM_contrib/gnuplot/docs/gnuplot.doc, Revision 1.1.1.1
1.1 maekawa 1: C RCS $Id: gnuplot.doc,v 1.64 1998/06/18 14:59:14 ddenholm Exp $
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`).
132: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/simple/simple.html"> Simple Plots Demo </a>
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
161: ^ <a href="http://www.uni-karlsruhe.de/~ig25/gnuplot-faq.html">
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
166: ftp://ftp.dartmouth.edu/pub/gnuplot
167: or see the WWW `gnuplot` page.
168:
169: When posting a question, please include full details of the version of
170: `gnuplot`, the machine, and operating system you are using. A _small_ script
171: demonstrating the problem may be useful. Function plots are preferable to
172: datafile plots. If email-ing to info-gnuplot, please state whether or not
173: you are subscribed to the list, so that users who use news will know to email
174: a reply to you. There is a form for such postings on the WWW site.
175: 2 What's New in version 3.7
176: ?new-features
177: Gnuplot version 3.7 contains many new features. This section gives a partial
178: list and links to the new items in no particular order.
179:
180: 1. `fit f(x) 'file' via` uses the Marquardt-Levenberg method to fit data.
181: (This is only slightly different from the `gnufit` patch available for 3.5.)
182:
183: 2. Greatly expanded `using` command. See `plot using`.
184:
185: 3. `set timefmt` allows for the use of dates as input and output for time
186: series plots. See `Time/Date data` and
187: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/timefmt/timefmt.html">
188: timedat.dem.
189: ^ </a>
190:
191: 4. Multiline labels and font selection in some drivers.
192:
193: 5. Minor (unlabeled) tics. See `set mxtics`.
194:
195: 6. `key` options for moving the key box in the page (and even outside of the
196: plot), putting a title on it and a box around it, and more. See `set key`.
197:
198: 7. Multiplots on a single logical page with `set multiplot`.
199:
200: 8. Enhanced `postscript` driver with super/subscripts and font changes.
201: (This was a separate driver (`enhpost`) that was available as a patch for
202: 3.5.)
203:
204: 9. Second axes: use the top and right axes independently of the bottom and
205: left, both for plotting and labels. See `plot`.
206:
207: 10. Special datafile names `'-'` and `""`. See `plot special-filenames`.
208:
209: 11. Additional coordinate systems for labels and arrows. See `coordinates`.
210:
211: 12. `set size` can try to plot with a specified aspect ratio.
212:
213: 13. `set missing` now treats missing data correctly.
214:
215: 14. The `call` command: `load` with arguments.
216:
217: 15. More flexible `range` commands with `reverse` and `writeback` keywords.
218:
219: 16. `set encoding` for multi-lingual encoding.
220:
221: 17. New `x11` driver with persistent and multiple windows.
222:
223: 18. New plotting styles: `xerrorbars`, `histeps`, `financebars` and more.
224: See `set style`.
225:
226: 19. New tic label formats, including `"%l %L"` which uses the mantissa and
227: exponents to a given base for labels. See `set format`.
228:
229: 20. New drivers, including `cgm` for inclusion into MS-Office applications
230: and `gif` for serving plots to the WEB.
231:
232: 21. Smoothing and spline-fitting options for `plot`. See `plot smooth`.
233:
234: 22. `set margin` and `set origin` give much better control over where a
235: graph appears on the page.
236:
237: 23. `set border` now controls each border individually.
238:
239: 24. The new commands `if` and `reread` allow command loops.
240:
241: 25. Point styles and sizes, line types and widths can be specified on the
242: `plot` command. Line types and widths can also be specified for grids,
243: borders, tics and arrows. See `plot with`. Furthermore these types may be
244: combined and stored for further use. See `set linestyle`.
245:
246: 26. Text (labels, tic labels, and the time stamp) can be written vertically
247: by those terminals capable of doing so.
248: 2 Batch/Interactive Operation
249: ?batch/interactive
250: `gnuplot` may be executed in either batch or interactive modes, and the two
251: may even be mixed together on many systems.
252:
253: Any command-line arguments are assumed to be names of files containing
254: `gnuplot` commands (with the exception of standard X11 arguments, which are
255: processed first). Each file is loaded with the `load` command, in the order
256: specified. `gnuplot` exits after the last file is processed. When no load
257: files are named, `gnuplot` enters into an interactive mode. The special
258: filename "-" is used to denote standard input.
259:
260: Both the `exit` and `quit` commands terminate the current command file and
261: `load` the next one, until all have been processed.
262:
263: Examples:
264:
265: To launch an interactive session:
266: gnuplot
267:
268: To launch a batch session using two command files "input1" and "input2":
269: gnuplot input1 input2
270:
271: To launch an interactive session after an initialization file "header" and
272: followed by another command file "trailer":
273: gnuplot header - trailer
274: 2 Command-line-editing
275: ?line-editing
276: ?editing
277: ?history
278: ?command-line-editing
279: Command-line editing is supported by the Unix, Atari, VMS, MS-DOS and OS/2
280: versions of `gnuplot`. Also, a history mechanism allows previous commands to
281: be edited and re-executed. After the command line has been edited, a newline
282: or carriage return will enter the entire line without regard to where the
283: cursor is positioned.
284:
285: (The readline function in `gnuplot` is not the same as the readline used in
286: GNU Bash and GNU Emacs. If the GNU version is desired, it may be selected
287: instead of the `gnuplot` version at compile time.)
288:
289:
290: The editing commands are as follows:
291:
292: @start table - first is interactive cleartext form
293: `Line-editing`:
294:
295: ^B moves back a single character.
296: ^F moves forward a single character.
297: ^A moves to the beginning of the line.
298: ^E moves to the end of the line.
299: ^H and DEL delete the previous character.
300: ^D deletes the current character.
301: ^K deletes from current position to the end of line.
302: ^L,^R redraws line in case it gets trashed.
303: ^U deletes the entire line.
304: ^W deletes the last word.
305:
306: `History`:
307:
308: ^P moves back through history.
309: ^N moves forward through history.
310: #\begin{tabular}{|cl|} \hline
311: #\multicolumn{2}{|c|}{Command-line Editing Commands} \\ \hline \hline
312: #Character & Function \\ \hline
313: # & \multicolumn{1}{|c|}{Line Editing}\\ \cline{2-2}
314: #\verb~^B~ & move back a single character.\\
315: #\verb~^F~ & move forward a single character.\\
316: #\verb~^A~ & move to the beginning of the line.\\
317: #\verb~^E~ & move to the end of the line.\\
318: #\verb~^H, DEL~ & delete the previous character.\\
319: #\verb~^D~ & delete the current character.\\
320: #\verb~^K~ & delete from current position to the end of line.\\
321: #\verb~^L, ^R~ & redraw line in case it gets trashed.\\
322: #\verb~^U~ & delete the entire line. \\
323: #\verb~^W~ & delete from the current word to the end of line. \\ \hline
324: # & \multicolumn{1}{|c|}{History} \\ \cline{2-2}
325: #\verb~^P~ & move back through history.\\
326: #\verb~^N~ & move forward through history.\\
327: %c l .
328: %Character@Function
329: %_
330: %@Line Editing
331: %^B@move back a single character.
332: %^F@move forward a single character.
333: %^A@move to the beginning of the line.
334: %^E@move to the end of the line.
335: %^H, DEL@delete the previous character.
336: %^D@delete the current character.
337: %^K@delete from current position to the end of line.
338: %^L, ^R@redraw line in case it gets trashed.
339: %^U@delete the entire line.
340: %^W@delete from the current word to the end of line.
341: %_
342: %@History
343: %^P@move back through history.
344: %^N@move forward through history.
345: @end table
346:
347: On the IBM PC, the use of a TSR program such as DOSEDIT or CED may be desired
348: for line editing. The default makefile assumes that this is the case; by
349: default `gnuplot` will be compiled with no line-editing capability. If you
350: want to use `gnuplot`'s line editing, set READLINE in the makefile and add
351: readline.obj to the link file. The following arrow keys may be used on the
352: IBM PC and Atari versions if readline is used:
353:
354: @start table - first is interactive cleartext form
355: Left Arrow - same as ^B.
356: Right Arrow - same as ^F.
357: Ctrl Left Arrow - same as ^A.
358: Ctrl Right Arrow - same as ^E.
359: Up Arrow - same as ^P.
360: Down Arrow - same as ^N.
361: #\begin{tabular}{|cl|} \hline
362: #Arrow key & Function \\ \hline
363: #Left & same as \verb~^B~. \\
364: #Right & same as \verb~^F~. \\
365: #Ctrl Left & same as \verb~^A~. \\
366: #Ctrl Right & same as \verb~^E~. \\
367: #Up & same as \verb~^P~. \\
368: #Down & same as \verb~^N~. \\
369: %c l .
370: %Arrow key@Function
371: %_
372: %Left Arrow@same as ^B.
373: %Right Arrow@same as ^F.
374: %Ctrl Left Arrow@same as ^A.
375: %Ctrl Right Arrow@same as ^E.
376: %Up Arrow@same as ^P.
377: %Down Arrow@same as ^N.
378: %_
379: @end table
380:
381: The Atari version of readline defines some additional key aliases:
382:
383: @start table - first is interactive cleartext form
384: Undo - same as ^L.
385: Home - same as ^A.
386: Ctrl Home - same as ^E.
387: Esc - same as ^U.
388: Help - `help` plus return.
389: Ctrl Help - `help `.
390: #\begin{tabular}{|cl|} \hline
391: #Arrow key & Function \\ \hline
392: #Undo & same as \verb~^L~. \\
393: #Home & same as \verb~^A~. \\
394: #Ctrl Home & same as \verb~^E~. \\
395: #Esc & same as \verb~^U~. \\
396: #Help & `{\bf help}' plus return. \\
397: #Ctrl Help & `{\bf help }'. \\
398: %c l .
399: %Arrow key@Function
400: %_
401: %Undo@same as ^L.
402: %Home@same as ^A.
403: %Ctrl Home@same as ^E.
404: %Esc@same as ^U.
405: %Help@help plus return.
406: %Ctrl Help@help .
407: %_
408: @end table
409: 2 Comments
410: ?comments
411: Comments are supported as follows: a `#` may appear in most places in a line
412: and `gnuplot` will ignore the rest of the line. It will not have this effect
413: inside quotes, inside numbers (including complex numbers), inside command
414: substitutions, etc. In short, it works anywhere it makes sense to work.
415: 2 Coordinates
416: ?coordinates
417: The commands `set arrow`, `set key`, and `set label` allow you to draw
418: something at an arbitrary position on the graph. This position is specified
419: by the syntax:
420:
421: {<system>} <x>, {<system>} <y> {,{<system>} <z>}
422:
423: Each <system> can either be `first`, `second`, `graph` or `screen`.
424:
425: `first` places the x, y, or z coordinate in the system defined by the left
426: and bottom axes; `second` places it in the system defined by the second axes
427: (top and right); `graph` specifies the area within the axes---0,0 is bottom
428: left and 1,1 is top right (for splot, 0,0,0 is bottom left of plotting area;
429: use negative z to get to the base---see `set ticslevel`); and `screen`
430: specifies the screen area (the entire area---not just the portion selected by
431: `set size`), with 0,0 at bottom left and 1,1 at top right.
432:
433: If the coordinate system for x is not specified, `first` is used. If the
434: system for y is not specified, the one used for x is adopted.
435:
436: If one (or more) axis is timeseries, the appropriate coordinate should
437: be given as a quoted time string according to the `timefmt` format string.
438: See `set xdata` and `set timefmt`. `gnuplot` will also accept an integer
439: expression, which will be interpreted as seconds from 1 January 2000.
440: 2 Environment
441: ?environment
442: A number of shell environment variables are understood by `gnuplot`. None of
443: these are required, but may be useful.
444:
445: If GNUTERM is defined, it is used as the name of the terminal type to be
446: used. This overrides any terminal type sensed by `gnuplot` on start-up, but
447: is itself overridden by the .gnuplot (or equivalent) start-up file (see
448: `start-up`) and, of course, by later explicit changes.
449:
450: On Unix, AmigaOS, AtariTOS, MS-DOS and OS/2, GNUHELP may be defined to be the
451: pathname of the HELP file (gnuplot.gih).
452:
453: On VMS, the logical name GNUPLOT$HELP should be defined as the name of the
454: help library for `gnuplot`. The `gnuplot` help can be put inside any system
455: help library, allowing access to help from both within and outside `gnuplot`
456: if desired.
457:
458: On Unix, HOME is used as the name of a directory to search for a .gnuplot
459: file if none is found in the current directory. On AmigaOS, AtariTOS,
460: MS-DOS and OS/2, gnuplot is used. On VMS, SYS$LOGIN: is used. See `help
461: start-up`.
462:
463: On Unix, PAGER is used as an output filter for help messages.
464:
465: On Unix, AtariTOS and AmigaOS, SHELL is used for the `shell` command. On
466: MS-DOS and OS/2, COMSPEC is used for the `shell` command.
467:
468: On MS-DOS, if the BGI or Watcom interface is used, PCTRM is used to tell
469: the maximum resolution supported by your monitor by setting it to
470: S<max. horizontal resolution>. E.g. if your monitor's maximum resolution is
471: 800x600, then use:
472: set PCTRM=S800
473: If PCTRM is not set, standard VGA is used.
474:
475: FIT_SCRIPT may be used to specify a `gnuplot` command to be executed when a
476: fit is interrupted---see `fit`. FIT_LOG specifies the filename of the
477: logfile maintained by fit.
478: 2 Expressions
479: ?expressions
480: In general, any mathematical expression accepted by C, FORTRAN, Pascal, or
481: BASIC is valid. The precedence of these operators is determined by the
482: specifications of the C programming language. White space (spaces and tabs)
483: is ignored inside expressions.
484:
485: Complex constants are expressed as {<real>,<imag>}, where <real> and <imag>
486: must be numerical constants. For example, {3,2} represents 3 + 2i; {0,1}
487: represents 'i' itself. The curly braces are explicitly required here.
488:
489: Note that gnuplot uses both "real" and "integer" arithmetic, like FORTRAN and
490: C. Integers are entered as "1", "-10", etc; reals as "1.0", "-10.0", "1e1",
491: 3.5e-1, etc. The most important difference between the two forms is in
492: division: division of integers truncates: 5/2 = 2; division of reals does
493: not: 5.0/2.0 = 2.5. In mixed expressions, integers are "promoted" to reals
494: before evaluation: 5/2e0 = 2.5. The result of division of a negative integer
495: by a positive one may vary among compilers. Try a test like "print -5/2" to
496: determine if your system chooses -2 or -3 as the answer.
497:
498: The integer expression "1/0" may be used to generate an "undefined" flag,
499: which causes a point to ignored; the `ternary` operator gives an example.
500:
501: The real and imaginary parts of complex expressions are always real, whatever
502: the form in which they are entered: in {3,2} the "3" and "2" are reals, not
503: integers.
504: 3 Functions
505: ?expressions functions
506: ?functions
507: The functions in `gnuplot` are the same as the corresponding functions in
508: the Unix math library, except that all functions accept integer, real, and
509: complex arguments, unless otherwise noted.
510:
511: For those functions that accept or return angles that may be given in either
512: degrees or radians (sin(x), cos(x), tan(x), asin(x), acos(x), atan(x),
513: atan2(x) and arg(z)), the unit may be selected by `set angles`, which
514: defaults to radians.
515:
516: @start table
517: #\begin{tabular}{|ccl|} \hline
518: #\multicolumn{3}{|c|}{Math library functions} \\ \hline \hline
519: #Function & Arguments & Returns \\ \hline
520: %c c l .
521: %Function@Arguments@Returns
522: %_
523: 4 abs
524: ?expressions functions abs
525: ?functions abs
526: ?abs
527: #abs(x) & any & absolute value of $x$, $|x|$; same type \\
528: #abs(x) & complex & length of $x$, $\sqrt{{\mbox{real}(x)^{2} +
529: #\mbox{imag}(x)^{2}}}$ \\
530: %abs(x)@any@absolute value of $x$, $|x|$; same type
531: %abs(x)@complex@length of $x$, $sqrt{roman real (x) sup 2 + roman imag (x) sup 2}$
532: The `abs` function returns the absolute value of its argument. The returned
533: value is of the same type as the argument.
534:
535: For complex arguments, abs(x) is defined as the length of x in the complex
536: plane [i.e., sqrt(real(x)**2 + imag(x)**2) ].
537: 4 acos
538: ?expressions functions acos
539: ?functions acos
540: ?acos
541: #acos(x) & any & $\cos^{-1} x$ (inverse cosine) \\
542: %acos(x)@any@$cos sup -1 x$ (inverse cosine)
543: The `acos` function returns the arc cosine (inverse cosine) of its argument.
544: `acos` returns its argument in radians or degrees, as selected by `set
545: angles`.
546: 4 acosh
547: ?expressions functions acosh
548: ?functions acosh
549: ?acosh
550: #acosh(x) & any & $\cosh^{-1} x$ (inverse hyperbolic cosine) in radians \\
551: %acosh(x)@any@$cosh sup -1 x$ (inverse hyperbolic cosine) in radians
552: The `acosh` function returns the inverse hyperbolic cosine of its argument in
553: radians.
554: 4 arg
555: ?expressions functions arg
556: ?functions arg
557: ?arg
558: #arg(x) & complex & the phase of $x$ \\
559: %arg(x)@complex@the phase of $x$
560: The `arg` function returns the phase of a complex number in radians or
561: degrees, as selected by `set angles`.
562: 4 asin
563: ?expressions functions asin
564: ?functions asin
565: ?asin
566: #asin(x) & any & $\sin^{-1} x$ (inverse sin) \\
567: %asin(x)@any@$sin sup -1 x$ (inverse sin)
568: The `asin` function returns the arc sin (inverse sin) of its argument.
569: `asin` returns its argument in radians or degrees, as selected by `set
570: angles`.
571: 4 asinh
572: ?expressions functions asinh
573: ?functions asinh
574: ?asinh
575: #asinh(x) & any & $\sinh^{-1} x$ (inverse hyperbolic sin) in radians \\
576: %asinh(x)@any@$sinh sup -1 x$ (inverse hyperbolic sin) in radians
577: The `asinh` function returns the inverse hyperbolic sin of its argument in
578: radians.
579: 4 atan
580: ?expressions functions atan
581: ?functions atan
582: ?atan
583: #atan(x) & any & $\tan^{-1} x$ (inverse tangent) \\
584: %atan(x)@any@$tan sup -1 x$ (inverse tangent)
585: The `atan` function returns the arc tangent (inverse tangent) of its
586: argument. `atan` returns its argument in radians or degrees, as selected by
587: `set angles`.
588: 4 atan2
589: ?expressions functions atan2
590: ?functions atan2
591: ?atan2
592: #atan2(y,x) & int or real & $\tan^{-1} (y/x)$ (inverse tangent) \\
593: %atan2(y,x)@int or real@$tan sup -1 (y/x)$ (inverse tangent)
594: The `atan2` function returns the arc tangent (inverse tangent) of the ratio
595: of the real parts of its arguments. `atan2` returns its argument in radians
596: or degrees, as selected by `set angles`, in the correct quadrant.
597: 4 atanh
598: ?expressions functions atanh
599: ?functions atanh
600: ?atan
601: #atanh(x) & any & $\tanh^{-1} x$ (inverse hyperbolic tangent) in radians \\
602: %atanh(x)@any@$tanh sup -1 x$ (inverse hyperbolic tangent) in radians
603: The `atanh` function returns the inverse hyperbolic tangent of its argument
604: in radians.
605: 4 besj0
606: ?expressions functions besj0
607: ?functions besj0
608: ?besj0
609: #besj0(x) & int or real & $j_{0}$ Bessel function of $x$, in radians \\
610: %besj0(x)@int or real@$j sub 0$ Bessel function of $x$, in radians
611: The `besj0` function returns the j0th Bessel function of its argument.
612: `besj0` expects its argument to be in radians.
613: 4 besj1
614: ?expressions functions besj1
615: ?functions besj1
616: ?besj1
617: #besj1(x) & int or real & $j_{1}$ Bessel function of $x$, in radians \\
618: %besj1(x)@int or real@$j sub 1$ Bessel function of $x$, in radians
619: The `besj1` function returns the j1st Bessel function of its argument.
620: `besj1` expects its argument to be in radians.
621: 4 besy0
622: ?expressions functions besy0
623: ?functions besy0
624: ?besy0
625: #besy0(x) & int or real & $y_{0}$ Bessel function of $x$, in radians \\
626: %besy0(x)@int or real@$y sub 0$ Bessel function of $x$, in radians
627: The `besy0` function returns the y0th Bessel function of its argument.
628: `besy0` expects its argument to be in radians.
629: 4 besy1
630: ?expressions functions besy1
631: ?functions besy1
632: ?besy1
633: #besy1(x) & int or real & $y_{1}$ Bessel function of $x$, in radians \\
634: %besy1(x)@int or real@$y sub 1$ Bessel function of $x$, in radians
635: The `besy1` function returns the y1st Bessel function of its argument.
636: `besy1` expects its argument to be in radians.
637: 4 ceil
638: ?expressions functions ceil
639: ?functions ceil
640: ?ceil
641: #ceil(x) & any & $\lceil x \rceil$, smallest integer not less than $x$
642: #(real part) \\
643: %ceil(x)@any@$left ceiling x right ceiling$, smallest integer not less than $x$ (real part)
644: The `ceil` function returns the smallest integer that is not less than its
645: argument. For complex numbers, `ceil` returns the smallest integer not less
646: than the real part of its argument.
647: 4 cos
648: ?expressions functions cos
649: ?functions cos
650: ?cos
651: #cos(x) & any & $\cos x$, cosine of $x$ \\
652: %cos(x)@radians@$cos~x$, cosine of $x$
653: The `cos` function returns the cosine of its argument. `cos` accepts its
654: argument in radians or degrees, as selected by `set angles`.
655: 4 cosh
656: ?expressions functions cosh
657: ?functions cosh
658: ?cosh
659: #cosh(x) & any & $\cosh x$, hyperbolic cosine of $x$ in radians \\
660: %cosh(x)@any@$cosh~x$, hyperbolic cosine of $x$ in radians
661: The `cosh` function returns the hyperbolic cosine of its argument. `cosh`
662: expects its argument to be in radians.
663: 4 erf
664: ?expressions functions erf
665: ?functions erf
666: ?erf
667: #erf(x) & any & $\mbox{erf}(\mbox{real}(x))$, error function of real($x$) \\
668: %erf(x)@any@$erf ( roman real (x))$, error function of real ($x$)
669: The `erf` function returns the error function of the real part of its
670: argument. If the argument is a complex value, the imaginary component is
671: ignored.
672: 4 erfc
673: ?expressions functions erfc
674: ?functions erfc
675: ?erfc
676: #erfc(x) & any & $\mbox{erfc}(\mbox{real}(x))$, 1.0 - error function of real($x$) \\
677: %erfc(x)@any@$erfc ( roman real (x))$, 1.0 - error function of real ($x$)
678: The `erfc` function returns 1.0 - the error function of the real part of its
679: argument. If the argument is a complex value, the imaginary component is
680: ignored.
681: 4 exp
682: ?expressions functions exp
683: ?functions exp
684: ?exp
685: #exp(x) & any & $e^{x}$, exponential function of $x$ \\
686: %exp(x)@any@$e sup x$, exponential function of $x$
687: The `exp` function returns the exponential function of its argument (`e`
688: raised to the power of its argument). On some implementations (notably
689: suns), exp(-x) returns undefined for very large x. A user-defined function
690: like safe(x) = x<-100 ? 0 : exp(x) might prove useful in these cases.
691: 4 floor
692: ?expressions functions floor
693: ?functions floor
694: ?floor
695: #floor(x) & any & $\lfloor x \rfloor$, largest integer not greater
696: #than $x$ (real part) \\
697: %floor(x)@any@$left floor x right floor$, largest integer not greater than $x$ (real part)
698: The `floor` function returns the largest integer not greater than its
699: argument. For complex numbers, `floor` returns the largest integer not
700: greater than the real part of its argument.
701: 4 gamma
702: ?expressions functions gamma
703: ?functions gamma
704: ?gamma
705: #gamma(x) & any & $\mbox{gamma}(\mbox{real}(x))$, gamma function of real($x$) \\
706: %gamma(x)@any@$GAMMA ( roman real (x))$, gamma function of real ($x$)
707: The `gamma` function returns the gamma function of the real part of its
708: argument. For integer n, gamma(n+1) = n!. If the argument is a complex
709: value, the imaginary component is ignored.
710: 4 ibeta
711: ?expressions functions ibeta
712: ?functions ibeta
713: ?ibeta
714: #ibeta(p,q,x) & any & $\mbox{ibeta}(\mbox{real}(p,q,x))$, ibeta function of real($p$,$q$,$x$) \\
715: %ibeta(p,q,x)@any@$ibeta ( roman real (p,q,x))$, ibeta function of real ($p$,$q$,$x$)
716: The `ibeta` function returns the incomplete beta function of the real parts
717: of its arguments. p, q > 0 and x in [0:1]. If the arguments are complex,
718: the imaginary components are ignored.
719: 4 inverf
720: ?expressions functions inverf
721: ?functions inverf
722: ?inverf
723: #inverf(x) & any & inverse error function of real($x$) \\
724: %inverf(x)@any@inverse error function real($x$)
725: The `inverf` function returns the inverse error function of the real part
726: of its argument.
727: 4 igamma
728: ?expressions functions igamma
729: ?functions igamma
730: ?igamma
731: #igamma(a,x) & any & $\mbox{igamma}(\mbox{real}(a,x))$, igamma function of real($a$,$x$) \\
732: %igamma(a,x)@any@$igamma ( roman real (a,x))$, igamma function of real ($a$,$x$)
733: The `igamma` function returns the incomplete gamma function of the real
734: parts of its arguments. a > 0 and x >= 0. If the arguments are complex,
735: the imaginary components are ignored.
736: 4 imag
737: ?expressions functions imag
738: ?functions imag
739: ?imag
740: #imag(x) & complex & imaginary part of $x$ as a real number \\
741: %imag(x)@complex@imaginary part of $x$ as a real number
742: The `imag` function returns the imaginary part of its argument as a real
743: number.
744: 4 invnorm
745: ?expressions functions invnorm
746: ?functions invnorm
747: ?invnorm
748: #invnorm(x) & any & inverse normal distribution function of real($x$) \\
749: %invnorm(x)@any@inverse normal distribution function real($x$)
750: The `invnorm` function returns the inverse normal distribution function of
751: the real part of its argument.
752: 4 int
753: ?expressions functions int
754: ?functions int
755: ?int
756: #int(x) & real & integer part of $x$, truncated toward zero \\
757: %int(x)@real@integer part of $x$, truncated toward zero
758: The `int` function returns the integer part of its argument, truncated
759: toward zero.
760: 4 lgamma
761: ?expressions functions lgamma
762: ?functions lgamma
763: ?lgamma
764: #lgamma(x) & any & $\mbox{lgamma}(\mbox{real}(x))$, lgamma function of real($x$) \\
765: %lgamma(x)@any@$lgamma ( roman real (x))$, lgamma function of real ($x$)
766: The `lgamma` function returns the natural logarithm of the gamma function
767: of the real part of its argument. If the argument is a complex value, the
768: imaginary component is ignored.
769: 4 log
770: ?expressions functions log
771: ?functions log
772: ?log
773: #log(x) & any & $\log_{e} x$, natural logarithm (base $e$) of $x$ \\
774: %log(x)@any@$ln~x$, natural logarithm (base $e$) of $x$
775: The `log` function returns the natural logarithm (base `e`) of its argument.
776: 4 log10
777: ?expressions functions log10
778: ?functions log10
779: ?log10
780: #log10(x) & any & $\log_{10} x$, logarithm (base $10$) of $x$ \\
781: %log10(x)@any@${log sub 10}~x$, logarithm (base $10$) of $x$
782: The `log10` function returns the logarithm (base 10) of its argument.
783: 4 norm
784: ?expressions functions norm
785: ?functions norm
786: ?norm
787: #norm(x) & any & normal distribution (Gaussian) function of real($x$) \\
788: %norm(x)@any@$norm(x)$, normal distribution function of real($x$)
789: The `norm` function returns the normal distribution function (or Gaussian)
790: of the real part of its argument.
791: 4 rand
792: ?expressions functions rand
793: ?functions rand
794: ?rand
795: #rand(x) & any & $\mbox{rand}(\mbox{real}(x))$, pseudo random number generator \\
796: %rand(x)@any@$rand ( roman real (x))$, pseudo random number generator
797: The `rand` function returns a pseudo random number in the interval [0:1]
798: using the real part of its argument as a seed. If seed < 0, the sequence
799: is (re)initialized. If the argument is a complex value, the imaginary
800: component is ignored.
801: 4 real
802: ?expressions functions real
803: ?functions real
804: ?real
805: #real(x) & any & real part of $x$ \\
806: %real(x)@any@real part of $x$
807: The `real` function returns the real part of its argument.
808: 4 sgn
809: ?expressions functions sgn
810: ?functions sgn
811: ?sgn
812: #sgn(x) & any & 1 if $x>0$, -1 if $x<0$, 0 if $x=0$. imag($x$) ignored \\
813: %sgn(x)@any@1 if $x > 0$, -1 if $x < 0$, 0 if $x = 0$. $roman imag (x)$ ignored
814: The `sgn` function returns 1 if its argument is positive, -1 if its argument
815: is negative, and 0 if its argument is 0. If the argument is a complex value,
816: the imaginary component is ignored.
817: 4 sin
818: ?expressions functions sin
819: ?functions sin
820: ?sin
821: #sin(x) & any & $\sin x$, sine of $x$ \\
822: %sin(x)@any@$sin~x$, sine of $x$
823: The `sin` function returns the sine of its argument. `sin` expects its
824: argument to be in radians or degrees, as selected by `set angles`.
825: 4 sinh
826: ?expressions functions sinh
827: ?functions sinh
828: ?sinh
829: #sinh(x) & any & $\sinh x$, hyperbolic sine $x$ in radians \\
830: %sinh(x)@any@$sinh~x$, hyperbolic sine $x$ in radians
831: The `sinh` function returns the hyperbolic sine of its argument. `sinh`
832: expects its argument to be in radians.
833: 4 sqrt
834: ?expressions functions sqrt
835: ?functions sqrt
836: ?sqrt
837: #sqrt(x) & any & $\sqrt{x}$, square root of $x$ \\
838: %sqrt(x)@any@$sqrt x $, square root of $x$
839: The `sqrt` function returns the square root of its argument.
840: 4 tan
841: ?expressions functions tan
842: ?functions tan
843: ?tan
844: #tan(x) & any & $\tan x$, tangent of $x$ \\
845: %tan(x)@any@$tan~x$, tangent of $x$
846: The `tan` function returns the tangent of its argument. `tan` expects
847: its argument to be in radians or degrees, as selected by `set angles`.
848: 4 tanh
849: ?expressions functions tanh
850: ?functions tanh
851: ?tanh
852: #tanh(x) & any & $\tanh x$, hyperbolic tangent of $x$ in radians\\
853: %tanh(x)@any@$tanh~x$, hyperbolic tangent of $x$ in radians
854: The `tanh` function returns the hyperbolic tangent of its argument. `tanh`
855: expects its argument to be in radians.
856: @end table
857:
858: A few additional functions are also available.
859:
860: @start table
861: #\begin{tabular}{|ccl|} \hline
862: #\multicolumn{3}{|c|}{other {\bf gnuplot} functions} \\ \hline \hline
863: #Function & Arguments & Returns \\ \hline
864: %c c l .
865: %Function@Arguments@Returns
866: %_
867: 4 column
868: ?expressions functions column
869: ?functions column
870: ?column
871: #column(x) & int & column $x$ during datafile manipulation. \\
872: %column(x)@int@ column $x$ during datafile manipulation.
873: `column(x)` may be used only in expressions as part of `using` manipulations
874: to fits or datafile plots. See `plot datafile using`.
875: 4 tm_hour
876: ?expressions tm_hour
877: ?functions tm_hour
878: #tm\_hour(x) & int & the hour \\
879: %tm_hour(x)@int@the hour
880: The `tm_hour` function interprets its argument as a time, in seconds from
881: 1 Jan 2000. It returns the hour (an integer in the range 0--23) as a real.
882: 4 tm_mday
883: ?expressions tm_mday
884: ?functions tm_mday
885: #tm\_mday(x) & int & the day of the month \\
886: %tm_mday(x)@int@the day of the month
887: The `tm_mday` function interprets its argument as a time, in seconds from
888: 1 Jan 2000. It returns the day of the month (an integer in the range 1--31)
889: as a real.
890: 4 tm_min
891: ?expressions tm_min
892: ?functions tm_min
893: #tm\_min(x) & int & the minute \\
894: %tm_min(x)@int@the minute
895: The `tm_min` function interprets its argument as a time, in seconds from
896: 1 Jan 2000. It returns the minute (an integer in the range 0--59) as a real.
897: 4 tm_mon
898: ?expressions tm_mon
899: ?functions tm_mon
900: #tm\_mon(x) & int & the month \\
901: %tm_mon(x)@int@the month
902: The `tm_mon` function interprets its argument as a time, in seconds from
903: 1 Jan 2000. It returns the month (an integer in the range 1--12) as a real.
904: 4 tm_sec
905: ?expressions tm_sec
906: ?functions tm_sec
907: #tm\_sec(x) & int & the second \\
908: %tm_sec(x)@int@the second
909: The `tm_sec` function interprets its argument as a time, in seconds from
910: 1 Jan 2000. It returns the second (an integer in the range 0--59) as a real.
911: 4 tm_wday
912: ?expressions tm_wday
913: ?functions tm_wday
914: #tm\_wday(x) & int & the day of the week \\
915: %tm_wday(x)@int@the day of the week
916: The `tm_wday` function interprets its argument as a time, in seconds from
917: 1 Jan 2000. It returns the day of the week (an integer in the range 1--7) as
918: a real.
919: 4 tm_yday
920: ?expressions tm_yday
921: ?functions tm_yday
922: #tm\_yday(x) & int & the day of the year \\
923: %tm_yday(x)@int@the day of the year
924: The `tm_yday` function interprets its argument as a time, in seconds from
925: 1 Jan 2000. It returns the day of the year (an integer in the range 1--366)
926: as a real.
927: 4 tm_year
928: ?expressions tm_year
929: ?functions tm_year
930: #tm\_year(x) & int & the year \\
931: %tm_year(x)@int@the year
932: The `tm_year` function interprets its argument as a time, in seconds from
933: 1 Jan 2000. It returns the year (an integer) as a real.
934: 4 valid
935: ?expressions functions valid
936: ?functions valid
937: ?valid
938: #valid(x) & int & test validity of $\mbox{column}(x)$ during datafile manip.\\
939: %valid(x)@int@ test validity of column($x$) during datafile manip.
940: `valid(x)` may be used only in expressions as part of `using` manipulations
941: to fits or datafile plots. See `plot datafile using`.
942: @end table
943: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/airfoil/airfoil.html">Use of functions and complex variables for airfoils </a>
944: 3 Operators
945: ?expressions operators
946: ?operators
947: The operators in `gnuplot` are the same as the corresponding operators in the
948: C programming language, except that all operators accept integer, real, and
949: complex arguments, unless otherwise noted. The ** operator (exponentiation)
950: is supported, as in FORTRAN.
951:
952: Parentheses may be used to change order of evaluation.
953: 4 Unary
954: ?expressions operators unary
955: ?operators unary
956: ?unary
957: The following is a list of all the unary operators and their usages:
958:
959: @start table - first is interactive cleartext form
960: Symbol Example Explanation
961: - -a unary minus
962: + +a unary plus (no-operation)
963: ~ ~a * one's complement
964: ! !a * logical negation
965: ! a! * factorial
966: $ $3 * call arg/column during `using` manipulation
967: #\begin{tabular}{|ccl|} \hline
968: #\multicolumn{3}{|c|}{Unary Operators}\\ \hline \hline
969: #Symbol & Example & Explanation \\ \hline
970: #\verb@-@ & \verb@-a@ & unary minus \\
971: #\verb@+@ & \verb@+a@ & unary plus (no-operation) \\
972: #\verb@~@ & \verb@~a@ & * one's complement \\
973: #\verb@!@ & \verb@!a@ & * logical negation \\
974: #\verb@!@ & \verb@a!@ & * factorial \\
975: #\verb@$@ & \verb@$3@ & * call arg/column during `using` manipulation \\
976: C ugly hack: doc2ms uses $ as delimiter for eqn's so it doesn't seem to
977: C be able to print them. So we have to typeset this table without using
978: C eqn (at least that's the only solution I found, without any real docs
979: C on *roff and eqn
980: C First, terminate the table doc2ms.c already started:
981: %.TE
982: C ... then turn off eqn delimiters:
983: %.EQ
984: %delim off
985: %.EN
986: C ... and restart the table:
987: %.TS
988: %center box tab (@) ;
989: %c c l .
990: %Symbol@Example@Explanation
991: %_
992: %-@-a@unary minus
993: %+@+a@unary plus (no-operation)
994: %~@~a@* one's complement
995: %!@!a@* logical negation
996: %!@a!@* factorial
997: %$@$3@* call arg/column during `using` manipulation
998: %_
999: @end table
1000: (*) Starred explanations indicate that the operator requires an integer
1001: argument.
1002:
1003: Operator precedence is the same as in Fortran and C. As in those languages,
1004: parentheses may be used to change the order of operation. Thus -2**2 = -4,
1005: but (-2)**2 = 4.
1006:
1007: The factorial operator returns a real number to allow a greater range.
1008: 4 Binary
1009: ?expressions operators binary
1010: ?operators binary
1011: ?binary
1012: The following is a list of all the binary operators and their usages:
1013:
1014: @start table - first is interactive cleartext form
1015: Symbol Example Explanation
1016: ** a**b exponentiation
1017: * a*b multiplication
1018: / a/b division
1019: % a%b * modulo
1020: + a+b addition
1021: - a-b subtraction
1022: == a==b equality
1023: != a!=b inequality
1024: < a<b less than
1025: <= a<=b less than or equal to
1026: > a>b greater than
1027: >= a>=b greater than or equal to
1028: & a&b * bitwise AND
1029: ^ a^b * bitwise exclusive OR
1030: | a|b * bitwise inclusive OR
1031: && a&&b * logical AND
1032: || a||b * logical OR
1033: #\begin{tabular}{|ccl|} \hline
1034: #\multicolumn{3}{|c|}{Binary Operators} \\ \hline \hline
1035: #Symbol & Example & Explanation \\ \hline
1036: #\verb~**~ & \verb~a**b~ & exponentiation\\
1037: #\verb~*~ & \verb~a*b~ & multiplication\\
1038: #\verb~/~ & \verb~a/b~ & division\\
1039: #\verb~%~ & \verb~a%b~ & * modulo\\
1040: #\verb~+~ & \verb~a+b~ & addition\\
1041: #\verb~-~ & \verb~a-b~ & subtraction\\
1042: #\verb~==~ & \verb~a==b~ & equality\\
1043: #\verb~!=~ & \verb~a!=b~ & inequality\\
1044: #\verb~<~ & \verb~a<b~ & less than\\
1045: #\verb~<=~ & \verb~a<=b~ & less than or equal to\\
1046: #\verb~>~ & \verb~a>b~ & greater than\\
1047: #\verb~>=~ & \verb~a>=b~ & greater than or equal to\\
1048: #\verb~&~ & \verb~a&b~ & * bitwise AND\\
1049: #\verb~^~ & \verb~a^b~ & * bitwise exclusive OR\\
1050: #\verb~|~ & \verb~a|b~ & * bitwise inclusive OR\\
1051: #\verb~&&~ & \verb~a&&b~ & * logical AND\\
1052: #\verb~||~ & \verb~a||b~ & * logical OR\\
1053: %c c l .
1054: %Symbol@Example@Explanation
1055: %_
1056: %**@a**b@exponentiation
1057: %*@a*b@multiplication
1058: %/@a/b@division
1059: %%@a%b@* modulo
1060: %+@a+b@addition
1061: %-@a-b@subtraction
1062: %==@a==b@equality
1063: %!=@a!=b@inequality
1064: %<@a<b@less than
1065: %<=@a<=b@less than or equal to
1066: %>@a>b@greater than
1067: %>=@a>=b@greater than or equal to
1068: %&@a&b@* bitwise AND
1069: %^@a^b@* bitwise exclusive OR
1070: %|@a|b@* bitwise inclusive OR
1071: %&&@a&&b@* logical AND
1072: %||@a||b@* logical OR
1073:
1074: @end table
1075: (*) Starred explanations indicate that the operator requires integer
1076: arguments.
1077:
1078: Logical AND (&&) and OR (||) short-circuit the way they do in C. That is,
1079: the second `&&` operand is not evaluated if the first is false; the second
1080: `||` operand is not evaluated if the first is true.
1081: 4 Ternary
1082: ?expressions operators ternary
1083: ?operators ternary
1084: ?ternary
1085: There is a single ternary operator:
1086:
1087: @start table - first is interactive cleartext form
1088: Symbol Example Explanation
1089: ?: a?b:c ternary operation
1090: #\begin{tabular}{|ccl|} \hline
1091: #\multicolumn{3}{|c|}{Ternary Operator} \\ \hline \hline
1092: #Symbol & Example & Explanation \\ \hline
1093: #\verb~?:~ & \verb~a?b:c~ & ternary operation\\
1094: %c c l .
1095: %Symbol@Example@Explanation
1096: %_
1097: %?:@a?b:c@* ternary operation
1098:
1099: @end table
1100: The ternary operator behaves as it does in C. The first argument (a), which
1101: must be an integer, is evaluated. If it is true (non-zero), the second
1102: argument (b) is evaluated and returned; otherwise the third argument (c) is
1103: evaluated and returned.
1104:
1105: The ternary operator is very useful both in constructing piecewise functions
1106: and in plotting points only when certain conditions are met.
1107:
1108: Examples:
1109:
1110: Plot a function that is to equal sin(x) for 0 <= x < 1, 1/x for 1 <= x < 2,
1111: and undefined elsewhere:
1112: f(x) = 0<=x && x<1 ? sin(x) : 1<=x && x<2 ? 1/x : 1/0
1113: plot f(x)
1114: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/ternary.gif" alt="[ternary.gif]" width=640 height=480>
1115: Note that `gnuplot` quietly ignores undefined values, so the final branch of
1116: the function (1/0) will produce no plottable points. Note also that f(x)
1117: will be plotted as a continuous function across the discontinuity if a line
1118: style is used. To plot it discontinuously, create separate functions for the
1119: two pieces. (Parametric functions are also useful for this purpose.)
1120:
1121: For data in a file, plot the average of the data in columns 2 and 3 against
1122: the datum in column 1, but only if the datum in column 4 is non-negative:
1123:
1124: plot 'file' using 1:( $4<0 ? 1/0 : ($2+$3)/2 )
1125:
1126: Please see `plot data-file using` for an explanation of the `using` syntax.
1127: 3 User-defined
1128: ?expressions user-defined
1129: ?user-defined
1130: ?variables
1131: New user-defined variables and functions of one through five variables may
1132: be declared and used anywhere, including on the `plot` command itself.
1133:
1134: User-defined function syntax:
1135: <func-name>( <dummy1> {,<dummy2>} ... {,<dummy5>} ) = <expression>
1136:
1137: where <expression> is defined in terms of <dummy1> through <dummy5>.
1138:
1139: User-defined variable syntax:
1140: <variable-name> = <constant-expression>
1141:
1142: Examples:
1143: w = 2
1144: q = floor(tan(pi/2 - 0.1))
1145: f(x) = sin(w*x)
1146: sinc(x) = sin(pi*x)/(pi*x)
1147: delta(t) = (t == 0)
1148: ramp(t) = (t > 0) ? t : 0
1149: min(a,b) = (a < b) ? a : b
1150: comb(n,k) = n!/(k!*(n-k)!)
1151: len3d(x,y,z) = sqrt(x*x+y*y+z*z)
1152: plot f(x) = sin(x*a), a = 0.2, f(x), a = 0.4, f(x)
1153:
1154: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/userdefined.gif" alt="[userdefined.gif]" width=640 height=480>
1155: Note that the variable `pi` is already defined. But it is in no way magic;
1156: you may redefine it to be whatever you like.
1157:
1158: Valid names are the same as in most programming languages: they must begin
1159: with a letter, but subsequent characters may be letters, digits, "$", or "_".
1160: Note, however, that the `fit` mechanism uses several variables with names
1161: that begin "FIT_". It is safest to avoid using such names. "FIT_LIMIT",
1162: however, is one that you may wish to redefine. See the documentation
1163: on `fit` for details.
1164:
1165:
1166: See `show functions`, `show variables`, and `fit`.
1167: 2 Glossary
1168: ?glossary
1169: Throughout this document an attempt has been made to maintain consistency of
1170: nomenclature. This cannot be wholly successful because as `gnuplot` has
1171: evolved over time, certain command and keyword names have been adopted that
1172: preclude such perfection. This section contains explanations of the way
1173: some of these terms are used.
1174:
1175: A "page" or "screen" is the entire area addressable by `gnuplot`. On a
1176: monitor, it is the full screen; on a plotter, it is a single sheet of paper.
1177:
1178: A screen may contain one or more "plots". A plot is defined by an abscissa
1179: and an ordinate, although these need not actually appear on it, as well as
1180: the margins and any text written therein.
1181:
1182: A plot contains one "graph". A graph is defined by an abscissa and an
1183: ordinate, although these need not actually appear on it.
1184:
1185: A graph may contain one or more "lines". A line is a single function or
1186: data set. "Line" is also a plotting style. The word will also be used in
1187: sense "a line of text". Presumably the context will remove any ambiguity.
1188:
1189: The lines on a graph may have individual names. These may be listed
1190: together with a sample of the plotting style used to represent them in
1191: the "key", sometimes also called the "legend".
1192:
1193: The word "title" occurs with multiple meanings in `gnuplot`. In this
1194: document, it will always be preceded by the adjective "plot", "line", or
1195: "key" to differentiate among them.
1196:
1197: A graph may have up to four labelled axes. Various commands have the name of
1198: an axis built into their names, such as `set xlabel`. Other commands have
1199: one or more axis names as options, such as `set logscale xy`. The names of
1200: the four axes for these usages are "x" for the axis along the bottom border
1201: of the plot, "y" for the left border, "x2" for the top border, and "y2" for
1202: the right border. "z" also occurs in commands used with 3-d plotting.
1203:
1204: When discussing data files, the term "record" will be resurrected and used
1205: to denote a single line of text in the file, that is, the characters between
1206: newline or end-of-record characters. A "point" is the datum extracted from
1207: a single record. A "datablock" is a set of points from consecutive records,
1208: delimited by blank records. A line, when referred to in the context of a
1209: data file, is a subset of a datablock.
1210: 2 Plotting
1211: ?plotting
1212: There are three `gnuplot` commands which actually create a plot: `plot`,
1213: `splot` and `replot`. `plot` generates 2-d plots, `splot` generates 3-d
1214: plots (actually 2-d projections, of course), and `replot` appends its
1215: arguments to the previous `plot` or `splot` and executes the modified
1216: command.
1217:
1218: Much of the general information about plotting can be found in the discussion
1219: of `plot`; information specific to 3-d can be found in the `splot` section.
1220:
1221: `plot` operates in either rectangular or polar coordinates -- see `set polar`
1222: for details of the latter. `splot` operates only in rectangular coordinates,
1223: but the `set mapping` command allows for a few other coordinate systems to be
1224: treated. In addition, the `using` option allows both `plot` and `splot` to
1225: treat almost any coordinate system you'd care to define.
1226:
1227: `splot` can plot surfaces and contours in addition to points and/or lines.
1228: In addition to `splot`, see `set isosamples` for information about defining
1229: the grid for a 3-d function; `splot datafile` for information about the
1230: requisite file structure for 3-d data values; and `set contour` and `set
1231: cntrparam` for information about contours.
1232: 2 Start-up
1233: ?startup
1234: ?start
1235: ?.gnuplot
1236: When `gnuplot` is run, it looks for an initialization file to load. This
1237: file is called `.gnuplot` on Unix and AmigaOS systems, and `GNUPLOT.INI` on
1238: other systems. If this file is not found in the current directory, the
1239: program will look for it in the home directory (under AmigaOS,
1240: Atari(single)TOS, MS-DOS and OS/2, the environment variable `gnuplot` should
1241: contain the name of this directory). Note: if NOCWDRC is defined during the
1242: installation, `gnuplot` will not read from the current directory.
1243:
1244: If the initialization file is found, `gnuplot` executes the commands in it.
1245: These may be any legal `gnuplot` commands, but typically they are limited to
1246: setting the terminal and defining frequently-used functions or variables.
1247: 2 Substitution
1248: ?substitution
1249: Command-line substitution is specified by a system command enclosed in
1250: backquotes. This command is spawned and the output it produces replaces
1251: the name of the command (and backquotes) on the command line. Some
1252: implementations also support pipes; see `plot data-file special-filenames`.
1253:
1254: Newlines in the output produced by the spawned command are replaced with
1255: blanks.
1256:
1257: Command-line substitution can be used anywhere on the `gnuplot` command
1258: line.
1259:
1260: Example:
1261:
1262: This will run the program `leastsq` and replace `leastsq` (including
1263: backquotes) on the command line with its output:
1264: f(x) = `leastsq`
1265:
1266: or, in VMS
1267: f(x) = `run leastsq`
1268: 2 Syntax
1269: ?syntax
1270: ?specify
1271: ?punctuation
1272: The general rules of syntax and punctuation in `gnuplot` are that keywords
1273: and options are order-dependent. Options and any accompanying parameters are
1274: separated by spaces whereas lists and coordinates are separated by commas.
1275: Ranges are separated by colons and enclosed in brackets [], text and file
1276: names are enclosed in quotes, and a few miscellaneous things are enclosed
1277: in parentheses. Braces {} are used for a few special purposes.
1278:
1279: Commas are used to separate coordinates on the `set` commands `arrow`,
1280: `key`, and `label`; the list of variables being fitted (the list after the
1281: `via` keyword on the `fit` command); lists of discrete contours or the loop
1282: parameters which specify them on the `set cntrparam` command; the arguments
1283: of the `set` commands `dgrid3d`, `dummy`, `isosamples`, `offsets`, `origin`,
1284: `samples`, `size`, `time`, and `view`; lists of tics or the loop parameters
1285: which specify them; the offsets for titles and axis labels; parametric
1286: functions to be used to calculate the x, y, and z coordinates on the `plot`,
1287: `replot` and `splot` commands; and the complete sets of keywords specifying
1288: individual plots (data sets or functions) on the `plot`, `replot` and `splot`
1289: commands.
1290:
1291: Parentheses are used to delimit sets of explicit tics (as opposed to loop
1292: parameters) and to indicate computations in the `using` filter of the `fit`,
1293: `plot`, `replot` and `splot` commands.
1294:
1295: (Parentheses and commas are also used as usual in function notation.)
1296:
1297: Brackets are used to delimit ranges, whether they are given on `set`, `plot`
1298: or `splot` commands.
1299:
1300: Colons are used to separate extrema in `range` specifications (whether they
1301: are given on `set`, `plot` or `splot` commands) and to separate entries in
1302: the `using` filter of the `plot`, `replot`, `splot` and `fit` commands.
1303:
1304: Semicolons are used to separate commands given on a single command line.
1305:
1306: Braces are used in text to be specially processed by some terminals, like
1307: `postscript`. They are also used to denote complex numbers: {3,2} = 3 + 2i.
1308:
1309: Text may be enclosed in single- or double-quotes. Backslash processing of
1310: sequences like \n (newline) and \345 (octal character code) is performed for
1311: double-quoted strings, but not for single-quoted strings.
1312:
1313: The justification is the same for each line of a multi-line string. Thus the
1314: center-justified string
1315: "This is the first line of text.\nThis is the second line."
1316: will produce
1317: This is the first line of text.
1318: This is the second line.
1319: but
1320: 'This is the first line of text.\nThis is the second line.'
1321: will produce
1322: This is the first line of text.\nThis is the second line.
1323:
1324: Filenames may be entered with either single- or double-quotes. In this
1325: manual the command examples generally single-quote filenames and double-quote
1326: other string tokens for clarity.
1327:
1328: At present you should not embed \n inside {} when using the enhanced option
1329: of the postscript terminal.
1330:
1331: The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow a newline to be
1332: specified by \\ in a single-quoted string or \\\\ in a double-quoted string.
1333:
1334: Back-quotes are used to enclose system commands for substitution.
1335: 2 Time/Date data
1336: ?time/date
1337: `gnuplot` supports the use of time and/or date information as input data.
1338: This feature is activated by the commands `set xdata time`, `set ydata time`,
1339: etc.
1340:
1341: Internally all times and dates are converted to the number of seconds from
1342: the year 2000. The command `set timefmt` defines the format for all inputs:
1343: data files, ranges, tics, label positions---in short, anything that accepts a
1344: data value must receive it in this format. Since only one input format can
1345: be in force at a given time, all time/date quantities being input at the same
1346: time must be presented in the same format. Thus if both x and y data in a
1347: file are time/date, they must be in the same format.
1348:
1349: The conversion to and from seconds assumes Universal Time (which is the same
1350: as Greenwich Standard Time). There is no provision for changing the time
1351: zone or for daylight savings. If all your data refer to the same time zone
1352: (and are all either daylight or standard) you don't need to worry about these
1353: things. But if the absolute time is crucial for your application, you'll
1354: need to convert to UT yourself.
1355:
1356: Commands like `show xrange` will re-interpret the integer according to
1357: `timefmt`. If you change `timefmt`, and then `show` the quantity again, it
1358: will be displayed in the new `timefmt`. For that matter, if you give the
1359: deactivation command (like `set xdata`), the quantity will be shown in its
1360: numerical form.
1361:
1362: The command `set format` defines the format that will be used for tic labels,
1363: whether or not the specified axis is time/date.
1364:
1365: If time/date information is to be plotted from a file, the `using` option
1366: _must_ be used on the `plot` or `splot` command. These commands simply use
1367: white space to separate columns, but white space may be embedded within the
1368: time/date string. If you use tabs as a separator, some trial-and-error may
1369: be necessary to discover how your system treats them.
1370:
1371: The following example demonstrates time/date plotting.
1372:
1373: Suppose the file "data" contains records like
1374:
1375: 03/21/95 10:00 6.02e23
1376:
1377: This file can be plotted by
1378:
1379: set xdata time
1380: set timefmt "%m/%d/%y"
1381: set xrange ["03/21/95":"03/22/95"]
1382: set format x "%m/%d"
1383: set timefmt "%m/%d/%y %H:%M"
1384: plot "data" using 1:3
1385:
1386: which will produce xtic labels that look like "03/21".
1387:
1388: See the descriptions of each command for more details.
1389: 1 Commands
1390: ?commands
1391: This section lists the commands acceptable to `gnuplot` in alphabetical
1392: order. Printed versions of this document contain all commands; on-line
1393: versions may not be complete. Indeed, on some systems there may be no
1394: commands at all listed under this heading.
1395:
1396: Note that in most cases unambiguous abbreviations for command names and their
1397: options are permissible, i.e., "`p f(x) w l`" instead of "`plot f(x) with
1398: lines`".
1399:
1400: In the syntax descriptions, braces ({}) denote optional arguments and a
1401: vertical bar (|) separates mutually exclusive choices.
1402: 2 cd
1403: ?commands cd
1404: ?cd
1405: The `cd` command changes the working directory.
1406:
1407: Syntax:
1408: cd '<directory-name>'
1409:
1410: The directory name must be enclosed in quotes.
1411:
1412: Examples:
1413: cd 'subdir'
1414: cd ".."
1415:
1416: DOS users _must_ use single-quotes---backslash [\] has special significance
1417: inside double-quotes. For example,
1418: cd "c:\newdata"
1419: fails, but
1420: cd 'c:\newdata'
1421: works as expected.
1422: 2 call
1423: ?commands call
1424: ?call
1425: The `call` command is identical to the load command with one exception: you
1426: can have up to ten additional parameters to the command (delimited according
1427: to the standard parser rules) which can be substituted into the lines read
1428: from the file. As each line is read from the `call`ed input file, it is
1429: scanned for the sequence `$` (dollar-sign) followed by a digit (0--9). If
1430: found, the sequence is replaced by the corresponding parameter from the
1431: `call` command line. If the parameter was specified as a string in the
1432: `call` line, it is substituted without its enclosing quotes. `$` followed by
1433: any character other than a digit will be that character. E.g. use `$$` to
1434: get a single `$`. Providing more than ten parameters on the `call` command
1435: line will cause an error. A parameter that was not provided substitutes as
1436: nothing. Files being `call`ed may themselves contain `call` or `load`
1437: commands.
1438:
1439: The `call` command _must_ be the last command on a multi-command line.
1440:
1441: Syntax:
1442: call "<input-file>" <parameter-0> <parm-1> ... <parm-9>
1443:
1444: The name of the input file must be enclosed in quotes, and it is recommended
1445: that parameters are similarly enclosed in quotes (future versions of gnuplot
1446: may treat quoted and unquoted arguments differently).
1447:
1448: Example:
1449:
1450: If the file 'calltest.gp' contains the line:
1451: print "p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"
1452:
1453: entering the command:
1454: call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"
1455:
1456: will display:
1457: p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx
1458:
1459: NOTE: there is a clash in syntax with the datafile `using` callback
1460: operator. Use `$$n` or `column(n)` to access column n from a datafile inside
1461: a `call`ed datafile plot.
1462: 2 clear
1463: ?commands clear
1464: ?clear
1465: The `clear` command erases the current screen or output device as specified
1466: by `set output`. This usually generates a formfeed on hardcopy devices. Use
1467: `set terminal` to set the device type.
1468:
1469: For some terminals `clear` erases only the portion of the plotting surface
1470: defined by `set size`, so for these it can be used in conjunction with `set
1471: multiplot` to create an inset.
1472:
1473: Example:
1474: set multiplot
1475: plot sin(x)
1476: set origin 0.5,0.5
1477: set size 0.4,0.4
1478: clear
1479: plot cos(x)
1480: set nomultiplot
1481:
1482: Please see `set multiplot`, `set size`, and `set origin` for details of these
1483: commands.
1484: 2 exit
1485: ?commands exit
1486: ?exit
1487: The commands `exit` and `quit` and the END-OF-FILE character will exit the
1488: current `gnuplot` command file and `load` the next one. See "help
1489: batch/interactive" for more details.
1490:
1491: Each of these commands will clear the output device (as does the `clear`
1492: command) before exiting.
1493: 2 fit
1494: ?commands fit
1495: ?fit
1496: ?least-squares
1497: ?Marquardt
1498: The `fit` command can fit a user-defined function to a set of data points
1499: (x,y) or (x,y,z), using an implementation of the nonlinear least-squares
1500: (NLLS) Marquardt-Levenberg algorithm. Any user-defined variable occurring in
1501: the function body may serve as a fit parameter, but the return type of the
1502: function must be real.
1503:
1504: Syntax:
1505: fit {[xrange] {[yrange]}} <function> '<datafile>'
1506: {datafile-modifiers}
1507: via '<parameter file>' | <var1>{,<var2>,...}
1508:
1509: Ranges may be specified to temporarily limit the data which is to be fitted;
1510: any out-of-range data points are ignored. The syntax is
1511: [{dummy_variable=}{<min>}{:<max>}],
1512: analogous to `plot`; see `plot ranges`.
1513:
1514: <function> is any valid `gnuplot` expression, although it is usual to use a
1515: previously user-defined function of the form f(x) or f(x,y).
1516:
1517: <datafile> is treated as in the `plot` command. All the `plot datafile`
1518: modifiers (`using`, `every`,...) except `smooth` are applicable to `fit`.
1519: See `plot datafile`.
1520:
1521: The default data formats for fitting functions with a single independent
1522: variable, y=f(x), are {x:}y or x:y:s; those formats can be changed with
1523: the datafile `using` qualifier. The third item, (a column number or an
1524: expression), if present, is interpreted as the standard deviation of the
1525: corresponding y value and is used to compute a weight for the datum, 1/s**2.
1526: Otherwise, all data points are weighted equally, with a weight of one.
1527:
1528: To fit a function with two independent variables, z=f(x,y), the required
1529: format is `using` with four items, x:y:z:s. The complete format must be
1530: given---no default columns are assumed for a missing token. Weights for
1531: each data point are evaluated from 's' as above. If error estimates are
1532: not available, a constant value can be specified as a constant expression
1533: (see `plot datafile using`), e.g., `using 1:2:3:(1)`.
1534:
1535: Multiple datasets may be simultaneously fit with functions of one
1536: independent variable by making y a 'pseudo-variable', e.g., the dataline
1537: number, and fitting as two independent variables. See `fit multibranch`.
1538:
1539: The `via` qualifier specifies which parameters are to be adjusted, either
1540: directly, or by referencing a parameter file.
1541:
1542: Examples:
1543: f(x) = a*x**2 + b*x + c
1544: g(x,y) = a*x**2 + b*y**2 + c*x*y
1545: FIT_LIMIT = 1e-6
1546: fit f(x) 'measured.dat' via 'start.par'
1547: fit f(x) 'measured.dat' using 3:($7-5) via 'start.par'
1548: fit f(x) './data/trash.dat' using 1:2:3 via a, b, c
1549: fit g(x,y) 'surface.dat' using 1:2:3:(1) via a, b, c
1550:
1551: After each iteration step, detailed information about the current state
1552: of the fit is written to the display. The same information about the
1553: initial and final states is written to a log file, "fit.log". This file
1554: is always appended to, so as to not lose any previous fit history; it
1555: should be deleted or renamed as desired.
1556:
1557: The fit may be interrupted by pressing Ctrl-C (any key but Ctrl-C under
1558: MSDOS and Atari Multitasking Systems). After the current iteration
1559: completes, you have the option to (1) stop the fit and accept the current
1560: parameter values, (2) continue the fit, (3) execute a `gnuplot` command
1561: as specified by the environment variable FIT_SCRIPT. The default for
1562: FIT_SCRIPT is `replot`, so if you had previously plotted both the data
1563: and the fitting function in one graph, you can display the current state
1564: of the fit.
1565:
1566: Once `fit` has finished, the `update` command may be used to store final
1567: values in a file for subsequent use as a parameter file. See `update`
1568: for details.
1569: 3 adjustable parameters
1570: ?commands fit parameters
1571: ?fit parameters
1572: ?commands fit adjustable_parameters
1573: ?fit adjustable_parameters
1574: ?fit_parameters
1575: There are two ways that `via` can specify the parameters to be adjusted,
1576: either directly on the command line or indirectly, by referencing a
1577: parameter file. The two use different means to set initial values.
1578:
1579: Adjustable parameters can be specified by a comma-separated list of variable
1580: names after the `via` keyword. Any variable that is not already defined is
1581: is created with an initial value of 1.0. However, the fit is more likely
1582: to converge rapidly if the variables have been previously declared with more
1583: appropriate starting values.
1584:
1585: In a parameter file, each parameter to be varied and a corresponding initial
1586: value are specified, one per line, in the form
1587: varname = value
1588:
1589: Comments, marked by '#', and blank lines are permissible. The
1590: special form
1591: varname = value # FIXED
1592:
1593: means that the variable is treated as a 'fixed parameter', initialized by the
1594: parameter file, but not adjusted by `fit`. For clarity, it may be useful to
1595: designate variables as fixed parameters so that their values are reported by
1596: `fit`. The keyword `# FIXED` has to appear in exactly this form.
1597:
1598: 3 beginner's guide
1599: ?commands fit beginners_guide
1600: ?fit beginners_guide
1601: ?fit guide
1602: ?fitting
1603: `fit` is used to find a set of parameters that 'best' fits your data to your
1604: user-defined function. The fit is judged on the basis of the the sum of the
1605: squared differences or 'residuals' (SSR) between the input data points and
1606: the function values, evaluated at the same places. This quantity is often
1607: called 'chisquare' (i.e., the Greek letter chi, to the power of 2). The
1608: algorithm attempts to minimize SSR, or more precisely, WSSR, as the residuals
1609: are 'weighted' by the input data errors (or 1.0) before being squared; see
1610: `fit error_estimates` for details.
1611:
1612: That's why it is called 'least-squares fitting'. Let's look at an example
1613: to see what is meant by 'non-linear', but first we had better go over some
1614: terms. Here it is convenient to use z as the dependent variable for
1615: user-defined functions of either one independent variable, z=f(x), or two
1616: independent variables, z=f(x,y). A parameter is a user-defined variable
1617: that `fit` will adjust, i.e., an unknown quantity in the function
1618: declaration. Linearity/non-linearity refers to the relationship of the
1619: dependent variable, z, to the parameters which `fit` is adjusting, not of
1620: z to the independent variables, x and/or y. (To be technical, the
1621: second {and higher} derivatives of the fitting function with respect to
1622: the parameters are zero for a linear least-squares problem).
1623:
1624: For linear least-squares (LLS), the user-defined function will be a sum of
1625: simple functions, not involving any parameters, each multiplied by one
1626: parameter. NLLS handles more complicated functions in which parameters can
1627: be used in a large number of ways. An example that illustrates the
1628: difference between linear and nonlinear least-squares is the Fourier series.
1629: One member may be written as
1630: z=a*sin(c*x) + b*cos(c*x).
1631: If a and b are the unknown parameters and c is constant, then estimating
1632: values of the parameters is a linear least-squares problem. However, if
1633: c is an unknown parameter, the problem is nonlinear.
1634:
1635: In the linear case, parameter values can be determined by comparatively
1636: simple linear algebra, in one direct step. However LLS is a special case
1637: which is also solved along with more general NLLS problems by the iterative
1638: procedure that `gnuplot` uses. `fit` attempts to find the minimum by doing
1639: a search. Each step (iteration) calculates WSSR with a new set of parameter
1640: values. The Marquardt-Levenberg algorithm selects the parameter values for
1641: the next iteration. The process continues until a preset criterium is met,
1642: either (1) the fit has "converged" (the relative change in WSSR is less than
1643: FIT_LIMIT), or (2) it reaches a preset iteration count limit, FIT_MAXITER
1644: (see `fit control variables`). The fit may also be interrupted
1645: and subsequently halted from the keyboard (see `fit`).
1646:
1647: Often the function to be fitted will be based on a model (or theory) that
1648: attempts to describe or predict the behaviour of the data. Then `fit` can
1649: be used to find values for the free parameters of the model, to determine
1650: how well the data fits the model, and to estimate an error range for each
1651: parameter. See `fit error_estimates`.
1652:
1653: Alternatively, in curve-fitting, functions are selected independent of
1654: a model (on the basis of experience as to which are likely to describe
1655: the trend of the data with the desired resolution and a minimum number
1656: of parameters*functions.) The `fit` solution then provides an analytic
1657: representation of the curve.
1658:
1659: However, if all you really want is a smooth curve through your data points,
1660: the `smooth` option to `plot` may be what you've been looking for rather
1661: than `fit`.
1662: 3 error estimates
1663: ?commands fit error_estimate
1664: ?fit error_estimate
1665: ?fit errors
1666: In `fit`, the term "error" is used in two different contexts, data error
1667: estimates and parameter error estimates.
1668:
1669: Data error estimates are used to calculate the relative weight of each data
1670: point when determining the weighted sum of squared residuals, WSSR or
1671: chisquare. They can affect the parameter estimates, since they determine
1672: how much influence the deviation of each data point from the fitted function
1673: has on the final values. Some of the `fit` output information, including
1674: the parameter error estimates, is more meaningful if accurate data error
1675: estimates have been provided.
1676:
1677: The 'statistical overview' describes some of the `fit` output and gives some
1678: background for the 'practical guidelines'.
1679: 4 statistical overview
1680: ?commands fit error statistical_overview
1681: ?fit error statistical_overview
1682: ?statistical_overview
1683: The theory of non-linear least-squares (NLLS) is generally described in terms
1684: of a normal distribution of errors, that is, the input data is assumed to be
1685: a sample from a population having a given mean and a Gaussian (normal)
1686: distribution about the mean with a given standard deviation. For a sample of
1687: sufficiently large size, and knowing the population standard deviation, one
1688: can use the statistics of the chisquare distribution to describe a "goodness
1689: of fit" by looking at the variable often called "chisquare". Here, it is
1690: sufficient to say that a reduced chisquare (chisquare/degrees of freedom,
1691: where degrees of freedom is the number of datapoints less the number of
1692: parameters being fitted) of 1.0 is an indication that the weighted sum of
1693: squared deviations between the fitted function and the data points is the
1694: same as that expected for a random sample from a population characterized by
1695: the function with the current value of the parameters and the given standard
1696: deviations.
1697:
1698: If the standard deviation for the population is not constant, as in counting
1699: statistics where variance = counts, then each point should be individually
1700: weighted when comparing the observed sum of deviations and the expected sum
1701: of deviations.
1702:
1703: At the conclusion `fit` reports 'stdfit', the standard deviation of the fit,
1704: which is the rms of the residuals, and the variance of the residuals, also
1705: called 'reduced chisquare' when the data points are weighted. The number of
1706: degrees of freedom (the number of data points minus the number of fitted
1707: parameters) is used in these estimates because the parameters used in
1708: calculating the residuals of the datapoints were obtained from the same data.
1709:
1710: To estimate confidence levels for the parameters, one can use the minimum
1711: chisquare obtained from the fit and chisquare statistics to determine the
1712: value of chisquare corresponding to the desired confidence level, but
1713: considerably more calculation is required to determine the combinations of
1714: parameters which produce such values.
1715:
1716: Rather than determine confidence intervals, `fit` reports parameter error
1717: estimates which are readily obtained from the variance-covariance matrix
1718: after the final iteration. By convention, these estimates are called
1719: "standard errors" or "asymptotic standard errors", since they are calculated
1720: in the same way as the standard errors (standard deviation of each parameter)
1721: of a linear least-squares problem, even though the statistical conditions for
1722: designating the quantity calculated to be a standard deviation are not
1723: generally valid for the NLLS problem. The asymptotic standard errors are
1724: generally over-optimistic and should not be used for determining confidence
1725: levels, but are useful for qualitative purposes.
1726:
1727: The final solution also produces a correlation matrix, which gives an
1728: indication of the correlation of parameters in the region of the solution;
1729: if one parameter is changed, increasing chisquare, does changing another
1730: compensate? The main diagonal elements, autocorrelation, are all 1; if
1731: all parameters were independent, all other elements would be nearly 0. Two
1732: variables which completely compensate each other would have an off-diagonal
1733: element of unit magnitude, with a sign depending on whether the relation is
1734: proportional or inversely proportional. The smaller the magnitudes of the
1735: off-diagonal elements, the closer the estimates of the standard deviation
1736: of each parameter would be to the asymptotic standard error.
1737: 4 practical guidelines
1738: ?commands fit error practical_guidelines
1739: ?fit error practical_guidelines
1740: ?practical_guidelines
1741: ?guidelines
1742: If you have a basis for assigning weights to each data point, doing so lets
1743: you make use of additional knowledge about your measurements, e.g., take into
1744: account that some points may be more reliable than others. That may affect
1745: the final values of the parameters.
1746:
1747: Weighting the data provides a basis for interpreting the additional `fit`
1748: output after the last iteration. Even if you weight each point equally,
1749: estimating an average standard deviation rather than using a weight of 1
1750: makes WSSR a dimensionless variable, as chisquare is by definition.
1751:
1752: Each fit iteration will display information which can be used to evaluate
1753: the progress of the fit. (An '*' indicates that it did not find a smaller
1754: WSSR and is trying again.) The 'sum of squares of residuals', also called
1755: 'chisquare', is the WSSR between the data and your fitted function; `fit`
1756: has minimized that. At this stage, with weighted data, chisquare is expected
1757: to approach the number of degrees of freedom (data points minus parameters).
1758: The WSSR can be used to calculate the reduced chisquare (WSSR/ndf) or stdfit,
1759: the standard deviation of the fit, sqrt(WSSR/ndf). Both of these are
1760: reported for the final WSSR.
1761:
1762: If the data are unweighted, stdfit is the rms value of the deviation of the
1763: data from the fitted function, in user units.
1764:
1765: If you supplied valid data errors, the number of data points is large enough,
1766: and the model is correct, the reduced chisquare should be about unity. (For
1767: details, look up the 'chi-squared distribution' in your favourite statistics
1768: reference.) If so, there are additional tests, beyond the scope of this
1769: overview, for determining how well the model fits the data.
1770:
1771: A reduced chisquare much larger than 1.0 may be due to incorrect data error
1772: estimates, data errors not normally distributed, systematic measurement
1773: errors, 'outliers', or an incorrect model function. A plot of the residuals,
1774: e.g., `plot 'datafile' using 1:($2-f($1))`, may help to show any systematic
1775: trends. Plotting both the data points and the function may help to suggest
1776: another model.
1777:
1778: Similarly, a reduced chisquare less than 1.0 indicates WSSR is less than that
1779: expected for a random sample from the function with normally distributed
1780: errors. The data error estimates may be too large, the statistical
1781: assumptions may not be justified, or the model function may be too general,
1782: fitting fluctuations in a particular sample in addition to the underlying
1783: trends. In the latter case, a simpler function may be more appropriate.
1784:
1785: You'll have to get used to both `fit` and the kind of problems you apply it
1786: to before you can relate the standard errors to some more practical estimates
1787: of parameter uncertainties or evaluate the significance of the correlation
1788: matrix.
1789:
1790: Note that `fit`, in common with most NLLS implementations, minimizes the
1791: weighted sum of squared distances (y-f(x))**2. It does not provide any means
1792: to account for "errors" in the values of x, only in y. Also, any "outliers"
1793: (data points outside the normal distribution of the model) will have an
1794: exaggerated effect on the solution.
1795: 3 fit controlling
1796: ?commands fit_control
1797: ?fit_control
1798: ?fit control
1799: There are a number of `gnuplot` variables that can be defined to affect
1800: `fit`. Those which can be defined once `gnuplot` is running are listed
1801: under 'control_variables' while those defined before starting `gnuplot`
1802: are listed under 'environment_variables'.
1803: 4 control variables
1804: ?commands fit_control variables
1805: ?fit_control variables
1806: ?fit control variables
1807: The default epsilon limit (1e-5) may be changed by declaring a value for
1808: FIT_LIMIT
1809: When the sum of squared residuals changes between two iteration steps by
1810: a factor less than this number (epsilon), the fit is considered to have
1811: 'converged'.
1812:
1813: The maximum number of iterations may be limited by declaring a value for
1814: FIT_MAXITER
1815: A value of 0 (or not defining it at all) means that there is no limit.
1816:
1817: If you need even more control about the algorithm, and know the
1818: Marquardt-Levenberg algorithm well, there are some more variables to
1819: influence it. The startup value of `lambda` is normally calculated
1820: automatically from the ML-matrix, but if you want to, you may provide
1821: your own one with
1822: FIT_START_LAMBDA
1823: Specifying FIT_START_LAMBDA as zero or less will re-enable the automatic
1824: selection. The variable
1825: FIT_LAMBDA_FACTOR
1826: gives the factor by which `lambda` is increased or decreased whenever
1827: the chi-squared target function increased or decreased significantly.
1828: Setting FIT_LAMBDA_FACTOR to zero re-enables the default factor of
1829: 10.0.
1830:
1831: Oher variables with the FIT_ prefix may be added to `fit`, so it is safer
1832: not to use that prefix for user-defined variables.
1833:
1834: The variables FIT_SKIP and FIT_INDEX were used by earlier releases of
1835: `gnuplot` with a 'fit' patch called `gnufit` and are no longer available.
1836: The datafile `every` modifier provides the functionality of FIT_SKIP.
1837: FIT_INDEX was used for multi-branch fitting, but multi-branch fitting of
1838: one independent variable is now done as a pseudo-3D fit in which the
1839: second independent variable and `using` are used to specify the branch.
1840: See `fit multi-branch`.
1841: 4 environment variables
1842: ?commands fit_control environment
1843: ?fit_control environment
1844: ?fit control environment
1845: The environment variables must be defined before `gnuplot` is executed; how
1846: to do so depends on your operating system.
1847:
1848: FIT_LOG
1849: changes the name (and/or path) of the file to which the fit log will be
1850: written from the default of "fit.log" in the working directory.
1851:
1852: FIT_SCRIPT
1853: specifies a command that may be executed after an user interrupt. The default
1854: is `replot`, but a `plot` or `load` command may be useful to display a plot
1855: customized to highlight the progress of the fit.
1856: 3 multi-branch
1857: ?commands fit multi-branch
1858: ?fit multi-branch
1859: ?multi-branch
1860: ?branch
1861: In multi-branch fitting, multiple data sets can be simultaneously fit with
1862: functions of one independent variable having common parameters by minimizing
1863: the total WSSR. The function and parameters (branch) for each data set are
1864: selected by using a 'pseudo-variable', e.g., either the dataline number (a
1865: 'column' index of -1) or the datafile index (-2), as the second independent
1866: variable.
1867:
1868: Example: Given two exponential decays of the form, z=f(x), each describing
1869: a different data set but having a common decay time, estimate the values of
1870: the parameters. If the datafile has the format x:z:s, then
1871: f(x,y) = (y==0) ? a*exp(-x/tau) : b*exp(-x/tau)
1872: fit f(x,y) 'datafile' using 1:-1:2:3 via a, b, tau
1873:
1874: For a more complicated example, see the file "hexa.fnc" used by the
1875: "fit.dem" demo.
1876:
1877: Appropriate weighting may be required since unit weights may cause one
1878: branch to predominate if there is a difference in the scale of the dependent
1879: variable. Fitting each branch separately, using the multi-branch solution
1880: as initial values, may give an indication as to the relative effect of each
1881: branch on the joint solution.
1882: 3 starting values
1883: ?commands fit starting_values
1884: ?fit starting_values
1885: ?starting_values
1886: Nonlinear fitting is not guaranteed to converge to the global optimum (the
1887: solution with the smallest sum of squared residuals, SSR), and can get stuck
1888: at a local minimum. The routine has no way to determine that; it is up to
1889: you to judge whether this has happened.
1890:
1891: `fit` may, and often will get "lost" if started far from a solution, where
1892: SSR is large and changing slowly as the parameters are varied, or it may
1893: reach a numerically unstable region (e.g., too large a number causing a
1894: floating point overflow) which results in an "undefined value" message
1895: or `gnuplot` halting.
1896:
1897: To improve the chances of finding the global optimum, you should set the
1898: starting values at least roughly in the vicinity of the solution, e.g.,
1899: within an order of magnitude, if possible. The closer your starting values
1900: are to the solution, the less chance of stopping at another minimum. One way
1901: to find starting values is to plot data and the fitting function on the same
1902: graph and change parameter values and `replot` until reasonable similarity
1903: is reached. The same plot is also useful to check whether the fit stopped at
1904: a minimum with a poor fit.
1905:
1906: Of course, a reasonably good fit is not proof there is not a "better" fit (in
1907: either a statistical sense, characterized by an improved goodness-of-fit
1908: criterion, or a physical sense, with a solution more consistent with the
1909: model.) Depending on the problem, it may be desirable to `fit` with various
1910: sets of starting values, covering a reasonable range for each parameter.
1911: 3 tips
1912: ?commands fit tips
1913: ?fit tips
1914: ?tips
1915: Here are some tips to keep in mind to get the most out of `fit`. They're not
1916: very organized, so you'll have to read them several times until their essence
1917: has sunk in.
1918:
1919: The two forms of the `via` argument to `fit` serve two largely distinct
1920: purposes. The `via "file"` form is best used for (possibly unattended) batch
1921: operation, where you just supply the startup values in a file and can later
1922: use `update` to copy the results back into another (or the same) parameter
1923: file.
1924:
1925: The `via var1, var2, ...` form is best used interactively, where the command
1926: history mechanism may be used to edit the list of parameters to be fitted or
1927: to supply new startup values for the next try. This is particularly useful
1928: for hard problems, where a direct fit to all parameters at once won't work
1929: without good starting values. To find such, you can iterate several times,
1930: fitting only some of the parameters, until the values are close enough to the
1931: goal that the final fit to all parameters at once will work.
1932:
1933: Make sure that there is no mutual dependency among parameters of the function
1934: you are fitting. For example, don't try to fit a*exp(x+b), because
1935: a*exp(x+b)=a*exp(b)*exp(x). Instead, fit either a*exp(x) or exp(x+b).
1936:
1937: A technical issue: the parameters must not be too different in magnitude.
1938: The larger the ratio of the largest and the smallest absolute parameter
1939: values, the slower the fit will converge. If the ratio is close to or above
1940: the inverse of the machine floating point precision, it may take next to
1941: forever to converge, or refuse to converge at all. You will have to adapt
1942: your function to avoid this, e.g., replace 'parameter' by '1e9*parameter' in
1943: the function definition, and divide the starting value by 1e9.
1944:
1945: If you can write your function as a linear combination of simple functions
1946: weighted by the parameters to be fitted, by all means do so. That helps a
1947: lot, because the problem is no longer nonlinear and should converge with only
1948: a small number of iterations, perhaps just one.
1949:
1950: Some prescriptions for analysing data, given in practical experimentation
1951: courses, may have you first fit some functions to your data, perhaps in a
1952: multi-step process of accounting for several aspects of the underlying
1953: theory one by one, and then extract the information you really wanted from
1954: the fitting parameters of those functions. With `fit`, this may often be
1955: done in one step by writing the model function directly in terms of the
1956: desired parameters. Transforming data can also quite often be avoided,
1957: though sometimes at the cost of a more difficult fit problem. If you think
1958: this contradicts the previous paragraph about simplifying the fit function,
1959: you are correct.
1960:
1961: A "singular matrix" message indicates that this implementation of the
1962: Marquardt-Levenberg algorithm can't calculate parameter values for the next
1963: iteration. Try different starting values, writing the function in another
1964: form, or a simpler function.
1965:
1966: Finally, a nice quote from the manual of another fitting package (fudgit),
1967: that kind of summarizes all these issues: "Nonlinear fitting is an art!"
1968: 2 help
1969: ?commands help
1970: ?help
1971: The `help` command displays on-line help. To specify information on a
1972: particular topic use the syntax:
1973:
1974: help {<topic>}
1975:
1976: If <topic> is not specified, a short message is printed about `gnuplot`.
1977: After help for the requested topic is given, a menu of subtopics is given;
1978: help for a subtopic may be requested by typing its name, extending the help
1979: request. After that subtopic has been printed, the request may be extended
1980: again or you may go back one level to the previous topic. Eventually, the
1981: `gnuplot` command line will return.
1982:
1983: If a question mark (?) is given as the topic, the list of topics currently
1984: available is printed on the screen.
1985: 2 if
1986: ?commands if
1987: ?if
1988: The `if` command allows commands to be executed conditionally.
1989:
1990: Syntax:
1991: if (<condition>) <command-line>
1992:
1993: <condition> will be evaluated. If it is true (non-zero), then the command(s)
1994: of the <command-line> will be executed. If <condition> is false (zero), then
1995: the entire <command-line> is ignored. Note that use of `;` to allow multiple
1996: commands on the same line will _not_ end the conditionalized commands.
1997:
1998: Examples:
1999: pi=3
2000: if (pi!=acos(-1)) print "?Fixing pi!"; pi=acos(-1); print pi
2001: will display:
2002: ?Fixing pi!
2003: 3.14159265358979
2004: but
2005: if (1==2) print "Never see this"; print "Or this either"
2006: will not display anything.
2007:
2008: See `reread` for an example of how `if` and `reread` can be used together to
2009: perform a loop.
2010: 2 load
2011: ?commands load
2012: ?load
2013: The `load` command executes each line of the specified input file as if it
2014: had been typed in interactively. Files created by the `save` command can
2015: later be `load`ed. Any text file containing valid commands can be created
2016: and then executed by the `load` command. Files being `load`ed may themselves
2017: contain `load` or `call` commands. See `comment` for information about
2018: comments in commands. To `load` with arguments, see `call`.
2019:
2020: The `load` command _must_ be the last command on a multi-command line.
2021:
2022: Syntax:
2023: load "<input-file>"
2024:
2025: The name of the input file must be enclosed in quotes.
2026:
2027: The special filename "-" may be used to `load` commands from standard input.
2028: This allows a `gnuplot` command file to accept some commands from standard
2029: input. Please see "help batch/interactive" for more details.
2030:
2031: Examples:
2032: load 'work.gnu'
2033: load "func.dat"
2034:
2035: The `load` command is performed implicitly on any file names given as
2036: arguments to `gnuplot`. These are loaded in the order specified, and
2037: then `gnuplot` exits.
2038: 2 pause
2039: ?commands pause
2040: ?pause
2041: The `pause` command displays any text associated with the command and then
2042: waits a specified amount of time or until the carriage return is pressed.
2043: `pause` is especially useful in conjunction with `load` files.
2044:
2045: Syntax:
2046: pause <time> {"<string>"}
2047:
2048: <time> may be any integer constant or expression. Choosing -1 will wait
2049: until a carriage return is hit, zero (0) won't pause at all, and a positive
2050: integer will wait the specified number of seconds. `pause 0` is synonymous
2051: with `print`.
2052:
2053: Note: Since `pause` communicates with the operating system rather than the
2054: graphics, it may behave differently with different device drivers (depending
2055: upon how text and graphics are mixed).
2056:
2057: Examples:
2058: pause -1 # Wait until a carriage return is hit
2059: pause 3 # Wait three seconds
2060: pause -1 "Hit return to continue"
2061: pause 10 "Isn't this pretty? It's a cubic spline."
2062:
2063: 2 plot
2064: ?commands plot
2065: ?plot
2066: `plot` is the primary command for drawing plots with `gnuplot`. It creates
2067: plots of functions and data in many, many ways. `plot` is used to draw 2-d
2068: functions and data; `splot` draws 2-d projections of 3-d surfaces and data.
2069: `plot` and `splot` contain many common features; see `splot` for differences.
2070: Note specifically that `splot`'s `binary` and `matrix` options do not exist
2071: for `plot`.
2072:
2073: Syntax:
2074: plot {<ranges>}
2075: {<function> | {"<datafile>" {datafile-modifiers}}}
2076: {axes <axes>} {<title-spec>} {with <style>}
2077: {, {definitions,} <function> ...}
2078:
2079: where either a <function> or the name of a data file enclosed in quotes is
2080: supplied. A function is a mathematical expression or a pair of mathematical
2081: expressions in parametric mode. The expressions may be defined completely or
2082: in part earlier in the stream of `gnuplot` commands (see `user-defined`).
2083:
2084: It is also possible to define functions and parameters on the `plot` command
2085: itself. This is done merely by isolating them from other items with commas.
2086:
2087: There are four possible sets of axes available; the keyword <axes> is used to
2088: select the axes for which a particular line should be scaled. `x1y1` refers
2089: to the axes on the bottom and left; `x2y2` to those on the top and right;
2090: `x1y2` to those on the bottom and right; and `x2y1` to those on the top and
2091: left. Ranges specified on the `plot` command apply only to the first set of
2092: axes (bottom left).
2093:
2094: Examples:
2095: plot sin(x)
2096: plot f(x) = sin(x*a), a = .2, f(x), a = .4, f(x)
2097: plot [t=1:10] [-pi:pi*2] tan(t), \
2098: "data.1" using (tan($2)):($3/$4) smooth csplines \
2099: axes x1y2 notitle with lines 5
2100:
2101: 3 data-file
2102: ?commands plot datafile
2103: ?plot datafile
2104: ?data-file
2105: ?datafile
2106: ?data
2107: Discrete data contained in a file can be displayed by specifying the name of
2108: the data file (enclosed in single or double quotes) on the `plot` command line.
2109:
2110: Syntax:
2111: plot '<file_name>' {index <index list>}
2112: {every <every list>}
2113: {thru <thru expression>}
2114: {using <using list>}
2115: {smooth <option>}
2116:
2117: The modifiers `index`, `every`, `thru`, `using`, and `smooth` are discussed
2118: separately. In brief, `index` selects which data sets in a multi-data-set
2119: file are to be plotted, `every` specifies which points within a single data
2120: set are to be plotted, `using` determines how the columns within a single
2121: record are to be interpreted (`thru` is a special case of `using`), and
2122: `smooth` allows for simple interpolation and approximation. ('splot' has a
2123: similar syntax, but does not support the `smooth` and `thru` options.)
2124:
2125: Data files should contain at least one data point per record (`using` can
2126: select one data point from the record). Records beginning with `#` (and
2127: also with `!` on VMS) will be treated as comments and ignored. Each data
2128: point represents an (x,y) pair. For `plot`s with error bars (see `set style
2129: errorbars`), each data point is (x,y,ydelta), (x,y,ylow,yhigh), (x,y,xdelta),
2130: (x,y,xlow,xhigh), or (x,y,xlow,xhigh,ylow,yhigh). In all cases, the numbers
2131: on each record of a data file must be separated by white space (one or more
2132: blanks or tabs), unless a format specifier is provided by the `using` option.
2133: This white space divides each record into columns.
2134:
2135: Data may be written in exponential format with the exponent preceded by the
2136: letter e, E, d, D, q, or Q.
2137:
2138: Only one column (the y value) need be provided. If x is omitted, `gnuplot`
2139: provides integer values starting at 0.
2140:
2141: In datafiles, blank records (records with no characters other than blanks and
2142: a newline and/or carriage return) are significant---pairs of blank records
2143: separate `index`es (see `plot datafile index`). Data separated by double
2144: blank records are treated as if they were in separate data files.
2145:
2146: Single blank records designate discontinuities in a `plot`; no line will join
2147: points separated by a blank records (if they are plotted with a line style).
2148:
2149: If autoscaling has been enabled (`set autoscale`), the axes are automatically
2150: extended to include all datapoints, with a whole number of tic marks if tics
2151: are being drawn. This has two consequences: i) For `splot`, the corner of
2152: the surface may not coincide with the corner of the base. In this case, no
2153: vertical line is drawn. ii) When plotting data with the same x range on a
2154: dual-axis graph, the x coordinates may not coincide if the x2tics are not
2155: being drawn. This is because the x axis has been autoextended to a whole
2156: number of tics, but the x2 axis has not. The following example illustrates
2157: the problem:
2158:
2159: reset; plot '-', '-'
2160: 1 1
2161: 19 19
2162: e
2163: 1 1
2164: 19 19
2165: e
2166: 4 every
2167: ?commands plot datafile every
2168: ?plot datafile every
2169: ?plot every
2170: ?data-file every
2171: ?datafile every
2172: ?every
2173: The `every` keyword allows a periodic sampling of a data set to be plotted.
2174:
2175: In the discussion a "point" is a datum defined by a single record in the
2176: file; "block" here will mean the same thing as "datablock" (see `glossary`).
2177:
2178: Syntax:
2179: plot 'file' every {<point_incr>}
2180: {:{<block_incr>}
2181: {:{<start_point>}
2182: {:{<start_block>}
2183: {:{<end_point>}
2184: {:<end_block>}}}}}
2185:
2186: The data points to be plotted are selected according to a loop from
2187: <`start_point`> to <`end_point`> with increment <`point_incr`> and the
2188: blocks according to a loop from <`start_block`> to <`end_block`> with
2189: increment <`block_incr`>.
2190:
2191: The first datum in each block is numbered '0', as is the first block in the
2192: file.
2193:
2194: Note that records containing unplottable information are counted.
2195:
2196: Any of the numbers can be omitted; the increments default to unity, the start
2197: values to the first point or block, and the end values to the last point or
2198: block. If `every` is not specified, all points in all lines are plotted.
2199:
2200: Examples:
2201: every :::3::3 # selects just the fourth block ('0' is first)
2202: every :::::9 # selects the first 10 blocks
2203: every 2:2 # selects every other point in every other block
2204: every ::5::15 # selects points 5 through 15 in each block
2205: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/simple/simple.html">Simple Plot Demos </a>,
2206: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/surfacea/surfacea.html">Non-parametric splot demos </a>, and
2207: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/surfaceb/surfaceb.html">Parametric splot demos.</a>
2208: 4 example datafile
2209: ?commands plot datafile example
2210: ?plot datafile example
2211: ?plot example
2212: ?datafile example
2213: ?data-file example
2214: ?example
2215: This example plots the data in the file "population.dat" and a theoretical
2216: curve:
2217:
2218: pop(x) = 103*exp((1965-x)/10)
2219: plot [1960:1990] 'population.dat', pop(x)
2220:
2221: The file "population.dat" might contain:
2222:
2223: # Gnu population in Antarctica since 1965
2224: 1965 103
2225: 1970 55
2226: 1975 34
2227: 1980 24
2228: 1985 10
2229:
2230: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/population.gif" alt="[population.gif]" width=640 height=480>
2231: 4 index
2232: ?commands plot datafile index
2233: ?plot datafile index
2234: ?plot index
2235: ?data-file index
2236: ?datafile index
2237: ?index
2238: The `index` keyword allows only some of the data sets in a multi-data-set
2239: file to be plotted.
2240:
2241: Syntax:
2242: plot 'file' index <m>{{:<n>}:<p>}
2243:
2244: Data sets are separated by pairs of blank records. `index <m>` selects only
2245: set <m>; `index <m>:<n>` selects sets in the range <m> to <n>; and `index
2246: <m>:<n>:<p>` selects indices <m>, <m>+<p>, <m>+2<p>, etc., but stopping at
2247: <n>. Following C indexing, the index 0 is assigned to the first data set in
2248: the file. Specifying too large an index results in an error message. If
2249: `index` is not specified, all sets are plotted as a single data set.
2250:
2251: Example:
2252: plot 'file' index 4:5
2253: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/multimsh/multimsh.html"> splot with indices demo. </a>
2254: 4 smooth
2255: ?commands plot datafile smooth
2256: ?plot datafile smooth
2257: ?plot smooth
2258: ?data-file smooth
2259: ?datafile smooth
2260: ?smooth
2261: `gnuplot` includes a few general-purpose routines for interpolation and
2262: approximation of data; these are grouped under the `smooth` option. More
2263: sophisticated data processing may be performed by preprocessing the data
2264: externally or by using `fit` with an appropriate model.
2265:
2266: Syntax:
2267: smooth {unique | csplines | acsplines | bezier | sbezier}
2268:
2269: `unique` plots the data after making them monotonic. Each of the other
2270: routines uses the data to determine the coefficients of a continuous curve
2271: between the endpoints of the data. This curve is then plotted in the same
2272: manner as a function, that is, by finding its value at uniform intervals
2273: along the abscissa (see `set samples`) and connecting these points with
2274: straight line segments (if a line style is chosen).
2275:
2276: If `autoscale` is in effect, the ranges will be computed such that the
2277: plotted curve lies within the borders of the graph.
2278:
2279: If too few points are available to allow the selected option to be applied,
2280: an error message is produced. The minimum number is one for `unique`, four
2281: for `acsplines`, and three for the others.
2282:
2283: The `smooth` options have no effect on function plots.
2284: 5 acsplines
2285: ?commands plot datafile smooth acsplines
2286: ?plot datafile smooth acsplines
2287: ?data-file smooth acsplines
2288: ?datafile smooth acsplines
2289: ?plot smooth acsplines
2290: ?plot acsplines
2291: ?smooth acsplines
2292: ?acsplines
2293: The `acsplines` option approximates the data with a "natural smoothing spline".
2294: After the data are made monotonic in x (see `smooth unique`), a curve is
2295: piecewise constructed from segments of cubic polynomials whose coefficients
2296: are found by the weighting the data points; the weights are taken from the
2297: third column in the data file. That default can be modified by the third
2298: entry in the `using` list, e.g.,
2299: plot 'data-file' using 1:2:(1.0) smooth acsplines
2300:
2301: Qualitatively, the absolute magnitude of the weights determines the number
2302: of segments used to construct the curve. If the weights are large, the
2303: effect of each datum is large and the curve approaches that produced by
2304: connecting consecutive points with natural cubic splines. If the weights are
2305: small, the curve is composed of fewer segments and thus is smoother; the
2306: limiting case is the single segment produced by a weighted linear least
2307: squares fit to all the data. The smoothing weight can be expressed in terms
2308: of errors as a statistical weight for a point divided by a "smoothing factor"
2309: for the curve so that (standard) errors in the file can be used as smoothing
2310: weights.
2311:
2312: Example:
2313: sw(x,S)=1/(x*x*S)
2314: plot 'data_file' using 1:2:(sw($3,100)) smooth acsplines
2315: 5 bezier
2316: ?commands plot datafile smooth bezier
2317: ?plot datafile smooth bezier
2318: ?plot smooth bezier
2319: ?data-file smooth bezier
2320: ?datafile smooth bezier
2321: ?plot bezier
2322: ?smooth bezier
2323: ?bezier
2324: The `bezier` option approximates the data with a Bezier curve of degree n
2325: (the number of data points) that connects the endpoints.
2326: 5 csplines
2327: ?commands plot datafile smooth csplines
2328: ?plot datafile smooth csplines
2329: ?plot smooth csplines
2330: ?data-file smooth csplines
2331: ?datafile smooth csplines
2332: ?plot csplines
2333: ?smooth csplines
2334: ?csplines
2335: The `csplines` option connects consecutive points by natural cubic splines
2336: after rendering the data monotonic (see `smooth unique`).
2337: 5 sbezier
2338: ?commands plot datafile smooth sbezier
2339: ?plot datafile smooth sbezier
2340: ?plot smooth sbezier
2341: ?data-file smooth sbezier
2342: ?datafile smooth sbezier
2343: ?plot sbezier
2344: ?smooth sbezier
2345: ?sbezier
2346: The `sbezier` option first renders the data monotonic (`unique`) and then
2347: applies the `bezier` algorithm.
2348: 5 unique
2349: ?commands plot datafile smooth unique
2350: ?plot datafile smooth unique
2351: ?plot smooth unique
2352: ?data-file smooth unique
2353: ?datafile smooth unique
2354: ?plot unique
2355: ?smooth unique
2356: ?unique
2357: The `unique` option makes the data monotonic in x; points with the same
2358: x-value are replaced by a single point having the average y-value. The
2359: resulting points are then connected by straight line segments.
2360: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/mgr/mgr.html"> See demos. </a>
2361: 4 special-filenames
2362: ?commands plot datafile special-filenames
2363: ?plot datafile special-filenames
2364: ?plot special-filenames
2365: ?datafile special-filenames
2366: ?special-filenames
2367: A special filename of `'-'` specifies that the data are inline; i.e., they
2368: follow the command. Only the data follow the command; `plot` options like
2369: filters, titles, and line styles remain on the 'plot' command line. This is
2370: similar to << in unix shell script, and $DECK in VMS DCL. The data are
2371: entered as though they are being read from a file, one data point per record.
2372: The letter "e" at the start of the first column terminates data entry. The
2373: `using` option can be applied to these data---using it to filter them through
2374: a function might make sense, but selecting columns probably doesn't!
2375:
2376: `'-'` is intended for situations where it is useful to have data and commands
2377: together, e.g., when `gnuplot` is run as a sub-process of some front-end
2378: application. Some of the demos, for example, might use this feature. While
2379: `plot` options such as `index` and `every` are recognized, their use forces
2380: you to enter data that won't be used. For example, while
2381:
2382: plot '-' index 0, '-' index 1
2383: 2
2384: 4
2385: 6
2386:
2387:
2388: 10
2389: 12
2390: 14
2391: e
2392: 2
2393: 4
2394: 6
2395:
2396:
2397: 10
2398: 12
2399: 14
2400: e
2401:
2402: does indeed work,
2403:
2404: plot '-', '-'
2405: 2
2406: 4
2407: 6
2408: e
2409: 10
2410: 12
2411: 14
2412: e
2413:
2414: is a lot easier to type.
2415:
2416: If you use `'-'` with `replot`, you may need to enter the data more than once
2417: (see `replot`).
2418:
2419: A blank filename ('') specifies that the previous filename should be reused.
2420: This can be useful with things like
2421:
2422: plot 'a/very/long/filename' using 1:2, '' using 1:3, '' using 1:4
2423:
2424: (If you use both `'-'` and `''` on the same `plot` command, you'll need to
2425: have two sets of inline data, as in the example above.)
2426:
2427: On some computer systems with a popen function (Unix), the datafile can be
2428: piped through a shell command by starting the file name with a '<'. For
2429: example,
2430:
2431: pop(x) = 103*exp(-x/10)
2432: plot "< awk '{print $1-1965, $2}' population.dat", pop(x)
2433:
2434: would plot the same information as the first population example but with
2435: years since 1965 as the x axis. If you want to execute this example, you
2436: have to delete all comments from the data file above or substitute the
2437: following command for the first part of the command above (the part up to
2438: the comma):
2439:
2440: plot "< awk '$0 !~ /^#/ {print $1-1965, $2}' population.dat"
2441:
2442: While this approach is most flexible, it is possible to achieve simple
2443: filtering with the `using` or `thru` keywords.
2444: 4 thru
2445: ?commands plot datafile thru
2446: ?plot datafile thru
2447: ?plot thru
2448: ?data-file thru
2449: ?datafile thru
2450: ?thru
2451: The `thru` function is provided for backward compatibility.
2452:
2453: Syntax:
2454: plot 'file' thru f(x)
2455:
2456: It is equivalent to:
2457:
2458: plot 'file' using 1:(f($2))
2459:
2460: While the latter appears more complex, it is much more flexible. The more
2461: natural
2462:
2463: plot 'file' thru f(y)
2464:
2465: also works (i.e. you can use y as the dummy variable).
2466:
2467: `thru` is parsed for `splot` and `fit` but has no effect.
2468: 4 using
2469: ?commands plot datafile using
2470: ?plot datafile using
2471: ?plot using
2472: ?data-file using
2473: ?datafile using
2474: ?using
2475: The most common datafile modifier is `using`.
2476:
2477: Syntax:
2478: plot 'file' using {<entry> {:<entry> {:<entry> ...}}} {'format'}
2479:
2480: If a format is specified, each datafile record is read using the C library's
2481: 'scanf' function, with the specified format string. Otherwise the record is
2482: read and broken into columns at spaces or tabs. A format cannot be specified
2483: if time-format data is being used (this must be done by `set data time`).
2484:
2485: The resulting array of data is then sorted into columns according to the
2486: entries. Each <entry> may be a simple column number, which selects the
2487: datum, an expression enclosed in parentheses, or empty. The expression can
2488: use $1 to access the first item read, $2 for the second item, and so on. It
2489: can also use `column(x)` and `valid(x)` where x is an arbitrary expression
2490: resulting in an integer. `column(x)` returns the x'th datum; `valid(x)`
2491: tests that the datum in the x'th column is a valid number. A column number
2492: of 0 generates a number increasing (from zero) with each point, and is reset
2493: upon encountering two blank records. A column number of -1 gives the
2494: dataline number, which starts at 0, increments at single blank records, and
2495: is reset at double blank records. A column number of -2 gives the index
2496: number, which is incremented only when two blank records are found. An empty
2497: <entry> will default to its order in the list of entries. For example,
2498: `using ::4` is interpreted as `using 1:2:4`.
2499:
2500: N.B.---the `call` command also uses $'s as a special character. See `call`
2501: for details about how to include a column number in a `call` argument list.
2502:
2503: If the `using` list has but a single entry, that <entry> will be used for y
2504: and the data point number is used for x; for example, "`plot 'file' using 1`"
2505: is identical to "`plot 'file' using 0:1`". If the `using` list has two
2506: entries, these will be used for x and y. Additional entries are usually
2507: errors in x and/or y. See `set style` for details about plotting styles that
2508: make use of error information, and `fit` for use of error information in
2509: curve fitting.
2510:
2511: 'scanf' accepts several numerical specifications but `gnuplot` requires all
2512: inputs to be double-precision floating-point variables, so `lf` is the only
2513: permissible specifier. 'scanf' expects to see white space---a blank, tab
2514: ("\t"), newline ("\n"), or formfeed ("\f")---between numbers; anything else
2515: in the input stream must be explicitly skipped.
2516:
2517: Note that the use of "\t", "\n", or "\f" or requires use of double-quotes
2518: rather than single-quotes.
2519:
2520: Examples:
2521:
2522: This creates a plot of the sum of the 2nd and 3rd data against the first:
2523: (The format string specifies comma- rather than space-separated columns.)
2524: plot 'file' using 1:($2+$3) '%lf,%lf,%lf'
2525:
2526: In this example the data are read from the file "MyData" using a more
2527: complicated format:
2528: plot 'MyData' using "%*lf%lf%*20[^\n]%lf"
2529:
2530: The meaning of this format is:
2531:
2532: %*lf ignore a number
2533: %lf read a double-precision number (x by default)
2534: %*20[^\n] ignore 20 non-newline characters
2535: %lf read a double-precision number (y by default)
2536:
2537: One trick is to use the ternary `?:` operator to filter data:
2538:
2539: plot 'file' using 1:($3>10 ? $2 : 1/0)
2540:
2541: which plots the datum in column two against that in column one provided
2542: the datum in column three exceeds ten. `1/0` is undefined; `gnuplot`
2543: quietly ignores undefined points, so unsuitable points are suppressed.
2544:
2545: In fact, you can use a constant expression for the column number, provided it
2546: doesn't start with an opening parenthesis; constructs like `using
2547: 0+(complicated expression)` can be used. The crucial point is that the
2548: expression is evaluated once if it doesn't start with a left parenthesis, or
2549: once for each data point read if it does.
2550:
2551: If timeseries data are being used, the time can span multiple columns. The
2552: starting column should be specified. Note that the spaces within the time
2553: must be included when calculating starting columns for other data. E.g., if
2554: the first element on a line is a time with an embedded space, the y value
2555: should be specified as column three.
2556:
2557: It should be noted that `plot 'file'`, `plot 'file' using 1:2`, and `plot
2558: 'file' using ($1):($2)` can be subtly different: 1) if `file` has some lines
2559: with one column and some with two, the first will invent x values when they
2560: are missing, the second will quietly ignore the lines with one column, and
2561: the third will store an undefined value for lines with one point (so that in
2562: a plot with lines, no line joins points across the bad point); 2) if a line
2563: contains text at the first column, the first will abort the plot on an error,
2564: but the second and third should quietly skip the garbage.
2565:
2566: In fact, it is often possible to plot a file with lots of lines of garbage at
2567: the top simply by specifying
2568:
2569: plot 'file' using 1:2
2570:
2571: However, if you want to leave text in your data files, it is safer to put the
2572: comment character (#) in the first column of the text lines.
2573: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/using/using.html"> Feeble using demos. </a>
2574: 3 errorbars
2575: ?commands plot errorbars
2576: ?commands splot errorbars
2577: ?plot errorbars
2578: ?splot errorbars
2579: ?errorbars
2580: Error bars are supported for 2-d data file plots by reading one to four
2581: additional columns (or `using` entries); these additional values are used in
2582: different ways by the various errorbar styles.
2583:
2584: In the default situation, `gnuplot` expects to see three, four, or six
2585: numbers on each line of the data file---either
2586:
2587: (x, y, ydelta),
2588: (x, y, ylow, yhigh),
2589: (x, y, xdelta),
2590: (x, y, xlow, xhigh),
2591: (x, y, xdelta, ydelta), or
2592: (x, y, xlow, xhigh, ylow, yhigh).
2593:
2594: The x coordinate must be specified. The order of the numbers must be
2595: exactly as given above, though the `using` qualifier can manipulate the order
2596: and provide values for missing columns. For example,
2597:
2598: plot 'file' with errorbars
2599: plot 'file' using 1:2:(sqrt($1)) with xerrorbars
2600: plot 'file' using 1:2:($1-$3):($1+$3):4:5 with xyerrorbars
2601:
2602: The last example is for a file containing an unsupported combination of
2603: relative x and absolute y errors. The `using` entry generates absolute x min
2604: and max from the relative error.
2605:
2606: The y error bar is a vertical line plotted from (x, ylow) to (x, yhigh).
2607: If ydelta is specified instead of ylow and yhigh, ylow = y - ydelta and
2608: yhigh = y + ydelta are derived. If there are only two numbers on the record,
2609: yhigh and ylow are both set to y. The x error bar is a horizontal line
2610: computed in the same fashion. To get lines plotted between the data points,
2611: `plot` the data file twice, once with errorbars and once with lines (but
2612: remember to use the `notitle` option on one to avoid two entries in the key).
2613:
2614: The error bars have crossbars at each end unless `set bar` is used (see `set
2615: bar` for details).
2616:
2617: If autoscaling is on, the ranges will be adjusted to include the error bars.
2618: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html"> Errorbar demos. </a>
2619:
2620: See `plot using`, `plot with`, and `set style` for more information.
2621: 3 parametric
2622: ?commands plot parametric
2623: ?commands splot parametric
2624: ?plot parametric
2625: ?splot parametric
2626: ?parametric
2627: When in parametric mode (`set parametric`) mathematical expressions must be
2628: given in pairs for `plot` and in triplets for `splot`.
2629:
2630: Examples:
2631: plot sin(t),t**2
2632: splot cos(u)*cos(v),cos(u)*sin(v),sin(u)
2633:
2634: Data files are plotted as before, except any preceding parametric function
2635: must be fully specified before a data file is given as a plot. In other
2636: words, the x parametric function (`sin(t)` above) and the y parametric
2637: function (`t**2` above) must not be interrupted with any modifiers or data
2638: functions; doing so will generate a syntax error stating that the parametric
2639: function is not fully specified.
2640:
2641: Other modifiers, such as `with` and `title`, may be specified only after the
2642: parametric function has been completed:
2643:
2644: plot sin(t),t**2 title 'Parametric example' with linespoints
2645: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/param/param.html"> Parametric Mode Demos. </a>
2646: 3 ranges
2647: ?commands plot ranges
2648: ?commands splot ranges
2649: ?plot ranges
2650: ?splot ranges
2651: ?ranges
2652: The optional ranges specify the region of the graph that will be displayed.
2653:
2654: Syntax:
2655: [{<dummy-var>=}{{<min>}:{<max>}}]
2656: [{{<min>}:{<max>}}]
2657:
2658: The first form applies to the independent variable (`xrange` or `trange`, if
2659: in parametric mode). The second form applies to the dependent variable
2660: `yrange` (and `xrange`, too, if in parametric mode). <dummy-var> is a new
2661: name for the independent variable. (The defaults may be changed with `set
2662: dummy`.) The optional <min> and <max> terms can be constant expressions or *.
2663:
2664: In non-parametric mode, the order in which ranges must be given is `xrange`
2665: and `yrange`.
2666:
2667: In parametric mode, the order for the `plot` command is `trange`, `xrange`,
2668: and `yrange`. The following `plot` command shows setting the `trange` to
2669: [-pi:pi], the `xrange` to [-1.3:1.3] and the `yrange` to [-1:1] for the
2670: duration of the graph:
2671:
2672: plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2
2673:
2674: Note that the x2range and y2range cannot be specified here---`set x2range`
2675: and `set y2range` must be used.
2676:
2677: Ranges are interpreted in the order listed above for the appropriate mode.
2678: Once all those needed are specified, no further ones must be listed, but
2679: unneeded ones cannot be skipped---use an empty range `[]` as a placeholder.
2680:
2681: `*` can be used to allow autoscaling of either of min and max. See also
2682: `set autoscale`.
2683:
2684: Ranges specified on the `plot` or `splot` command line affect only that
2685: graph; use the `set xrange`, `set yrange`, etc., commands to change the
2686: default ranges for future graphs.
2687:
2688: With time data, you must provide the range (in the same manner as the time
2689: appears in the datafile) within quotes. `gnuplot` uses the `timefmt` string
2690: to read the value---see `set timefmt`.
2691:
2692: Examples:
2693:
2694: This uses the current ranges:
2695: plot cos(x)
2696:
2697: This sets the x range only:
2698: plot [-10:30] sin(pi*x)/(pi*x)
2699:
2700: This is the same, but uses t as the dummy-variable:
2701: plot [t = -10 :30] sin(pi*t)/(pi*t)
2702:
2703: This sets both the x and y ranges:
2704: plot [-pi:pi] [-3:3] tan(x), 1/x
2705:
2706: This sets only the y range, and turns off autoscaling on both axes:
2707: plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)
2708:
2709: This sets xmax and ymin only:
2710: plot [:200] [-pi:] exp(sin(x))
2711:
2712: This sets the x range for a timeseries:
2713: set timefmt "%d/%m/%y %H:%M"
2714: plot ["1/6/93 12:00":"5/6/93 12:00"] 'timedata.dat'
2715:
2716: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/ranges/ranges.html"> See Demo. </a>
2717: 3 title
2718: ?commands plot title
2719: ?commands splot title
2720: ?plot title
2721: ?splot title
2722: A line title for each function and data set appears in the key, accompanied
2723: by a sample of the line and/or symbol used to represent it. It can be
2724: changed by using the `title` option.
2725:
2726: Syntax:
2727: title "<title>" | notitle
2728:
2729: where <title> is the new title of the line and must be enclosed in quotes.
2730: The quotes will not be shown in the key. A special character may be given as
2731: a backslash followed by its octal value ("\345"). The tab character "\t" is
2732: understood. Note that backslash processing occurs only for strings enclosed
2733: in double quotes---use single quotes to prevent such processing. The newline
2734: character "\n" is not processed in key entries in either type of string.
2735:
2736: The line title and sample can be omitted from the key by using the keyword
2737: `notitle`. A null title (`title ''`) is equivalent to `notitle`. If only
2738: the sample is wanted, use one or more blanks (`title ' '`).
2739:
2740: By default the line title is the function or file name as it appears on the
2741: `plot` command. If it is a file name, any datafile modifiers specified will
2742: be included in the default title.
2743:
2744: The layout of the key itself (position, title justification, etc.) can be
2745: controlled by `set key`. Please see `set key` for details.
2746:
2747: Examples:
2748:
2749: This plots y=x with the title 'x':
2750: plot x
2751:
2752: This plots x squared with title "x^2" and file "data.1" with title
2753: "measured data":
2754: plot x**2 title "x^2", 'data.1' t "measured data"
2755:
2756: This puts an untitled circular border around a polar graph:
2757: set polar; plot my_function(t), 1 notitle
2758: 3 with
2759: ?commands plot with
2760: ?commands splot with
2761: ?commands plot style
2762: ?commands splot style
2763: ?plot with
2764: ?plot style
2765: ?splot with
2766: ?splot style
2767: ?style
2768: ?with
2769: Functions and data may be displayed in one of a large number of styles.
2770: The `with` keyword provides the means of selection.
2771:
2772: Syntax:
2773: with <style> { {linestyle | ls <line_style>}
2774: | {{linetype | lt <line_type>}
2775: {linewidth | lw <line_width>}
2776: {pointtype | pt <point_type>}
2777: {pointsize | ps <point_size>}} }
2778:
2779: where <style> is either `lines`, `points`, `linespoints`, `impulses`, `dots`,
2780: `steps`, `fsteps`, `histeps`, `errorbars`, `xerrorbars`, `yerrorbars`,
2781: `xyerrorbars`, `boxes`, `boxerrorbars`, `boxxyerrorbars`, `financebars`,
2782: `candlesticks` or `vector`. Some of these styles require additional
2783: information. See `set style <style>` for details of each style.
2784:
2785: Default styles are chosen with the `set function style` and `set data style`
2786: commands.
2787:
2788: By default, each function and data file will use a different line type and
2789: point type, up to the maximum number of available types. All terminal
2790: drivers support at least six different point types, and re-use them, in
2791: order, if more are required. The LaTeX driver supplies an additional six
2792: point types (all variants of a circle), and thus will only repeat after 12
2793: curves are plotted with points. The PostScript drivers (`postscript`)
2794: supplies a total of 64.
2795:
2796: If you wish to choose the line or point type for a single plot, <line_type>
2797: and <point_type> may be specified. These are positive integer constants (or
2798: expressions) that specify the line type and point type to be used for the
2799: plot. Use `test` to display the types available for your terminal.
2800:
2801: You may also scale the line width and point size for a plot by using
2802: <line_width> and <point_size>, which are specified relative to the default
2803: values for each terminal. The pointsize may also be altered globally---see
2804: `set pointsize` for details. But note that both <point_size> as set here and
2805: as set by `set pointsize` multiply the default point size---their effects are
2806: not cumulative. That is, `set pointsize 2; plot x w p ps 3` will use points
2807: three times default size, not six.
2808:
2809: If you have defined specific line type/width and point type/size combinations
2810: with `set linestyle`, one of these may be selected by setting <line_style> to
2811: the index of the desired style.
2812:
2813: The keywords may be abbreviated as indicated.
2814:
2815: Note that the `linewidth` and `pointsize` options are not supported by all
2816: terminals.
2817:
2818: Examples:
2819:
2820: This plots sin(x) with impulses:
2821: plot sin(x) with impulses
2822:
2823: This plots x with points, x**2 with the default:
2824: plot x*y w points, x**2 + y**2
2825:
2826: This plots tan(x) with the default function style, file "data.1" with lines:
2827: plot [ ] [-2:5] tan(x), 'data.1' with l
2828:
2829: This plots "leastsq.dat" with impulses:
2830: plot 'leastsq.dat' w i
2831:
2832: This plots the data file "population" with boxes:
2833: plot 'population' with boxes
2834:
2835: This plots "exper.dat" with errorbars and lines connecting the points
2836: (errorbars require three or four columns):
2837: plot 'exper.dat' w lines, 'exper.dat' notitle w errorbars
2838:
2839: This plots sin(x) and cos(x) with linespoints, using the same line type but
2840: different point types:
2841: plot sin(x) with linesp lt 1 pt 3, cos(x) with linesp lt 1 pt 4
2842:
2843: This plots file "data" with points of type 3 and twice usual size:
2844: plot 'data' with points pointtype 3 pointsize 2
2845:
2846: This plots two data sets with lines differing only by weight:
2847: plot 'd1' t "good" w l lt 2 lw 3, 'd2' t "bad" w l lt 2 lw 1
2848:
2849: See `set style` to change the default styles.
2850: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/styles/styles.html"> Styles demos. </a>
2851: 2 print
2852: ?commands print
2853: ?print
2854: The `print` command prints the value of <expression> to the screen. It is
2855: synonymous with `pause 0`. <expression> may be anything that `gnuplot` can
2856: evaluate that produces a number, or it can be a string.
2857:
2858: Syntax:
2859: print <expression> {, <expression>, ...}
2860:
2861: See `expressions`.
2862: 2 pwd
2863: ?commands pwd
2864: ?pwd
2865: The `pwd` command prints the name of the working directory to the screen.
2866: 2 quit
2867: ?commands quit
2868: ?quit
2869: The `exit` and `quit` commands and END-OF-FILE character will exit `gnuplot`.
2870: Each of these commands will clear the output device (as does the `clear`
2871: command) before exiting.
2872: 2 replot
2873: ?commands replot
2874: ?replot
2875: The `replot` command without arguments repeats the last `plot` or `splot`
2876: command. This can be useful for viewing a plot with different `set` options,
2877: or when generating the same plot for several devices.
2878:
2879: Arguments specified after a `replot` command will be added onto the last
2880: `plot` or `splot` command (with an implied ',' separator) before it is
2881: repeated. `replot` accepts the same arguments as the `plot` and `splot`
2882: commands except that ranges cannot be specified. Thus you can use `replot`
2883: to plot a function against the second axes if the previous command was `plot`
2884: but not if it was `splot`, and similarly you can use `replot` to add a plot
2885: from a binary file only if the previous command was `splot`.
2886:
2887: N.B.---use of
2888:
2889: plot '-' ; ... ; replot
2890:
2891: is not recommended. `gnuplot` does not store the inline data internally, so
2892: since `replot` appends new information to the previous `plot` and then
2893: executes the modified command, the `'-'` from the initial `plot` will expect
2894: to read inline data again.
2895:
2896: Note that `replot` does not work in `multiplot` mode, since it reproduces
2897: only the last plot rather than the entire screen.
2898:
2899: See also `command-line-editing` for ways to edit the last `plot` (`splot`)
2900: command.
2901: 2 reread
2902: ?commands reread
2903: ?reread
2904: The `reread` command causes the current `gnuplot` command file, as specified
2905: by a `load` command or on the command line, to be reset to its starting
2906: point before further commands are read from it. This essentially implements
2907: an endless loop of the commands from the beginning of the command file to
2908: the `reread` command. (But this is not necessarily a disaster---`reread` can
2909: be very useful when used in conjunction with `if`. See `if` for details.)
2910: The `reread` command has no effect if input from standard input.
2911:
2912: Examples:
2913:
2914: Suppose the file "looper" contains the commands
2915: a=a+1
2916: plot sin(x*a)
2917: pause -1
2918: if(a<5) reread
2919: and from within `gnuplot` you submit the commands
2920: a=0
2921: load 'looper'
2922: The result will be four plots (separated by the `pause` message).
2923:
2924: Suppose the file "data" contains six columns of numbers with a total yrange
2925: from 0 to 10; the first is x and the next are five different functions of x.
2926: Suppose also that the file "plotter" contains the commands
2927: c_p = c_p+1
2928: plot "$0" using 1:c_p with lines linetype c_p
2929: if(c_p < n_p) reread
2930: and from within `gnuplot` you submit the commands
2931: n_p=6
2932: c_p=1
2933: set nokey
2934: set yrange [0:10]
2935: set multiplot
2936: call 'plotter' 'data'
2937: set nomultiplot
2938: The result is a single graph consisting of five plots. The yrange must be
2939: set explicitly to guarantee that the five separate graphs (drawn on top of
2940: each other in multiplot mode) will have exactly the same axes. The linetype
2941: must be specified; otherwise all the plots would be drawn with the same type.
2942: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/animate/animate.html"> Reread Animation Demo</a>
2943: 2 reset
2944: ?commands reset
2945: ?reset
2946: The `reset` command causes all options that can be set with the `set`
2947: command to take on their default values. The only exceptions are that the
2948: terminal set with `set term` and the output file set with `set output` are
2949: left unchanged. This command is useful, e.g., to restore the default
2950: settings at the end of a command file, or to return to a defined state after
2951: lots of settings have been changed within a command file. Please refer to
2952: the `set` command to see the default values that the various options take.
2953: 2 save
2954: ?commands save
2955: ?save
2956: The `save` command saves user-defined functions, variables, `set` options,
2957: or all three, plus the last `plot` (`splot`) command to the specified file.
2958:
2959: Syntax:
2960: save {<option>} '<filename>'
2961:
2962: where <option> is `functions`, `variables` or `set`. If no option is used,
2963: `gnuplot` saves functions, variables, `set` options and the last `plot`
2964: (`splot`) command.
2965:
2966: `save`d files are written in text format and may be read by the `load`
2967: command.
2968:
2969: The filename must be enclosed in quotes.
2970:
2971: Examples:
2972: save 'work.gnu'
2973: save functions 'func.dat'
2974: save var 'var.dat'
2975: save set 'options.dat'
2976: 2 set-show
2977: ?commands set
2978: ?commands show
2979: ?set
2980: ?show
2981: ?show all
2982: The `set` command can be used to sets _lots_ of options. No screen is
2983: drawn, however, until a `plot`, `splot`, or `replot` command is given.
2984:
2985: The `show` command shows their settings; `show all` shows all the
2986: settings.
2987:
2988: If a variable contains time/date data, `show` will display it according to
2989: the format currently defined by `set timefmt`, even if that was not in effect
2990: when the variable was initially defined.
2991: 3 angles
2992: ?commands set angles
2993: ?commands show angles
2994: ?set angles
2995: ?show angles
2996: ?angles
2997: ?commands set angles degrees
2998: ?set angles degrees
2999: ?angles degrees
3000: ?degrees
3001: By default, `gnuplot` assumes the independent variable in polar graphs is in
3002: units of radians. If `set angles degrees` is specified before `set polar`,
3003: then the default range is [0:360] and the independent variable has units of
3004: degrees. This is particularly useful for plots of data files. The angle
3005: setting also applies to 3-d mapping as set via the `set mapping` command.
3006:
3007: Syntax:
3008: set angles {degrees | radians}
3009: show angles
3010:
3011: The angle specified in `set grid polar` is also read and displayed in the
3012: units specified by `set angles`.
3013:
3014: `set angles` also affects the arguments of the machine-defined functions
3015: sin(x), cos(x) and tan(x), and the outputs of asin(x), acos(x), atan(x),
3016: atan2(x), and arg(x). It has no effect on the arguments of hyperbolic
3017: functions or Bessel functions. However, the output arguments of inverse
3018: hyperbolic functions of complex arguments are affected; if these functions
3019: are used, `set angles radians` must be in effect to maintain consistency
3020: between input and output arguments.
3021:
3022: x={1.0,0.1}
3023: set angles radians
3024: y=sinh(x)
3025: print y #prints {1.16933, 0.154051}
3026: print asinh(y) #prints {1.0, 0.1}
3027: but
3028: set angles degrees
3029: y=sinh(x)
3030: print y #prints {1.16933, 0.154051}
3031: print asinh(y) #prints {57.29578, 5.729578}
3032: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/poldat/poldat.html"> Polar plot using `set angles`. </a>
3033: 3 arrow
3034: ?commands set arrow
3035: ?commands set noarrow
3036: ?commands show arrow
3037: ?set arrow
3038: ?set noarrow
3039: ?show arrow
3040: ?arrow
3041: ?noarrow
3042: Arbitrary arrows can be placed on a plot using the `set arrow` command.
3043:
3044: Syntax:
3045: set arrow {<tag>} {from <position>} {to <position>} {{no}head}
3046: { {linestyle | ls <line_style>}
3047: | {linetype | lt <line_type>}
3048: {linewidth | lw <line_width} }
3049: set noarrow {<tag>}
3050: show arrow
3051:
3052: <tag> is an integer that identifies the arrow. If no tag is given, the
3053: lowest unused tag value is assigned automatically. The tag can be used to
3054: delete or change a specific arrow. To change any attribute of an existing
3055: arrow, use the `set arrow` command with the appropriate tag and specify the
3056: parts of the arrow to be changed.
3057:
3058: The <position>s are specified by either x,y or x,y,z, and may be preceded by
3059: `first`, `second`, `graph`, or `screen` to select the coordinate system.
3060: Unspecified coordinates default to 0. The endpoints can be specified in
3061: one of four coordinate systems---`first` or `second` axes, `graph` or
3062: `screen`. See `coordinates` for details. A coordinate system specifier
3063: does not carry over from the "from" position to the "to" position. Arrows
3064: outside the screen boundaries are permitted but may cause device errors.
3065:
3066: Specifying `nohead` produces an arrow drawn without a head---a line segment.
3067: This gives you yet another way to draw a line segment on the plot. By
3068: default, arrows have heads.
3069:
3070: The line style may be selected from a user-defined list of line styles (see
3071: `set linestyle`) or may be defined here by providing values for <line_type>
3072: (an index from the default list of styles) and/or <line_width> (which is a
3073: multiplier for the default width).
3074:
3075: Note, however, that if a user-defined line style has been selected, its
3076: properties (type and width) cannot be altered merely by issuing another
3077: `set arrow` command with the appropriate index and `lt` or `lw`.
3078:
3079: Examples:
3080:
3081: To set an arrow pointing from the origin to (1,2) with user-defined style 5,
3082: use:
3083: set arrow to 1,2 ls 5
3084:
3085: To set an arrow from bottom left of plotting area to (-5,5,3), and tag the
3086: arrow number 3, use:
3087: set arrow 3 from graph 0,0 to -5,5,3
3088:
3089: To change the preceding arrow to end at 1,1,1, without an arrow head and
3090: double its width, use:
3091: set arrow 3 to 1,1,1 nohead lw 2
3092:
3093: To draw a vertical line from the bottom to the top of the graph at x=3, use:
3094: set arrow from 3, graph 0 to 3, graph 1 nohead
3095:
3096: To delete arrow number 2, use:
3097: set noarrow 2
3098:
3099: To delete all arrows, use:
3100: set noarrow
3101:
3102: To show all arrows (in tag order), use:
3103: show arrow
3104: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/arrows/arrows.html"> Arrows Demos. </a>
3105: 3 autoscale
3106: ?commands set autoscale
3107: ?commands set noautoscale
3108: ?commands show autoscale
3109: ?set autoscale
3110: ?set noautoscale
3111: ?show autoscale
3112: ?autoscale
3113: ?noautoscale
3114: Autoscaling may be set individually on the x, y or z axis or globally on all
3115: axes. The default is to autoscale all axes.
3116:
3117: Syntax:
3118: set autoscale {<axes>{min|max}}
3119: set noautoscale {<axes>{min|max}}
3120: show autoscale
3121:
3122: where <axes> is either `x`, `y`, `z`, `x2`, `y2` or `xy`. A keyword with
3123: `min` or `max` appended (this cannot be done with `xy`) tells `gnuplot` to
3124: autoscale just the minimum or maximum of that axis. If no keyword is given,
3125: all axes are autoscaled.
3126:
3127: When autoscaling, the axis range is automatically computed and the dependent
3128: axis (y for a `plot` and z for `splot`) is scaled to include the range of the
3129: function or data being plotted.
3130:
3131: If autoscaling of the dependent axis (y or z) is not set, the current y or z
3132: range is used.
3133:
3134: Autoscaling the independent variables (x for `plot` and x,y for `splot`) is a
3135: request to set the domain to match any data file being plotted. If there are
3136: no data files, autoscaling an independent variable has no effect. In other
3137: words, in the absence of a data file, functions alone do not affect the x
3138: range (or the y range if plotting z = f(x,y)).
3139:
3140: Please see `set xrange` for additional information about ranges.
3141:
3142: The behavior of autoscaling remains consistent in parametric mode, (see `set
3143: parametric`). However, there are more dependent variables and hence more
3144: control over x, y, and z axis scales. In parametric mode, the independent or
3145: dummy variable is t for `plot`s and u,v for `splot`s. `autoscale` in
3146: parametric mode, then, controls all ranges (t, u, v, x, y, and z) and allows
3147: x, y, and z to be fully autoscaled.
3148:
3149: Autoscaling works the same way for polar mode as it does for parametric mode
3150: for `plot`, with the extension that in polar mode `set dummy` can be used to
3151: change the independent variable from t (see `set dummy`).
3152:
3153: When tics are displayed on second axes but no plot has been specified for
3154: those axes, x2range and y2range are inherited from xrange and yrange. This
3155: is done _before_ xrange and yrange are autoextended to a whole number of
3156: tics, which can cause unexpected results.
3157:
3158: Examples:
3159:
3160: This sets autoscaling of the y axis (other axes are not affected):
3161: set autoscale y
3162:
3163: This sets autoscaling only for the minimum of the y axis (the maximum of the
3164: y axis and the other axes are not affected):
3165: set autoscale ymin
3166:
3167: This sets autoscaling of the x and y axes:
3168: set autoscale xy
3169:
3170: This sets autoscaling of the x, y, z, x2 and y2 axes:
3171: set autoscale
3172:
3173: This disables autoscaling of the x, y, z, x2 and y2 axes:
3174: set noautoscale
3175:
3176: This disables autoscaling of the z axis only:
3177: set noautoscale z
3178: 4 parametric mode
3179: ?commands set autoscale parametric
3180: ?set autoscale parametric
3181: ?set autoscale t
3182: When in parametric mode (`set parametric`), the xrange is as fully scalable
3183: as the y range. In other words, in parametric mode the x axis can be
3184: automatically scaled to fit the range of the parametric function that is
3185: being plotted. Of course, the y axis can also be automatically scaled just
3186: as in the non-parametric case. If autoscaling on the x axis is not set, the
3187: current x range is used.
3188:
3189: Data files are plotted the same in parametric and non-parametric mode.
3190: However, there is a difference in mixed function and data plots: in
3191: non-parametric mode with autoscaled x, the x range of the datafile controls
3192: the x range of the functions; in parametric mode it has no influence.
3193:
3194: For completeness a last command `set autoscale t` is accepted. However, the
3195: effect of this "scaling" is very minor. When `gnuplot` determines that the
3196: t range would be empty, it makes a small adjustment if autoscaling is true.
3197: Otherwise, `gnuplot` gives an error. Such behavior may, in fact, not be very
3198: useful and the command `set autoscale t` is certainly questionable.
3199:
3200: `splot` extends the above ideas as you would expect. If autoscaling is set,
3201: then x, y, and z ranges are computed and each axis scaled to fit the
3202: resulting data.
3203: 4 polar mode
3204: ?commands set autoscale polar
3205: ?set autoscale polar
3206: ?set autoscale t
3207: When in polar mode (`set polar`), the xrange and the yrange are both found
3208: from the polar coordinates, and thus they can both be automatically scaled.
3209: In other words, in polar mode both the x and y axes can be automatically
3210: scaled to fit the ranges of the polar function that is being plotted.
3211:
3212: When plotting functions in polar mode, the rrange may be autoscaled. When
3213: plotting data files in polar mode, the trange may also be autoscaled. Note
3214: that if the trange is contained within one quadrant, autoscaling will produce
3215: a polar plot of only that single quadrant.
3216:
3217: Explicitly setting one or two ranges but not others may lead to unexpected
3218: results.
3219: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/poldat/poldat.html"> See polar demos </a>
3220: 3 bar
3221: ?commands set bar
3222: ?commands show bar
3223: ?set bar
3224: ?show bar
3225: The `set bar` command controls the tics at the ends of errorbars.
3226:
3227: Syntax:
3228: set bar {small | large | <size>}
3229: show bar
3230:
3231: `small` is a synonym for 0.0, and `large` for 1.0.
3232: The default is 1.0 if no size is given.
3233: 3 bmargin
3234: ?commands set bmargin
3235: ?set bmargin
3236: ?bmargin
3237: The command `set bmargin` sets the size of the bottom margin. Please see
3238: `set margin` for details.
3239: 3 border
3240: ?commands set border
3241: ?commands set noborder
3242: ?commands show border
3243: ?set border
3244: ?set noborder
3245: ?show border
3246: ?border
3247: ?noborder
3248: The `set border` and `set noborder` commands control the display of the graph
3249: borders for the `plot` and `splot` commands.
3250:
3251: Syntax:
3252: set border {<integer> { {linestyle | ls <line_style>}
3253: | {linetype | lt <line_type> }
3254: {linewidth | lw <line_width>} } }
3255: set noborder
3256: show border
3257:
3258: The borders are encoded in a 12-bit integer: the bottom four bits control the
3259: border for `plot` and the sides of the base for `splot`; The next four bits
3260: control the verticals in `splot`; the top four bits control the edges on top
3261: of the `splot`. In detail, the `<integer>` should be the sum of the
3262: appropriate entries from the following table:
3263:
3264: @start table - first is interactive cleartext form
3265: plot border splot splot
3266: Side splot base verticals top
3267: bottom (south) 1 16 256
3268: left (west) 2 32 512
3269: top (north) 4 64 1024
3270: right (east) 8 128 2048
3271: #\begin{tabular}{|cc|ccc|} \hline
3272: #\multicolumn{5}{|c|}{Graph Border Encoding} \\ \hline \hline
3273: # & & \multicolumn{3}{|c|}{Integer value of selection bit} \\ \cline{3-5}
3274: # & & plot border & splot & splot \\
3275: #\multicolumn{2}{|c|}{Side}& splot base & verticals & top \\ \hline
3276: #bottom & (south) & 1 & 16 & 256 \\
3277: #left & (west) & 2 & 32 & 512 \\
3278: #top & (north) & 4 & 64 & 1024 \\
3279: #right & (east) & 8 & 128 & 2048 \\
3280: %c c c c c .
3281: %@plot border@splot@splot
3282: %@splot base@verticals@top
3283: %_
3284: %bottom (south)@1@16@256
3285: %left (west)@2@32@512
3286: %top (north)@4@64@1024
3287: %right (east)@8@128@2048
3288: @end table
3289:
3290: The default is 31, which is all four sides for `plot`, and base and z axis
3291: for `splot`.
3292:
3293: Using the optional <line_style>, <line_type> and <line_width>
3294: specifiers, the way the border lines are drawn can be influenced
3295: (limited by what the current terminal driver supports).
3296:
3297: Various axes or combinations of axes may be added together in the command.
3298:
3299: To have tics on edges other than bottom and left, disable the usual tics and
3300: enable the second axes.
3301:
3302: Examples:
3303:
3304: Draw all borders:
3305: set border
3306:
3307: Draw only the SOUTHWEST borders:
3308: set border 3
3309:
3310: Draw a complete box around a `splot`:
3311: set border 4095
3312:
3313: Draw a partial box, omitting the front vertical:
3314: set border 127+256+512
3315:
3316: Draw only the NORTHEAST borders:
3317: set noxtics; set noytics; set x2tics; set y2tics; set border 12
3318:
3319: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/borders/borders.html"> Borders Demo. </a>
3320: 3 boxwidth
3321: ?commands set boxwidth
3322: ?commands show boxwidth
3323: ?set boxwidth
3324: ?show boxwidth
3325: ?boxwidth
3326: The `set boxwidth` command is used to set the default width of boxes in the
3327: `boxes` and `boxerrorbars` styles.
3328:
3329: Syntax:
3330: set boxwidth {<width>}
3331: show boxwidth
3332:
3333: If a data file is plotted without the width being specified in the third,
3334: fourth, or fifth column (or `using` entry), or if a function is plotted, the
3335: width of each box is set by the `set boxwidth` command. (If a width is given
3336: both in the file and by the `set boxwidth` command, the one in the file is
3337: used.) If the width is not specified in one of these ways, the width of each
3338: box will be calculated automatically so that it touches the adjacent boxes.
3339: In a four-column data set, the fourth column will be interpreted as the box
3340: width unless the width is set to -2.0, in which case the width will be
3341: calculated automatically. See `set style boxerrorbars` for more details.
3342:
3343: To set the box width to automatic use the command
3344: set boxwidth
3345: or, for four-column data,
3346: set boxwidth -2
3347:
3348: The same effect can be achieved with the `using` keyword in `plot`:
3349: plot 'file' using 1:2:3:4:(-2)
3350: 3 clabel
3351: ?commands set clabel
3352: ?commands set noclabel
3353: ?commands show clabel
3354: ?set clabel
3355: ?set noclabel
3356: ?show clabel
3357: ?clabel
3358: ?noclabel
3359: `gnuplot` will vary the linetype used for each contour level when clabel is
3360: set. When this option on (the default), a legend labels each linestyle with
3361: the z level it represents. It is not possible at present to separate the
3362: contour labels from the surface key.
3363:
3364: Syntax:
3365: set clabel {'<format>'}
3366: set noclabel
3367: show clabel
3368:
3369: The default for the format string is %8.3g, which gives three decimal places.
3370: This may produce poor label alignment if the key is altered from its default
3371: configuration.
3372:
3373: The first contour linetype, or only contour linetype when clabel is off, is
3374: the surface linetype +1; contour points are the same style as surface points.
3375:
3376: See also `set contour`.
3377: 3 clip
3378: ?commands set clip
3379: ?commands set noclip
3380: ?commands show clip
3381: ?set clip
3382: ?set noclip
3383: ?show clip
3384: ?clip
3385: ?noclip
3386: `gnuplot` can clip data points and lines that are near the boundaries of a
3387: graph.
3388:
3389: Syntax:
3390: set clip <clip-type>
3391: set noclip <clip-type>
3392: show clip
3393:
3394: Three clip types are supported by `gnuplot`: `points`, `one`, and `two`.
3395: One, two, or all three clip types may be active for a single graph.
3396:
3397: The `points` clip type forces `gnuplot` to clip (actually, not plot at all)
3398: data points that fall within but too close to the boundaries. This is done
3399: so that large symbols used for points will not extend outside the boundary
3400: lines. Without clipping points near the boundaries, the plot may look bad.
3401: Adjusting the x and y ranges may give similar results.
3402:
3403: Setting the `one` clip type causes `gnuplot` to draw a line segment which has
3404: only one of its two endpoints within the graph. Only the in-range portion of
3405: the line is drawn. The alternative is to not draw any portion of the line
3406: segment.
3407:
3408: Some lines may have both endpoints out of range, but pass through the graph.
3409: Setting the `two` clip-type allows the visible portion of these lines to be
3410: drawn.
3411:
3412: In no case is a line drawn outside the graph.
3413:
3414: The defaults are `noclip points`, `clip one`, and `noclip two`.
3415:
3416: To check the state of all forms of clipping, use
3417: show clip
3418:
3419: For backward compatibility with older versions, the following forms are also
3420: permitted:
3421: set clip
3422: set noclip
3423:
3424: `set clip` is synonymous with `set clip points`; `set noclip` turns off all
3425: three types of clipping.
3426: 3 cntrparam
3427: ?commands set cntrparam
3428: ?commands show cntrparam
3429: ?set cntrparam
3430: ?show cntrparam
3431: ?cntrparam
3432: `set cntrparam` controls the generation of contours and their smoothness for
3433: a contour plot. `show contour` displays current settings of `cntrparam` as
3434: well as `contour`.
3435:
3436: Syntax:
3437: set cntrparam { {linear | cubicspline | bspline}
3438: { points <n>} { order <n> }
3439: { levels auto {<n>} | <n>
3440: | discrete <z1> {,<z2>{,<z3>...}}
3441: | incremental <start>, <incr> {,<end>}
3442: }
3443: }
3444: show contour
3445:
3446: This command has two functions. First, it sets the values of z for which
3447: contour points are to be determined (by linear interpolation between data
3448: points or function isosamples.) Second, it controls the way contours are
3449: drawn between the points determined to be of equal z. <n> should be an
3450: integral constant expression and <z1>, <z2> ... any constant expressions.
3451: The parameters are:
3452:
3453: `linear`, `cubicspline`, `bspline`---Controls type of approximation or
3454: interpolation. If `linear`, then straight line segments connect points of
3455: equal z magnitude. If `cubicspline`, then piecewise-linear contours are
3456: interpolated between the same equal z points to form somewhat smoother
3457: contours, but which may undulate. If `bspline`, a guaranteed-smoother curve
3458: is drawn, which only approximates the position of the points of equal-z.
3459:
3460: `points`---Eventually all drawings are done with piecewise-linear strokes.
3461: This number controls the number of line segments used to approximate the
3462: `bspline` or `cubicspline` curve. Number of cubicspline or bspline
3463: segments (strokes) = `points` * number of linear segments.
3464:
3465: `order`---Order of the bspline approximation to be used. The bigger this
3466: order is, the smoother the resulting contour. (Of course, higher order
3467: bspline curves will move further away from the original piecewise linear
3468: data.) This option is relevant for `bspline` mode only. Allowed values are
3469: integers in the range from 2 (linear) to 10.
3470:
3471: `levels`--- Selection of contour levels, controlled by `auto` (default),
3472: `discrete`, `incremental`, and <n>, number of contour levels, limited to
3473: MAX_DISCRETE_LEVELS as defined in plot.h (30 is standard.)
3474:
3475: For `auto`, <n> specifies a nominal number of levels; the actual number will
3476: be adjusted to give simple labels. If the surface is bounded by zmin and zmax,
3477: contours will be generated at integer multiples of dz between zmin and zmax,
3478: where dz is 1, 2, or 5 times some power of ten (like the step between two
3479: tic marks).
3480:
3481: For `levels discrete`, contours will be generated at z = <z1>, <z2> ... as
3482: specified; the number of discrete levels sets the number of contour levels.
3483: In `discrete` mode, any `set cntrparms levels <n>` are ignored.
3484:
3485: For `incremental`, contours are generated at values of z beginning at <start>
3486: and increasing by <increment>, until the number of contours is reached. <end>
3487: is used to determine the number of contour levels, which will be changed by
3488: any subsequent `set cntrparam levels <n>`.
3489:
3490: If the command `set cntrparam` is given without any arguments specified, the
3491: defaults are used: linear, 5 points, order 4, 5 auto levels.
3492:
3493: Examples:
3494: set cntrparam bspline
3495: set cntrparam points 7
3496: set cntrparam order 10
3497:
3498: To select levels automatically, 5 if the level increment criteria are met:
3499: set cntrparam levels auto 5
3500:
3501: To specify discrete levels at .1, .37, and .9:
3502: set cntrparam levels discrete .1,1/exp(1),.9
3503:
3504: To specify levels from 0 to 4 with increment 1:
3505: set cntrparam levels incremental 0,1,4
3506:
3507: To set the number of levels to 10 (changing an incremental end or possibly
3508: the number of auto levels):
3509: set cntrparam levels 10
3510:
3511: To set the start and increment while retaining the number of levels:
3512: set cntrparam levels incremental 100,50
3513:
3514: See also `set contour` for control of where the contours are drawn, and `set
3515: clabel` for control of the format of the contour labels and linetypes.
3516: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/contours/contours.html">Contours Demo</a> and
3517: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/discrete/discrete.html">contours with User Defined Levels.</a>
3518: 3 contour
3519: ?commands set contour
3520: ?commands set nocontour
3521: ?commands show contour
3522: ?set contour
3523: ?set nocontour
3524: ?show contour
3525: ?contour
3526: ?nocontour
3527: `set contour` enables contour drawing for surfaces. This option is available
3528: for `splot` only.
3529:
3530: Syntax:
3531: set contour {base | surface | both}
3532: set nocontour
3533: show contour
3534:
3535: The three options specify where to draw the contours: `base` draws the
3536: contours on the grid base where the x/ytics are placed, `surface` draws the
3537: contours on the surfaces themselves, and `both` draws the contours on both
3538: the base and the surface. If no option is provided, the default is `base`.
3539:
3540: See also `set cntrparam` for the parameters that affect the drawing of
3541: contours, and `set clabel` for control of labelling of the contours.
3542:
3543: The surface can be switched off (see `set surface`), giving a contour-only
3544: graph. Though it is possible to use `set size` to enlarge the plot to fill
3545: the screen, more control over the output format can be obtained by writing
3546: the contour information to a file, and rereading it as a 2-d datafile plot:
3547:
3548: set nosurface
3549: set contour
3550: set cntrparam ...
3551: set term table
3552: set out 'filename'
3553: splot ...
3554: set out
3555: # contour info now in filename
3556: set term <whatever>
3557: plot 'filename'
3558:
3559: In order to draw contours, the data should be organized as "grid data". In
3560: such a file all the points for a single y-isoline are listed, then all the
3561: points for the next y-isoline, and so on. A single blank line (a line
3562: containing no characters other than blank spaces and a carriage return and/or
3563: a line feed) separates one y-isoline from the next. See also `splot datafile`.
3564:
3565: If contours are desired from non-grid data, `set dgrid3d` can be used to
3566: create an appropriate grid. See `set dgrid3d` for more information.
3567: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/contours/contours.html">Contours Demo</a> and
3568: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/discrete/discrete.html">contours with User Defined Levels.</a>
3569: 3 data style
3570: ?commands set data style
3571: ?commands show data style
3572: ?set data style
3573: ?show data style
3574: ?data style
3575: The `set data style` command changes the default plotting style for data
3576: plots.
3577:
3578: Syntax:
3579: set data style <style-choice>
3580: show data style
3581:
3582: See `set style` for the choices. If no choice is given, the choices are
3583: listed. `show data style` shows the current default data plotting style.
3584: 3 dgrid3d
3585: ?commands set dgrid3d
3586: ?commands set nodgrid3d
3587: ?commands show dgrid3d
3588: ?set dgrid3d
3589: ?set nodgrid3d
3590: ?show dgrid3d
3591: ?dgrid3d
3592: ?nodgrid3d
3593: The `set dgrid3d` command enables, and can set parameters for, non-grid
3594: to grid data mapping.
3595:
3596: Syntax:
3597: set dgrid3d {<row_size>} {,{<col_size>} {,<norm>}}
3598: set nodgrid3d
3599: show dgrid3d
3600:
3601: By default `dgrid3d` is disabled. When enabled, 3-d data read from a file
3602: are always treated as a scattered data set. A grid with dimensions derived
3603: from a bounding box of the scattered data and size as specified by the
3604: row/col_size parameters is created for plotting and contouring. The grid
3605: is equally spaced in x (rows) and in y (columns); the z values are computed
3606: as weighted averages of the scattered points' z values.
3607:
3608: The third parameter, norm, controls the weighting: Each data point is
3609: weighted inversely by its distance from the grid point raised to the norm
3610: power. (Actually, the weights are given by the inverse of dx^norm + dy^norm,
3611: where dx and dy are the components of the separation of the grid point from
3612: each data point. For some norms that are powers of two, specifically 4, 8,
3613: and 16, the computation is optimized by using the Euclidean distance in the
3614: weight calculation, (dx^2+dx^2)^norm/2. However, any non-negative integer
3615: can be used.)
3616:
3617: The closer the data point is to a grid point, the more effect it has on
3618: that grid point and the larger the value of norm the less effect more
3619: distant data points have on that grid point.
3620:
3621: The `dgrid3d` option is a simple low pass filter that converts scattered
3622: data to a grid data set. More sophisticated approaches to this problem
3623: exist and should be used to preprocess the data outside `gnuplot` if this
3624: simple solution is found inadequate.
3625:
3626: (The z values are found by weighting all data points, not by interpolating
3627: between nearby data points; also edge effects may produce unexpected and/or
3628: undesired results. In some cases, small norm values produce a grid point
3629: reflecting the average of distant data points rather than a local average,
3630: while large values of norm may produce "steps" with several grid points
3631: having the same value as the closest data point, rather than making a smooth
3632: transition between adjacent data points. Some areas of a grid may be filled
3633: by extrapolation, to an arbitrary boundary condition. The variables are
3634: not normalized; consequently the units used for x and y will affect the
3635: relative weights of points in the x and y directions.)
3636:
3637: Examples:
3638: set dgrid3d 10,10,1 # defaults
3639: set dgrid3d ,,4
3640:
3641: The first specifies that a grid of size 10 by 10 is to be constructed using
3642: a norm value of 1 in the weight computation. The second only modifies the
3643: norm, changing it to 4.
3644: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/scatter/scatter.html"> Dgrid3d Demo.</a>
3645:
3646: 3 dummy
3647: ?commands set dummy
3648: ?commands show dummy
3649: ?set dummy
3650: ?show dummy
3651: ?dummy
3652: The `set dummy` command changes the default dummy variable names.
3653:
3654: Syntax:
3655: set dummy {<dummy-var>} {,<dummy-var>}
3656: show dummy
3657:
3658: By default, `gnuplot` assumes that the independent, or "dummy", variable for
3659: the `plot` command is "t" if in parametric or polar mode, or "x" otherwise.
3660: Similarly the independent variables for the `splot` command are "u" and "v"
3661: in parametric mode (`splot` cannot be used in polar mode), or "x" and "y"
3662: otherwise.
3663:
3664: It may be more convenient to call a dummy variable by a more physically
3665: meaningful or conventional name. For example, when plotting time functions:
3666:
3667: set dummy t
3668: plot sin(t), cos(t)
3669:
3670: At least one dummy variable must be set on the command; `set dummy` by itself
3671: will generate an error message.
3672:
3673: Examples:
3674: set dummy u,v
3675: set dummy ,s
3676:
3677: The second example sets the second variable to s.
3678: 3 encoding
3679: ?commands set encoding
3680: ?commands show encoding
3681: ?set encoding
3682: ?show encoding
3683: ?encoding
3684: The `set encoding` command selects a character encoding. Valid values are
3685: `default`, which tells a terminal to use its default; `iso_8859_1` (known in
3686: the PostScript world as `ISO-Latin1`), which is used on many Unix workstations
3687: and with MS-Windows; `cp850`, for OS/2; and `cp437`, for MS-DOS.
3688:
3689: Syntax:
3690: set encoding {<value>}
3691: show encoding
3692:
3693: Note that encoding is not supported by all terminal drivers and that
3694: the device must be able to produce the desired non-standard characters.
3695: 3 format
3696: ?commands set format
3697: ?commands show format
3698: ?set format
3699: ?show format
3700: ?format
3701: The format of the tic-mark labels can be set with the `set format` command.
3702:
3703: Syntax:
3704: set format {<axes>} {"<format-string>"}
3705: set format {<axes>} {'<format-string>'}
3706: show format
3707:
3708: where <axes> is either `x`, `y`, `z`, `xy`, `x2`, `y2` or nothing (which is
3709: the same as `xy`). The length of the string representing a tic mark (after
3710: formatting with 'printf') is restricted to 100 characters. If the format
3711: string is omitted, the format will be returned to the default "%g". For
3712: LaTeX users, the format "$%g$" is often desirable. If the empty string "" is
3713: used, no label will be plotted with each tic, though the tic mark will still
3714: be plotted. To eliminate all tic marks, use `set noxtics` or `set noytics`.
3715:
3716: Newline (\n) is accepted in the format string. Use double-quotes rather than
3717: single-quotes to enable such interpretation. See also `syntax`.
3718:
3719: The default format for both axes is "%g", but other formats such as "%.2f" or
3720: "%3.0em" are often desirable. Anything accepted by 'printf' when given a
3721: double precision number, and accepted by the terminal, will work. Some other
3722: options have been added. If the format string looks like a floating point
3723: format, then `gnuplot` tries to construct a reasonable format.
3724:
3725: Characters not preceded by "%" are printed verbatim. Thus you can include
3726: spaces and labels in your format string, such as "%g m", which will put " m"
3727: after each number. If you want "%" itself, double it: "%g %%".
3728:
3729: See also `set xtics` for more information about tic labels.
3730: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/electron/electron.html"> See demo. </a>
3731: 4 format specifiers
3732: ?commands set format specifiers
3733: ?set format specifiers
3734: ?format specifiers
3735: ?format_specifiers
3736: The acceptable formats (if not in time/date mode) are:
3737:
3738: @start table - first is interactive cleartext form
3739: Format Explanation
3740: %f floating point notation
3741: %e or %E exponential notation; an "e" or "E" before the power
3742: %g or %G the shorter of %e (or %E) and %f
3743: %x or %X hex
3744: %o or %O octal
3745: %t mantissa to base 10
3746: %l mantissa to base of current logscale
3747: %s mantissa to base of current logscale; scientific power
3748: %T power to base 10
3749: %L power to base of current logscale
3750: %S scientific power
3751: %c character replacement for scientific power
3752: %P multiple of pi
3753: #\begin{tabular}{|cl|} \hline
3754: #\multicolumn{2}{|c|}{Tic-mark label numerical format specifiers}\\
3755: #\hline \hline
3756: #Format & Explanation \\ \hline
3757: #\verb@%f@ & floating point notation \\
3758: #\verb@%e@ or \verb@%E@ & exponential notation; an "e" or "E" before the power \\
3759: #\verb@%g@ or \verb@%G@ & the shorter of \verb@%e@ (or \verb@%E@) and \verb@%f@ \\
3760: #\verb@%x@ or \verb@%X@ & hex \\
3761: #\verb@%o@ or \verb@%O@ & octal \\
3762: #\verb@%t@ & mantissa to base 10 \\
3763: #\verb@%l@ & mantissa to base of current logscale \\
3764: #\verb@%s@ & mantissa to base of current logscale; scientific power \\
3765: #\verb@%T@ & power to base 10 \\
3766: #\verb@%L@ & power to base of current logscale \\
3767: #\verb@%S@ & scientific power \\
3768: #\verb@%c@ & character replacement for scientific power \\
3769: #\verb@%P@ & multiple of pi \\
3770: %c l .
3771: %Format@Explanation
3772: %_
3773: %%f@floating point notation
3774: %%e or %E@exponential notation; an "e" or "E" before the power
3775: %%g or %G@the shorter of %e (or %E) and %f
3776: %%x or %X@hex
3777: %%o or %O@octal
3778: %%t@mantissa to base 10
3779: %%l@mantissa to base of current logscale
3780: %%s@mantissa to base of current logscale; scientific power
3781: %%T@power to base 10
3782: %%L@power to base of current logscale
3783: %%S@scientific power
3784: %%c@character replacement for scientific power
3785: %%P@multiple of pi
3786: %_
3787: @end table
3788:
3789: A 'scientific' power is one such that the exponent is a multiple of three.
3790: Character replacement of scientific powers (`"%c"`) has been implemented
3791: for powers in the range -18 to +18. For numbers outside of this range the
3792: format reverts to exponential.
3793:
3794: Other acceptable modifiers (which come after the "%" but before the format
3795: specifier) are "-", which left-justifies the number; "+", which forces all
3796: numbers to be explicitly signed; "#", which places a decimal point after
3797: floats that have only zeroes following the decimal point; a positive integer,
3798: which defines the field width; "0" (the digit, not the letter) immediately
3799: preceding the field width, which indicates that leading zeroes are to be used
3800: instead of leading blanks; and a decimal point followed by a non-negative
3801: integer, which defines the precision (the minimum number of digits of an
3802: integer, or the number of digits following the decimal point of a float).
3803:
3804: Some releases of 'printf' may not support all of these modifiers but may also
3805: support others; in case of doubt, check the appropriate documentation and
3806: then experiment.
3807:
3808: Examples:
3809: set format y "%t"; set ytics (5,10) # "5.0" and "1.0"
3810: set format y "%s"; set ytics (500,1000) # "500" and "1.0"
3811: set format y "+-12.3f"; set ytics(12345) # "+12345.000 "
3812: set format y "%.2t*10^%+03T"; set ytic(12345)# "1.23*10^+04"
3813: set format y "%s*10^{%S}"; set ytic(12345) # "12.345*10^{3}"
3814: set format y "%s %cg"; set ytic(12345) # "12.345 kg"
3815: set format y "%.0P pi"; set ytic(6.283185) # "2 pi"
3816: set format y "%.0P%%"; set ytic(50) # "50%"
3817:
3818: set log y 2; set format y '%l'; set ytics (1,2,3)
3819: #displays "1.0", "1.0" and "1.5" (since 3 is 1.5 * 2^1)
3820:
3821: There are some problem cases that arise when numbers like 9.999 are printed
3822: with a format that requires both rounding and a power.
3823:
3824: If the data type for the axis is time/date, the format string must contain
3825: valid codes for the 'strftime' function (outside of `gnuplot`, type "man
3826: strftime"). See `set timefmt` for a list of the allowed input format codes.
3827: 4 time/date specifiers
3828: ?commands set format time/date_specifiers
3829: ?set format time/date_specifiers
3830: ?set time/date_specifiers
3831: ?time/date_specifiers
3832: In time/date mode, the acceptable formats are:
3833:
3834: @start table - first is interactive cleartext form
3835: Format Explanation
3836: %a abbreviated name of day of the week
3837: %A full name of day of the week
3838: %b or %h abbreviated name of the month
3839: %B full name of the month
3840: %d day of the month, 1--31
3841: %D shorthand for "%m/%d/%y"
3842: %H or %k hour, 0--24
3843: %I or %l hour, 0--12
3844: %j day of the year, 1--366
3845: %m month, 1--12
3846: %M minute, 0--60
3847: %p "am" or "pm"
3848: %r shorthand for "%I:%M:%S %p"
3849: %R shorthand for %H:%M"
3850: %S second, 0--60
3851: %T shorthand for "%H:%M:%S"
3852: %U week of the year (week starts on Sunday)
3853: %w day of the week, 0--6 (Sunday = 0)
3854: %W week of the year (week starts on Monday)
3855: %y year, 0-99
3856: %Y year, 4-digit
3857: #\begin{tabular}{|cl|} \hline
3858: #\multicolumn{2}{|c|}{Tic-mark label Date/Time Format Specifiers}\\
3859: #\hline \hline
3860: #Format & Explanation \\ \hline
3861: #\verb@%a@ & abbreviated name of day of the week \\
3862: #\verb@%A@ & full name of day of the week \\
3863: #\verb@%b@ or \verb@%h@ & abbreviated name of the month \\
3864: #\verb@%B@ & full name of the month \\
3865: #\verb@%d@ & day of the month, 1--31 \\
3866: #\verb@%D@ & shorthand for \verb@"%m/%d/%y"@ \\
3867: #\verb@%H@ or \verb@%k@ & hour, 0--24 \\
3868: #\verb@%I@ or \verb@%l@ & hour, 0--12 \\
3869: #\verb@%j@ & day of the year, 1--366 \\
3870: #\verb@%m@ & month, 1--12 \\
3871: #\verb@%M@ & minute, 0--60 \\
3872: #\verb@%p@ & "am" or "pm" \\
3873: #\verb@%r@ & shorthand for \verb@"%I:%M:%S %p"@ \\
3874: #\verb@%R@ & shorthand for \verb@%H:%M"@ \\
3875: #\verb@%S@ & second, 0--60 \\
3876: #\verb@%T@ & shorthand for \verb@"%H:%M:%S"@ \\
3877: #\verb@%U@ & week of the year (week starts on Sunday) \\
3878: #\verb@%w@ & day of the week, 0--6 (Sunday = 0) \\
3879: #\verb@%W@ & week of the year (week starts on Monday) \\
3880: #\verb@%y@ & year, 0-99 \\
3881: #\verb@%Y@ & year, 4-digit \\
3882: %c l .
3883: %Format@Explanation
3884: %_
3885: %%a@abbreviated name of day of the week
3886: %%A@full name of day of the week
3887: %%b or %h@abbreviated name of the month
3888: %%B@full name of the month
3889: %%d@day of the month, 1--31
3890: %%D@shorthand for "%m/%d/%y"
3891: %%H or %k@hour, 0--24
3892: %%I or %l@hour, 0--12
3893: %%j@day of the year, 1--366
3894: %%m@month, 1--12
3895: %%M@minute, 0--60
3896: %%p@"am" or "pm"
3897: %%r@shorthand for "%I:%M:%S %p"
3898: %%R@shorthand for %H:%M"
3899: %%S@second, 0--60
3900: %%T@shorthand for "%H:%M:%S"
3901: %%U@week of the year (week starts on Sunday)
3902: %%w@day of the week, 0--6 (Sunday = 0)
3903: %%W@week of the year (week starts on Monday)
3904: %%y@year, 0-99
3905: %%Y@year, 4-digit
3906: %_
3907: @end table
3908:
3909: Except for the non-numerical formats, these may be preceded by a "0" ("zero",
3910: not "oh") to pad the field length with leading zeroes, and a positive digit,
3911: to define the minimum field width (which will be overridden if the specified
3912: width is not large enough to contain the number). There is a 24-character
3913: limit to the length of the printed text; longer strings will be truncated.
3914:
3915: Examples:
3916:
3917: Suppose the text is "76/12/25 23:11:11". Then
3918: set format x # defaults to "12/25/76" \n "23:11"
3919: set format x "%A, %d %b %Y" # "Saturday, 25 Dec 1976"
3920: set format x "%r %d" # "11:11:11 pm 12/25/76"
3921:
3922: Suppose the text is "98/07/06 05:04:03". Then
3923: set format x "%1y/%2m/%3d %01H:%02M:%03S" # "98/ 7/ 6 5:04:003"
3924: 3 function style
3925: ?commands set function style
3926: ?commands show function style
3927: ?set function style
3928: ?show function style
3929: ?function style
3930: The `set function style` command changes the default plotting style for
3931: function plots.
3932:
3933: Syntax:
3934: set function style <style-choice>
3935: show function style
3936:
3937: See `set style` for the choices. If no choice is given, the choices are
3938: listed. `show function style` shows the current default function plotting
3939: style.
3940: 3 functions
3941: ?commands show functions
3942: ?show functions
3943: The `show functions` command lists all user-defined functions and their
3944: definitions.
3945:
3946: Syntax:
3947: show functions
3948:
3949: For information about the definition and usage of functions in `gnuplot`,
3950: please see `expressions`.
3951: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/spline/spline.html"> Splines as User Defined Functions.</a>
3952: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/airfoil/airfoil.html">Use of functions and complex variables for airfoils </a>
3953: 3 grid
3954: ?commands set grid
3955: ?commands set nogrid
3956: ?commands show grid
3957: ?set grid
3958: ?set nogrid
3959: ?show grid
3960: ?grid
3961: ?nogrid
3962: The `set grid` command allows grid lines to be drawn on the plot.
3963:
3964: Syntax:
3965: set grid {{no}{m}xtics} {{no}{m}ytics} {{no}{m}ztics}
3966: {{no}{m}x2tics} {{no}{m}y2tics}
3967: {polar {<angle>}}
3968: { {linestyle <major_linestyle>}
3969: | {linetype | lt <major_linetype>}
3970: {linewidth | lw <major_linewidth>}
3971: { , {linestyle | ls <minor_linestyle>}
3972: | {linetype | lt <minor_linetype>}
3973: {linewidth | lw <minor_linewidth>} } }
3974: set nogrid
3975: show grid
3976:
3977: The grid can be enabled and disabled for the major and/or minor tic
3978: marks on any axis, and the linetype and linewidth can be specified
3979: for major and minor grid lines, also via a predefined linestyle, as
3980: far as the active terminal driver supports this.
3981:
3982: Additionally, a polar grid can be selected for 2-d plots---circles are drawn
3983: to intersect the selected tics, and radial lines are drawn at definable
3984: intervals. (The interval is given in degrees or radians ,depending on the
3985: `set angles` setting.) Note that a polar grid is no longer automatically
3986: generated in polar mode.
3987:
3988: The pertinent tics must be enabled before `set grid` can draw them; `gnuplot`
3989: will quietly ignore instructions to draw grid lines at non-existent tics, but
3990: they will appear if the tics are subsequently enabled.
3991:
3992: If no linetype is specified for the minor gridlines, the same linetype as the
3993: major gridlines is used. The default polar angle is 30 degrees.
3994:
3995: Z grid lines are drawn on the back of the plot. This looks better if a
3996: partial box is drawn around the plot---see `set border`.
3997: 3 hidden3d
3998: ?commands set hidden3d
3999: ?commands set nohidden3d
4000: ?commands show hidden3d
4001: ?set hidden3d
4002: ?set nohidden3d
4003: ?show hidden3d
4004: ?hidden3d
4005: ?nohidden3d
4006: The `set hidden3d` command enables hidden line removal for surface plotting
4007: (see `splot`). Some optional features of the underlying algorithm can also
4008: be controlled using this command.
4009:
4010: Syntax:
4011: set hidden3d {defaults} |
4012: { {{offset <offset>} | {nooffset}}
4013: {trianglepattern <bitpattern>}
4014: {{undefined <level>} | {noundefined}}
4015: {{no}altdiagonal}
4016: {{no}bentover} }
4017: set nohidden3d
4018: show hidden3d
4019:
4020: In contrast to the usual display in gnuplot, hidden line removal actually
4021: treats the given function or data grids as real surfaces that can't be seen
4022: through, so parts behind the surface will be hidden by it. For this to be
4023: possible, the surface needs to have 'grid structure' (see `splot datafile`
4024: about this), and it has to be drawn `with lines` or `with linespoints`.
4025:
4026: When `hidden3d` is set, both the hidden portion of the surface and possibly
4027: its contours drawn on the base (see `set contour`) as well as the grid will
4028: be hidden. Each surface has its hidden parts removed with respect to itself
4029: and to other surfaces, if more than one surface is plotted. Contours drawn
4030: on the surface (`set contour surface`) don't work. Labels and arrows are
4031: always visible and are unaffected. The key is also never hidden by the
4032: surface.
4033:
4034: Functions are evaluated at isoline intersections. The algorithm interpolates
4035: linearly between function points or data points when determining the visible
4036: line segments. This means that the appearance of a function may be different
4037: when plotted with `hidden3d` than when plotted with `nohidden3d` because in
4038: the latter case functions are evaluated at each sample. Please see `set
4039: samples` and `set isosamples` for discussion of the difference.
4040:
4041: The algorithm used to remove the hidden parts of the surfaces has some
4042: additional features controllable by this command. Specifying `defaults` will
4043: set them all to their default settings, as detailed below. If `defaults` is
4044: not given, only explicitly specified options will be influenced: all others
4045: will keep their previous values, so you can turn on/off hidden line removal
4046: via `set {no}hidden3d`, without modifying the set of options you chose.
4047:
4048: The first option, `offset`, influences the linestyle used for lines on the
4049: 'back' side. Normally, they are drawn in a linestyle one index number higher
4050: than the one used for the front, to make the two sides of the surface
4051: distinguishable. You can specify a different line style offset to add
4052: instead of the default 1, by `offset <offset>`. Option `nooffset` stands for
4053: `offset 0`, making the two sides of the surface use the same linestyle.
4054:
4055: Next comes the option `trianglepattern <bitpattern>`. <bitpattern> must be
4056: a number between 0 and 7, interpreted as a bit pattern. Each bit determines
4057: the visibility of one edge of the triangles each surface is split up into.
4058: Bit 0 is for the 'horizontal' edges of the grid, Bit 1 for the 'vertical'
4059: ones, and Bit 2 for the diagonals that split each cell of the original grid
4060: into two triangles. The default pattern is 3, making all horizontal and
4061: vertical lines visible, but not the diagonals. You may want to choose 7 to
4062: see those diagonals as well.
4063:
4064: The `undefined <level>` option lets you decide what the algorithm is to do
4065: with data points that are undefined (missing data, or undefined function
4066: values), or exceed the given x-, y- or z-ranges. Such points can either be
4067: plotted nevertheless, or taken out of the input data set. All surface
4068: elements touching a point that is taken out will be taken out as well, thus
4069: creating a hole in the surface. If <level> = 3, equivalent to option
4070: `noundefined`, no points will be thrown away at all. This may produce all
4071: kinds of problems elsewhere, so you should avoid this. <level> = 2 will
4072: throw away undefined points, but keep the out-of-range ones. <level> = 1,
4073: the default, will get rid of out-of-range points as well.
4074:
4075: By specifying `noaltdiagonal`, you can override the default handling of a
4076: special case can occur if `undefined` is active (i.e. <level> is not 3).
4077: Each cell of the grid-structured input surface will be divided in two
4078: triangles along one of its diagonals. Normally, all these diagonals have
4079: the same orientation relative to the grid. If exactly one of the four cell
4080: corners is excluded by the `undefined` handler, and this is on the usual
4081: diagonal, both triangles will be excluded. However if the default setting
4082: of `altdiagonal` is active, the other diagonal will be chosen for this cell
4083: instead, minimizing the size of the hole in the surface.
4084:
4085: The `bentover` option controls what happens to another special case, this
4086: time in conjunction with the `trianglepattern`. For rather crumply surfaces,
4087: it can happen that the two triangles a surface cell is divided into are seen
4088: from opposite sides (i.e. the original quadrangle is 'bent over'), as
4089: illustrated in the following ASCII art:
4090:
4091: C----B
4092: original quadrangle: A--B displayed quadrangle: |\ |
4093: ("set view 0,0") | /| ("set view 75,75" perhaps) | \ |
4094: |/ | | \ |
4095: C--D | \|
4096: A D
4097:
4098: If the diagonal edges of the surface cells aren't generally made visible by
4099: bit 2 of the <bitpattern> there, the edge CB above wouldn't be drawn at all,
4100: normally, making the resulting display hard to understand. Therefore, the
4101: default option of `bentover` will turn it visible in this case. If you don't
4102: want that, you may choose `nobentover` instead.
4103: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/hidden/hidden.html"> Hidden Line Removal Demo</a> and
4104: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/singulr/singulr.html"> Complex Hidden Line Demo. </a>
4105: 3 isosamples
4106: ?commands set isosamples
4107: ?commands show isosamples
4108: ?set isosamples
4109: ?show isosamples
4110: ?isosamples
4111: The isoline density (grid) for plotting functions as surfaces may be changed
4112: by the `set isosamples` command.
4113:
4114: Syntax:
4115: set isosamples <iso_1> {,<iso_2>}
4116: show isosamples
4117:
4118: Each function surface plot will have <iso_1> iso-u lines and <iso_2> iso-v
4119: lines. If you only specify <iso_1>, <iso_2> will be set to the same value
4120: as <iso_1>. By default, sampling is set to 10 isolines per u or v axis.
4121: A higher sampling rate will produce more accurate plots, but will take longer.
4122: These parameters have no effect on data file plotting.
4123:
4124: An isoline is a curve parameterized by one of the surface parameters while
4125: the other surface parameter is fixed. Isolines provide a simple means to
4126: display a surface. By fixing the u parameter of surface s(u,v), the iso-u
4127: lines of the form c(v) = s(u0,v) are produced, and by fixing the v parameter,
4128: the iso-v lines of the form c(u) = s(u,v0) are produced.
4129:
4130: When a function surface plot is being done without the removal of hidden
4131: lines, `set samples` controls the number of points sampled along each
4132: isoline; see `set samples` and `set hidden3d`. The contour algorithm
4133: assumes that a function sample occurs at each isoline intersection, so
4134: change in `samples` as well as `isosamples` may be desired when changing
4135: the resolution of a function surface/contour.
4136: 3 key
4137: ?commands set key
4138: ?commands set nokey
4139: ?commands show key
4140: ?set key
4141: ?set nokey
4142: ?show key
4143: ?key
4144: ?nokey
4145: ?legend
4146: The `set key` enables a key (or legend) describing plots on a plot.
4147:
4148: The contents of the key, i.e., the names given to each plotted data set and
4149: function and samples of the lines and/or symbols used to represent them, are
4150: determined by the `title` and `with` options of the {`s`}`plot` command.
4151: Please see `plot title` and `plot with` for more information.
4152:
4153: Syntax:
4154: set key { left | right | top | bottom | outside | below
4155: | <position>}
4156: {Left | Right} {{no}reverse}
4157: {samplen <sample_length>} {spacing <vertical_spacing>}
4158: {width <width_increment>}
4159: {title "<text>"}
4160: {{no}box { {linestyle | ls <line_style>}
4161: | {linetype | lt <line_type>}
4162: {linewidth | lw <line_width>}}}
4163: set nokey
4164: show key
4165:
4166: By default the key is placed in the upper right corner of the graph. The
4167: keywords `left`, `right`, `top`, `bottom`, `outside` and `below` may be used
4168: to place the key in the other corners inside the graph or to the right
4169: (outside) or below the graph. They may be given alone or combined.
4170:
4171: Justification of the labels within the key is controlled by `Left` or `Right`
4172: (default is `Right`). The text and sample can be reversed (`reverse`) and a
4173: box can be drawn around the key (`box {...}`) in a specified `linetype`
4174: and `linewidth`, or a user-defined `linestyle`. Note that not all
4175: terminal drivers support linewidth selection, though.
4176:
4177: The length of the sample line can be controlled by `samplen`. The sample
4178: length is computed as the sum of the tic length and <sample_length> times the
4179: character width. `samplen` also affects the positions of point samples in
4180: the key since these are drawn at the midpoint of the sample line, even if it
4181: is not drawn. <sample_length> must be an integer.
4182:
4183: The vertical spacing between lines is controlled by `spacing`. The spacing
4184: is set equal to the product of the pointsize, the vertical tic size, and
4185: <vertical_spacing>. The program will guarantee that the vertical spacing is
4186: no smaller than the character height.
4187:
4188: The <width_increment> is a number of character widths to be added to or
4189: subtracted from the length of the string. This is useful only when you are
4190: putting a box around the key and you are using control characters in the text.
4191: `gnuplot` simply counts the number of characters in the string when computing
4192: the box width; this allows you to correct it.
4193:
4194: A title can be put on the key (`title "<text>"`)---see also `syntax` for the
4195: distinction between text in single- or double-quotes. The key title uses the
4196: same justification as do the plot titles.
4197:
4198: The defaults for `set key` are `right`, `top`, `Right`, `noreverse`, `samplen
4199: 4`, `spacing 1.25`, `title ""`, and `nobox`. The default <linetype> is the
4200: same as that used for the plot borders. Entering `set key` with no options
4201: returns the key to its default configuration.
4202:
4203: The <position> can be a simple x,y,z as in previous versions, but these can
4204: be preceded by one of four keywords (`first`, `second`, `graph`, `screen`)
4205: which selects the coordinate system in which the position is specified. See
4206: `coordinates` for more details.
4207:
4208: The key is drawn as a sequence of lines, with one plot described on each
4209: line. On the right-hand side (or the left-hand side, if `reverse` is
4210: selected) of each line is a representation that attempts to mimic the way the
4211: curve is plotted. On the other side of each line is the text description
4212: (the line title), obtained from the `plot` command. The lines are vertically
4213: arranged so that an imaginary straight line divides the left- and right-hand
4214: sides of the key. It is the coordinates of the top of this line that are
4215: specified with the `set key` command. In a `plot`, only the x and y
4216: coordinates are used to specify the line position. For a `splot`, x, y and
4217: z are all used as a 3-d location mapped using the same mapping as the graph
4218: itself to form the required 2-d screen position of the imaginary line.
4219:
4220: Some or all of the key may be outside of the graph boundary, although this
4221: may interfere with other labels and may cause an error on some devices. If
4222: you use the keywords `outside` or `below`, `gnuplot` makes space for the keys
4223: and the graph becomes smaller. Putting keys outside to the right, they
4224: occupy as few columns as possible, and putting them below, as many columns as
4225: possible (depending of the length of the labels), thus stealing as little
4226: space from the graph as possible.
4227:
4228: When using the TeX or PostScript drivers, or similar drivers where formatting
4229: information is embedded in the string, `gnuplot` is unable to calculate
4230: correctly the width of the string for key positioning. If the key is to be
4231: positioned at the left, it may be convenient to use the combination `set key
4232: left Left reverse`. The box and gap in the grid will be the width of the
4233: literal string.
4234:
4235: If `splot` is being used to draw contours, the contour labels will be listed
4236: in the key. If the alignment of these labels is poor or a different number
4237: of decimal places is desired, the label format can be specified. See `set
4238: clabel` for details.
4239:
4240: Examples:
4241:
4242: This places the key at the default location:
4243: set key
4244:
4245: This disables the key:
4246: set nokey
4247:
4248: This places a key at coordinates 2,3.5,2 in the default (first) coordinate
4249: system:
4250: set key 2,3.5,2
4251:
4252: This places the key below the graph:
4253: set key below
4254:
4255: This places the key in the bottom left corner, left-justifies the text,
4256: gives it a title, and draws a box around it in linetype 3:
4257: set key left bottom Left title 'Legend' box 3
4258: 3 label
4259: ?commands set label
4260: ?commands set nolabel
4261: ?commands show label
4262: ?set label
4263: ?set nolabel
4264: ?show label
4265: ?label
4266: ?nolabel
4267: Arbitrary labels can be placed on the plot using the `set label` command.
4268:
4269: Syntax:
4270: set label {<tag>} {"<label_text>"} {at <position>}
4271: {<justification>} {{no}rotate} {font "<name><,size>"}
4272: set nolabel {<tag>}
4273: show label
4274:
4275: The <position> is specified by either x,y or x,y,z, and may be preceded by
4276: `first`, `second`, `graph`, or `screen` to select the coordinate system.
4277: See `coordinates` for details.
4278:
4279: The tag is an integer that is used to identify the label. If no <tag> is
4280: given, the lowest unused tag value is assigned automatically. The tag can be
4281: used to delete or modify a specific label. To change any attribute of an
4282: existing label, use the `set label` command with the appropriate tag, and
4283: specify the parts of the label to be changed.
4284:
4285: By default, the text is placed flush left against the point x,y,z. To adjust
4286: the way the label is positioned with respect to the point x,y,z, add the
4287: parameter <justification>, which may be `left`, `right` or `center`,
4288: indicating that the point is to be at the left, right or center of the text.
4289: Labels outside the plotted boundaries are permitted but may interfere with
4290: axis labels or other text.
4291:
4292: If `rotate` is given, the label is written vertically (if the terminal can do
4293: so, of course).
4294:
4295: If one (or more) axis is timeseries, the appropriate coordinate should be
4296: given as a quoted time string according to the `timefmt` format string. See
4297: `set xdata` and `set timefmt`.
4298:
4299: The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
4300: a newline.
4301:
4302: Examples:
4303:
4304: To set a label at (1,2) to "y=x", use:
4305: set label "y=x" at 1,2
4306:
4307: To set a Sigma of size 24, from the Symbol font set, at the center of
4308: the graph, use:
4309: set label "S" at graph 0.5,0.5 center font "Symbol,24"
4310:
4311: To set a label "y=x^2" with the right of the text at (2,3,4), and tag the
4312: label as number 3, use:
4313: set label 3 "y=x^2" at 2,3,4 right
4314:
4315: To change the preceding label to center justification, use:
4316: set label 3 center
4317:
4318: To delete label number 2, use:
4319: set nolabel 2
4320:
4321: To delete all labels, use:
4322: set nolabel
4323:
4324: To show all labels (in tag order), use:
4325: show label
4326:
4327: To set a label on a graph with a timeseries on the x axis, use, for example:
4328: set timefmt "%d/%m/%y,%H:%M"
4329: set label "Harvest" at "25/8/93",1
4330: 3 linestyle
4331: ?commands set linestyle
4332: ?commands set nolinestyle
4333: ?commands show linestyle
4334: ?set linestyle
4335: ?set nolinestyle
4336: ?show linestyle
4337: ?linestyle
4338: Each terminal has a default set of line and point types, which can be seen
4339: by using the command `test`. `set linestyle` defines a set of line types
4340: and widths and point types and sizes so that you can refer to them later by
4341: an index instead of repeating all the information at each invocation.
4342:
4343: Syntax:
4344: set linestyle <index> {linetype | lt <line_type>}
4345: {linewidth | lw <line_width>}
4346: {pointtype | pt <point_type>}
4347: {pointsize | ps <point_size>}
4348: set nolinestyle
4349: show linestyle
4350:
4351: The line and point types are taken from the default types for the terminal
4352: currently in use. The line width and point size are multipliers for the
4353: default width and size (but note that <point_size> here is unaffected by
4354: the multiplier given on 'set pointsize').
4355:
4356: The defaults for the line and point types is the index. The defaults for
4357: the width and size are both unity.
4358:
4359: Linestyles created by this mechanism do not replace the default styles;
4360: both may be used.
4361:
4362: Not all terminals support the `linewidth` and `pointsize` features; if
4363: not supported, the option will be ignored.
4364:
4365: Note that this feature is not completely implemented; linestyles defined by
4366: this mechanism may be used with 'plot', 'splot', 'replot', and 'set arrow',
4367: but not by other commands that allow the default index to be used, such as
4368: 'set grid'.
4369:
4370: Example:
4371: Suppose that the default lines for indices 1, 2, and 3 are red, green, and
4372: blue, respectively, and the default point shapes for the same indices are a
4373: square, a cross, and a triangle, respectively. Then
4374:
4375: set linestyle 1 lt 2 lw 2 pt 3 ps 0.5
4376:
4377: defines a new linestyle that is green and twice the default width and a new
4378: pointstyle that is a half-sized triangle. The commands
4379:
4380: set function style lines
4381: plot f(x) lt 3, g(x) ls 1
4382:
4383: will create a plot of f(x) using the default blue line and a plot of g(x)
4384: using the user-defined wide green line. Similarly the commands
4385:
4386: set function style linespoints
4387: plot p(x) lt 1 pt 3, q(x) ls 1
4388:
4389: will create a plot of f(x) using the default triangles connected by a red
4390: line and q(x) using small triangles connected by a green line.
4391: 3 lmargin
4392: ?commands set lmargin
4393: ?set lmargin
4394: ?lmargin
4395: The command `set lmargin` sets the size of the left margin. Please see
4396: `set margin` for details.
4397: 3 locale
4398: ?commands set locale
4399: ?commands show logscale
4400: ?set locale
4401: ?show logscale
4402: ?locale
4403: The `locale` setting determines the language with which `{x,y,z}{d,m}tics`
4404: will write the days and months.
4405:
4406: Syntax:
4407: set locale {"<locale>"}
4408:
4409: <locale> may be any language designation acceptable to your installation.
4410: See your system documentation for the available options. The default value
4411: is determined from the LANG environment variable.
4412: 3 logscale
4413: ?commands set logscale
4414: ?commands set nologscale
4415: ?commands show logscale
4416: ?set logscale
4417: ?set nologscale
4418: ?show logscale
4419: ?logscale
4420: ?nologscale
4421: Log scaling may be set on the x, y, z, x2 and/or y2 axes.
4422:
4423: Syntax:
4424: set logscale <axes> <base>
4425: set nologscale <axes>
4426: show logscale
4427:
4428: where <axes> may be any combinations of `x`, `y`, and `z`, in any order, or
4429: `x2` or `y2` and where <base> is the base of the log scaling. If <base> is
4430: not given, then 10 is assumed. If <axes> is not given, then all axes are
4431: assumed. `set nologscale` turns off log scaling for the specified axes.
4432:
4433: Examples:
4434:
4435: To enable log scaling in both x and z axes:
4436: set logscale xz
4437:
4438: To enable scaling log base 2 of the y axis:
4439: set logscale y 2
4440:
4441: To disable z axis log scaling:
4442: set nologscale z
4443: 3 mapping
4444: ?commands set mapping
4445: ?commands show mapping
4446: ?set mapping
4447: ?show mapping
4448: ?mapping
4449: If data are provided to `splot` in spherical or cylindrical coordinates,
4450: the `set mapping` command should be used to instruct `gnuplot` how to
4451: interpret them.
4452:
4453: Syntax:
4454: set mapping {cartesian | spherical | cylindrical}
4455:
4456: A cartesian coordinate system is used by default.
4457:
4458: For a spherical coordinate system, the data occupy two or three columns (or
4459: `using` entries). The first two are interpreted as the polar and azimuthal
4460: angles theta and phi (in the units specified by `set angles`). The radius r
4461: is taken from the third column if there is one, or is set to unity if there
4462: is no third column. The mapping is:
4463:
4464: x = r * cos(theta) * cos(phi)
4465: y = r * sin(theta) * cos(phi)
4466: z = r * sin(phi)
4467:
4468: Note that this is a "geographic" spherical system, rather than a "polar" one.
4469:
4470: For a cylindrical coordinate system, the data again occupy two or three
4471: columns. The first two are interpreted as theta (in the units specified by
4472: `set angles`) and z. The radius is either taken from the third column or set
4473: to unity, as in the spherical case. The mapping is:
4474:
4475: x = r * cos(theta)
4476: y = r * sin(theta)
4477: z = z
4478:
4479: The effects of `mapping` can be duplicated with the `using` filter on the
4480: `splot` command, but `mapping` may be more convenient if many data files are
4481: to be processed. However even if `mapping` is used, `using` may still be
4482: necessary if the data in the file are not in the required order.
4483:
4484: `mapping` has no effect on `plot`.
4485: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/world/world.html">Mapping Demos.</a>
4486: 3 margin
4487: ?commands set margin
4488: ?commands show margin
4489: ?set margin
4490: ?show margin
4491: ?margin
4492: Normally the margins of a plot are automatically calculated based on tics
4493: and axis labels (and the size of the graph correspondingly adjusted.) These
4494: computed values can be overridden by the `set margin` commands. `show margin`
4495: shows the current settings.
4496:
4497: Syntax:
4498: set bmargin {<margin>}
4499: set lmargin {<margin>}
4500: set rmargin {<margin>}
4501: set tmargin {<margin>}
4502: show margin
4503:
4504: The units of <margin> are character heights or widths, as appropriate. A
4505: positive value defines the absolute size of the margin. A negative value
4506: (or none) causes `gnuplot` to revert to the computed value.
4507: 3 missing
4508: ?commands set missing
4509: ?set missing
4510: ?missing
4511: The `set missing` command allows you to tell `gnuplot` what character is
4512: used in a data file to denote missing data.
4513:
4514: Syntax:
4515: set missing {"<character>"}
4516: show missing
4517:
4518: Example:
4519: set missing "?"
4520:
4521: would mean that, when plotting a file containing
4522:
4523: 1 1
4524: 2 ?
4525: 3 2
4526:
4527: the middle line would be ignored.
4528:
4529: There is no default character for `missing`.
4530: 3 multiplot
4531: ?commands set multiplot
4532: ?commands set nomultiplot
4533: ?set multiplot
4534: ?set nomultiplot
4535: ?multiplot
4536: ?nomultiplot
4537: The command `set multiplot` places `gnuplot` in the multiplot mode, in which
4538: several plots are placed on the same page, window, or screen.
4539:
4540: Syntax:
4541: set multiplot
4542: set nomultiplot
4543:
4544: For some terminals, no plot is displayed until the command `set nomultiplot`
4545: is given, which causes the entire page to be drawn and then returns `gnuplot`
4546: to its normal single-plot mode. For other terminals, each separate `plot`
4547: command produces a plot, but the screen may not be cleared between plots.
4548:
4549: Any labels or arrows that have been defined will be drawn for each plot
4550: according to the current size and origin (unless their coordinates are
4551: defined in the `screen` system). Just about everything else that can be
4552: `set` is applied to each plot, too. If you want something to appear only
4553: once on the page, for instance a single time stamp, you'll need to put a `set
4554: time`/`set notime` pair around one of the `plot`, `splot` or `replot`
4555: commands within the `set multiplot`/`set nomultiplot` block.
4556:
4557: The commands `set origin` and `set size` must be used to correctly position
4558: each plot; see `set origin` and `set size` for details of their usage.
4559:
4560: Example:
4561: set size 0.7,0.7
4562: set origin 0.1,0.1
4563: set multiplot
4564: set size 0.4,0.4
4565: set origin 0.1,0.1
4566: plot sin(x)
4567: set size 0.2,0.2
4568: set origin 0.5,0.5
4569: plot cos(x)
4570: set nomultiplot
4571:
4572: displays a plot of cos(x) stacked above a plot of sin(x). Note the initial
4573: `set size` and `set origin`. While these are not always required, their
4574: inclusion is recommended. Some terminal drivers require that bounding box
4575: information be available before any plots can be made, and the form given
4576: above guarantees that the bounding box will include the entire plot array
4577: rather than just the bounding box of the first plot.
4578:
4579: `set size` and `set origin` refer to the entire plotting area used for each
4580: plot. If you want to have the axes themselves line up, you can guarantee
4581: that the margins are the same size with the `set margin` commands. See
4582: `set margin` for their use. Note that the margin settings are absolute,
4583: in character units, so the appearance of the graph in the remaining space
4584: will depend on the screen size of the display device, e.g., perhaps quite
4585: different on a video display and a printer.
4586: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/multiplot/multiplt.html"> See demo. </a>
4587: 3 mx2tics
4588: ?commands set mx2tics
4589: ?commands set nomx2tics
4590: ?commands show mx2tics
4591: ?set mx2tics
4592: ?set nomx2tics
4593: ?show mx2tics
4594: ?mx2tics
4595: ?nomx2tics
4596: Minor tic marks along the x2 (top) axis are controlled by `set mx2tics`.
4597: Please see `set mxtics`.
4598: 3 mxtics
4599: ?commands set mxtics
4600: ?commands set nomxtics
4601: ?commands show mxtics
4602: ?set mxtics
4603: ?set nomxtics
4604: ?show mxtics
4605: ?mxtics
4606: ?nomxtics
4607: Minor tic marks along the x axis are controlled by `set mxtics`. They can be
4608: turned off with `set nomxtics`. Similar commands control minor tics along
4609: the other axes.
4610:
4611: Syntax:
4612: set mxtics {<freq> | default}
4613: set nomxtics
4614: show mxtics
4615:
4616: The same syntax applies to `mytics`, `mztics`, `mx2tics` and `my2tics`.
4617:
4618: <freq> is the number of sub-intervals (NOT the number of minor tics) between
4619: major tics (ten is the default for a linear axis, so there are nine minor
4620: tics between major tics). Selecting `default` will return the number of minor
4621: ticks to its default value.
4622:
4623: If the axis is logarithmic, the number of sub-intervals will be set to a
4624: reasonable number by default (based upon the length of a decade). This will
4625: be overridden if <freq> is given. However the usual minor tics (2, 3, ...,
4626: 8, 9 between 1 and 10, for example) are obtained by setting <freq> to 10,
4627: even though there are but nine sub-intervals.
4628:
4629: Minor tics can be used only with uniformly spaced major tics. Since major
4630: tics can be placed arbitrarily by `set {x|x2|y|y2|z}tics`, minor tics cannot
4631: be used if major tics are explicitly `set`.
4632:
4633: By default, minor tics are off for linear axes and on for logarithmic axes.
4634: They inherit the settings for `axis|border` and `{no}mirror` specified for
4635: the major tics. Please see `set xtics` for information about these.
4636: 3 my2tics
4637: ?commands set my2tics
4638: ?commands set nomy2tics
4639: ?commands show my2tics
4640: ?set my2tics
4641: ?set nomy2tics
4642: ?show my2tics
4643: ?my2tics
4644: ?nomy2tics
4645: Minor tic marks along the y2 (right-hand) axis are controlled by `set
4646: my2tics`. Please see `set mxtics`.
4647: 3 mytics
4648: ?commands set mytics
4649: ?commands set nomytics
4650: ?commands show mytics
4651: ?set mytics
4652: ?set nomytics
4653: ?show mytics
4654: ?mytics
4655: ?nomytics
4656: Minor tic marks along the y axis are controlled by `set mytics`. Please
4657: see `set mxtics`.
4658: 3 mztics
4659: ?commands set mztics
4660: ?commands set nomztics
4661: ?commands show mztics
4662: ?set mztics
4663: ?set nomztics
4664: ?show mztics
4665: ?mztics
4666: ?nomztics
4667: Minor tic marks along the z axis are controlled by `set mztics`. Please
4668: see `set mxtics`.
4669: 3 offsets
4670: ?commands set offsets
4671: ?commands set nooffsets
4672: ?commands show offsets
4673: ?set offsets
4674: ?set nooffsets
4675: ?show offsets
4676: ?offsets
4677: ?nooffsets
4678: Offsets provide a mechanism to put a boundary around the data inside of an
4679: autoscaled graph.
4680:
4681: Syntax:
4682: set offsets <left>, <right>, <top>, <bottom>
4683: set nooffsets
4684: show offsets
4685:
4686: Each offset may be a constant or an expression. Each defaults to 0. Left
4687: and right offsets are given in units of the x axis, top and bottom offsets in
4688: units of the y axis. A positive offset expands the graph in the specified
4689: direction, e.g., a positive bottom offset makes ymin more negative. Negative
4690: offsets, while permitted, can have unexpected interactions with autoscaling
4691: and clipping.
4692:
4693: Offsets are ignored in `splot`s.
4694:
4695: Example:
4696: set offsets 0, 0, 2, 2
4697: plot sin(x)
4698:
4699: This graph of sin(x) will have a y range [-3:3] because the function
4700: will be autoscaled to [-1:1] and the vertical offsets are each two.
4701: 3 origin
4702: ?commands set origin
4703: ?commands show origin
4704: ?set origin
4705: ?show origin
4706: ?origin
4707: The `set origin` command is used to specify the origin of a plotting surface
4708: (i.e., the graph and its margins) on the screen. The coordinates are given
4709: in the `screen` coordinate system (see `coordinates` for information about
4710: this system).
4711:
4712: Syntax:
4713: set origin <x-origin>,<y-origin>
4714: 3 output
4715: ?commands set output
4716: ?commands show output
4717: ?set output
4718: ?show output
4719: ?output
4720: By default, screens are displayed to the standard output. The `set output`
4721: command redirects the display to the specified file or device.
4722:
4723: Syntax:
4724: set output {"<filename>"}
4725: show output
4726:
4727: The filename must be enclosed in quotes. If the filename is omitted, any
4728: output file opened by a previous invocation of `set output` will be closed
4729: and new output will be sent to STDOUT. (If you give the command `set output
4730: "STDOUT"`, your output may be sent to a file named "STDOUT"! ["May be", not
4731: "will be", because some terminals, like `x11`, ignore `set output`.])
4732:
4733: MSDOS users should note that the \ character has special significance in
4734: double-quoted strings, so single-quotes should be used for filenames in
4735: different directories.
4736:
4737: When both `set terminal` and `set output` are used together, it is safest to
4738: give `set terminal` first, because some terminals set a flag which is needed
4739: in some operating systems. This would be the case, for example, if the
4740: operating system needs to know whether or not a file is to be formatted in
4741: order to open it properly.
4742:
4743: On machines with popen functions (Unix), output can be piped through a shell
4744: command if the first non-whitespace character of the filename is '|'.
4745: For instance,
4746:
4747: set output "|lpr -Plaser filename"
4748: set output "|lp -dlaser filename"
4749:
4750: On MSDOS machines, `set output "PRN"` will direct the output to the default
4751: printer. On VMS, output can be sent directly to any spooled device. It is
4752: also possible to send the output to DECnet transparent tasks, which allows
4753: some flexibility.
4754: 3 parametric
4755: ?commands set parametric
4756: ?commands set noparametric
4757: ?commands show parametric
4758: ?set parametric
4759: ?set noparametric
4760: ?show parametric
4761: ?parametric
4762: ?noparametric
4763: The `set parametric` command changes the meaning of `plot` (`splot`) from
4764: normal functions to parametric functions. The command `set noparametric`
4765: restores the plotting style to normal, single-valued expression plotting.
4766:
4767: Syntax:
4768: set parametric
4769: set noparametric
4770: show parametric
4771:
4772: For 2-d plotting, a parametric function is determined by a pair of parametric
4773: functions operating on a parameter. An example of a 2-d parametric function
4774: would be `plot sin(t),cos(t)`, which draws a circle (if the aspect ratio is
4775: set correctly---see `set size`). `gnuplot` will display an error message if
4776: both functions are not provided for a parametric `plot`.
4777:
4778: For 3-d plotting, the surface is described as x=f(u,v), y=g(u,v), z=h(u,v).
4779: Therefore a triplet of functions is required. An example of a 3-d parametric
4780: function would be `cos(u)*cos(v),cos(u)*sin(v),sin(u)`, which draws a sphere.
4781: `gnuplot` will display an error message if all three functions are not
4782: provided for a parametric `splot`.
4783:
4784: The total set of possible plots is a superset of the simple f(x) style plots,
4785: since the two functions can describe the x and y values to be computed
4786: separately. In fact, plots of the type t,f(t) are equivalent to those
4787: produced with f(x) because the x values are computed using the identity
4788: function. Similarly, 3-d plots of the type u,v,f(u,v) are equivalent to
4789: f(x,y).
4790:
4791: Note that the order the parametric functions are specified is xfunction,
4792: yfunction (and zfunction) and that each operates over the common parametric
4793: domain.
4794:
4795: Also, the `set parametric` function implies a new range of values. Whereas
4796: the normal f(x) and f(x,y) style plotting assume an xrange and yrange (and
4797: zrange), the parametric mode additionally specifies a trange, urange, and
4798: vrange. These ranges may be set directly with `set trange`, `set urange`,
4799: and `set vrange`, or by specifying the range on the `plot` or `splot`
4800: commands. Currently the default range for these parametric variables is
4801: [-5:5]. Setting the ranges to something more meaningful is expected.
4802: 3 pointsize
4803: ?commands set pointsize
4804: ?commands show pointsize
4805: ?set pointsize
4806: ?show pointsize
4807: ?pointsize
4808: The `set pointsize` command scales the size of the points used in plots.
4809:
4810: Syntax:
4811: set pointsize <multiplier>
4812: show pointsize
4813:
4814: The default is a multiplier of 1.0. Larger pointsizes may be useful to
4815: make points more visible in bitmapped graphics.
4816:
4817: The pointsize of a single plot may be changed on the `plot` command. See
4818: `plot with` for details.
4819:
4820: Please note that the pointsize setting is not supported by all terminal
4821: types.
4822: 3 polar
4823: ?commands set polar
4824: ?commands set nopolar
4825: ?commands show polar
4826: ?set polar
4827: ?set nopolar
4828: ?show polar
4829: ?polar
4830: ?nopolar
4831: The `set polar` command changes the meaning of the plot from rectangular
4832: coordinates to polar coordinates.
4833:
4834: Syntax:
4835: set polar
4836: set nopolar
4837: show polar
4838:
4839: There have been changes made to polar mode in version 3.7, so that scripts
4840: for `gnuplot` versions 3.5 and earlier will require modification. The main
4841: change is that the dummy variable t is used for the angle so that the x and
4842: y ranges can be controlled independently. Other changes are:
4843: 1) tics are no longer put along the zero axes automatically
4844: ---use `set xtics axis nomirror`; `set ytics axis nomirror`;
4845: 2) the grid, if selected, is not automatically polar
4846: ---use `set grid polar`;
4847: 3) the grid is not labelled with angles
4848: ---use `set label` as necessary.
4849:
4850: In polar coordinates, the dummy variable (t) is an angle. The default range
4851: of t is [0:2*pi], or, if degree units have been selected, to [0:360] (see
4852: `set angles`).
4853:
4854: The command `set nopolar` changes the meaning of the plot back to the default
4855: rectangular coordinate system.
4856:
4857: The `set polar` command is not supported for `splot`s. See the `set mapping`
4858: command for similar functionality for `splot`s.
4859:
4860: While in polar coordinates the meaning of an expression in t is really
4861: r = f(t), where t is an angle of rotation. The trange controls the domain
4862: (the angle) of the function, and the x and y ranges control the range of the
4863: graph in the x and y directions. Each of these ranges, as well as the
4864: rrange, may be autoscaled or set explicitly. See `set xrange` for details
4865: of all the `set range` commands.
4866:
4867: Example:
4868: set polar
4869: plot t*sin(t)
4870: plot [-2*pi:2*pi] [-3:3] [-3:3] t*sin(t)
4871:
4872: The first `plot` uses the default polar angular domain of 0 to 2*pi. The
4873: radius and the size of the graph are scaled automatically. The second `plot`
4874: expands the domain, and restricts the size of the graph to [-3:3] in both
4875: directions.
4876:
4877: You may want to `set size square` to have `gnuplot` try to make the aspect
4878: ratio equal to unity, so that circles look circular.
4879: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/polar/polar.html">Polar demos </a>
4880: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/poldat/poldat.html">Polar Data Plot. </a>
4881: 3 rmargin
4882: ?commands set rmargin
4883: ?set rmargin
4884: ?rmargin
4885: The command `set rmargin` sets the size of the right margin. Please see
4886: `set margin` for details.
4887: 3 rrange
4888: ?commands set rrange
4889: ?commands show rrange
4890: ?set rrange
4891: ?show rrange
4892: ?rrange
4893: The `set rrange` command sets the range of the radial coordinate for a
4894: graph in polar mode. Please see `set xrange` for details.
4895: 3 samples
4896: ?commands set samples
4897: ?commands show samples
4898: ?set samples
4899: ?show samples
4900: ?samples
4901: The sampling rate of functions, or for interpolating data, may be changed
4902: by the `set samples` command.
4903:
4904: Syntax:
4905: set samples <samples_1> {,<samples_2>}
4906: show samples
4907:
4908: By default, sampling is set to 100 points. A higher sampling rate will
4909: produce more accurate plots, but will take longer. This parameter has no
4910: effect on data file plotting unless one of the interpolation/approximation
4911: options is used. See `plot smooth` re 2-d data and `set cntrparam` and
4912: `set dgrid3d` re 3-d data.
4913:
4914: When a 2-d graph is being done, only the value of <samples_1> is relevant.
4915:
4916: When a surface plot is being done without the removal of hidden lines, the
4917: value of samples specifies the number of samples that are to be evaluated for
4918: the isolines. Each iso-v line will have <sample_1> samples and each iso-u
4919: line will have <sample_2> samples. If you only specify <samples_1>,
4920: <samples_2> will be set to the same value as <samples_1>. See also `set
4921: isosamples`.
4922: 3 size
4923: ?commands set size
4924: ?commands show size
4925: ?set size
4926: ?show size
4927: ?size
4928: The `set size` command scales the displayed size of the plot.
4929:
4930: Syntax:
4931: set size {{no}square | ratio <r> | noratio} {<xscale>,<yscale>}
4932: show size
4933:
4934: The <xscale> and <yscale> values are the scaling factors for the size of the
4935: plot, which includes the graph and the margins.
4936:
4937: `ratio` causes `gnuplot` to try to create a graph with an aspect ratio of <r>
4938: (the ratio of the y-axis length to the x-axis length) within the portion of
4939: the plot specified by <xscale> and <yscale>.
4940:
4941: The meaning of a negative value for <r> is different. If <r>=-1, gnuplot
4942: tries to set the scales so that the unit has the same length on both the x
4943: and y axes (suitable for geographical data, for instance). If <r>=-2, the
4944: unit on y has twice the length of the unit on x, and so on.
4945:
4946: The success of `gnuplot` in producing the requested aspect ratio depends on
4947: the terminal selected. The graph area will be the largest rectangle of
4948: aspect ratio <r> that will fit into the specified portion of the output
4949: (leaving adequate margins, of course).
4950:
4951: `square` is a synonym for `ratio 1`.
4952:
4953: Both `noratio` and `nosquare` return the graph to the default aspect ratio
4954: of the terminal, but do not return <xscale> or <yscale> to their default
4955: values (1.0).
4956:
4957: `ratio` and `square` have no effect on 3-d plots.
4958:
4959: `set size` is relative to the default size, which differs from terminal to
4960: terminal. Since `gnuplot` fills as much of the available plotting area as
4961: possible by default, it is safer to use `set size` to decrease the size of
4962: a plot than to increase it. See `set terminal` for the default sizes.
4963:
4964: On some terminals, changing the size of the plot will result in text being
4965: misplaced.
4966:
4967: Examples:
4968:
4969: To set the size to normal size use:
4970: set size 1,1
4971:
4972: To make the graph half size and square use:
4973: set size square 0.5,0.5
4974:
4975: To make the graph twice as high as wide use:
4976: set size ratio 2
4977:
4978: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/airfoil/airfoil.html"> See demo. </a>
4979: 3 style
4980: ?commands set function style
4981: ?commands show function style
4982: ?commands set data style
4983: ?commands show data style
4984: ?set function style
4985: ?show function style
4986: ?set data style
4987: ?show data style
4988: ?set style
4989: ?show style
4990: Default styles are chosen with the `set function style` and `set data style`
4991: commands. See `plot with` for information about how to override the default
4992: plotting style for individual functions and data sets.
4993:
4994: Syntax:
4995: set function style <style>
4996: set data style <style>
4997: show function style
4998: show data style
4999:
5000: The types used for all line and point styles (i.e., solid, dash-dot, color,
5001: etc. for lines; circles, squares, crosses, etc. for points) will be either
5002: those specified on the `plot` or `splot` command or will be chosen
5003: sequentially from the types available to the terminal in use. Use the
5004: command `test` to see what is available.
5005:
5006: None of the styles requiring more than two columns of information (e.g.,
5007: `errorbars`) can be used with `splot`s or function `plot`s. Neither `boxes`
5008: nor any of the `steps` styles can be used with `splot`s. If an inappropriate
5009: style is specified, it will be changed to `points`.
5010:
5011: For 2-d data with more than two columns, `gnuplot` is picky about the allowed
5012: `errorbar` styles. The `using` option on the `plot` command can be used to
5013: set up the correct columns for the style you want. (In this discussion,
5014: "column" will be used to refer both to a column in the data file and an entry
5015: in the `using` list.)
5016:
5017: For three columns, only `xerrorbars`, `yerrorbars` (or `errorbars`), `boxes`,
5018: and `boxerrorbars` are allowed. If another plot style is used, the style
5019: will be changed to `yerrorbars`. The `boxerrorbars` style will calculate the
5020: boxwidth automatically.
5021:
5022: For four columns, only `xerrorbars`, `yerrorbars` (or `errorbars`),
5023: `xyerrorbars`, `boxxyerrorbars`, and `boxerrorbars` are allowed. An illegal
5024: style will be changed to `yerrorbars`.
5025:
5026: Five-column data allow only the `boxerrorbars`, `financebars`, and
5027: `candlesticks` styles. (The last two of these are primarily used for plots
5028: of financial prices.) An illegal style will be changed to `boxerrorbars`
5029: before plotting.
5030:
5031: Six- and seven-column data only allow the `xyerrorbars` and `boxxyerrorbars`
5032: styles. Illegal styles will be changed to `xyerrorbars` before plotting.
5033:
5034: For more information about error bars, please see `plot errorbars`.
5035: 4 boxerrorbars
5036: ?commands set style boxerrorbars
5037: ?set style boxerrorbars
5038: ?style boxerrorbars
5039: ?boxerrorbars
5040: The `boxerrorbars` style is only relevant to 2-d data plotting. It is a
5041: combination of the `boxes` and `yerrorbars` styles. The boxwidth will come
5042: from the fourth column if the y errors are in the form of "ydelta" and the
5043: boxwidth was not previously set equal to -2.0 (`set boxwidth -2.0`) or from
5044: the fifth column if the y errors are in the form of "ylow yhigh". The
5045: special case `boxwidth = -2.0` is for four-column data with y errors in the
5046: form "ylow yhigh". In this case the boxwidth will be calculated so that each
5047: box touches the adjacent boxes. The width will also be calculated in cases
5048: where three-column data are used.
5049:
5050: The box height is determined from the y error in the same way as it is for
5051: the `yerrorbars` style---either from y-ydelta to y+ydelta or from ylow to
5052: yhigh, depending on how many data columns are provided.
5053: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html"> See Demo. </a>
5054: 4 boxes
5055: ?commands set style boxes
5056: ?commands set style bargraph
5057: ?set style boxes
5058: ?set style bargraph
5059: ?style boxes
5060: ?style bargraph
5061: ?boxes
5062: ?bargraph
5063: The `boxes` style is only relevant to 2-d plotting. It draws a box centered
5064: about the given x coordinate from the x axis (not the graph border) to the
5065: given y coordinate. The width of the box is obtained in one of three ways.
5066: If it is a data plot and the data file has a third column, this will be used
5067: to set the width of the box. If not, if a width has been set using the `set
5068: boxwidth` command, this will be used. If neither of these is available, the
5069: width of each box will be calculated automatically so that it touches the
5070: adjacent boxes.
5071: 4 boxxyerrorbars
5072: ?commands set style boxxyerrorbars
5073: ?set style boxxyerrorbars
5074: ?style boxxyerrorbars
5075: ?boxxyerrorbars
5076: The `boxxyerrorbars` style is only relevant to 2-d data plotting. It is a
5077: combination of the `boxes` and `xyerrorbars` styles.
5078:
5079: The box width and height are determined from the x and y errors in the same
5080: way as they are for the `xyerrorbars` style---either from xlow to xhigh and
5081: from ylow to yhigh, or from x-xdelta to x+xdelta and from y-ydelta to
5082: y+ydelta , depending on how many data columns are provided.
5083: 4 candlesticks
5084: ?commands set style candlesticks
5085: ?set style candlesticks
5086: ?style candlesticks
5087: ?candlesticks
5088: The `candlesticks` style is only relevant for 2-d data plotting of financial
5089: data. Five columns of data are required; in order, these should be the x
5090: coordinate (most likely a date) and the opening, low, high, and closing
5091: prices. The symbol is an open rectangle, centered horizontally at the x
5092: coordinate and limited vertically by the opening and closing prices. A
5093: vertical line segment at the x coordinate extends up from the top of the
5094: rectangle to the high price and another down to the low. The width of the
5095: rectangle may be changed by `set bar`. The symbol will be unchanged if the
5096: low and high prices are interchanged or if the opening and closing prices
5097: are interchanged. See `set bar` and `financebars`.
5098: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/finance/finance.html"> See demos.</a>
5099: 4 dots
5100: ?commands set style dots
5101: ?set style dots
5102: ?style dots
5103: ?dots
5104: The `dots` style plots a tiny dot at each point; this is useful for scatter
5105: plots with many points.
5106: 4 financebars
5107: ?commands set style financebars
5108: ?set style financebars
5109: ?style financebars
5110: ?financebars
5111: The `financebars` style is only relevant for 2-d data plotting of financial
5112: data. Five columns of data are required; in order, these should be the x
5113: coordinate (most likely a date) and the opening, low, high, and closing
5114: prices. The symbol is a vertical line segment, located horizontally at the x
5115: coordinate and limited vertically by the high and low prices. A horizontal
5116: tic on the left marks the opening price and one on the right marks the
5117: closing price. The length of these tics may be changed by `set bar`. The
5118: symbol will be unchanged if the high and low prices are interchanged. See
5119: `set bar` and `candlesticks`.
5120: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/finance/finance.html"> See demos.</a>
5121: 4 fsteps
5122: ?commands set style fsteps
5123: ?set style fsteps
5124: ?style fsteps
5125: ?fsteps
5126: The `fsteps` style is only relevant to 2-d plotting. It connects consecutive
5127: points with two line segments: the first from (x1,y1) to (x1,y2) and the
5128: second from (x1,y2) to (x2,y2).
5129: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/steps/steps.html"> See demo. </a>
5130: 4 histeps
5131: ?commands set style histeps
5132: ?set style histeps
5133: ?style histeps
5134: ?histeps
5135: The `histeps` style is only relevant to 2-d plotting. It is intended for
5136: plotting histograms. Y-values are assumed to be centered at the x-values;
5137: the point at x1 is represented as a horizontal line from ((x0+x1)/2,y1) to
5138: ((x1+x2)/2,y1). The lines representing the end points are extended so that
5139: the step is centered on at x. Adjacent points are connected by a vertical
5140: line at their average x, that is, from ((x1+x2)/2,y1) to ((x1+x2)/2,y2).
5141:
5142: If `autoscale` is in effect, it selects the xrange from the data rather than
5143: the steps, so the end points will appear only half as wide as the others.
5144: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/steps/steps.html"> See demo. </a>
5145:
5146: `histeps` is only a plotting style; `gnuplot` does not have the ability to
5147: create bins and determine their population from some data set.
5148: 4 impulses
5149: ?commands set style impulses
5150: ?set style impulses
5151: ?style impulses
5152: ?impulses
5153: The `impulses` style displays a vertical line from the x axis (not the graph
5154: border), or from the grid base for `splot`, to each point.
5155: 4 lines
5156: ?commands set style lines
5157: ?set style lines
5158: ?style lines
5159: ?lines
5160: The `lines` style connects adjacent points with straight line segments.
5161: 4 linespoints
5162: ?commands set style linespoints
5163: ?commands set style lp
5164: ?set style linespoints
5165: ?set style lp
5166: ?style linespoints
5167: ?style lp
5168: ?linespoints
5169: ?lp
5170: The `linespoints` style does both `lines` and `points`, that is, it draws a
5171: small symbol at each point and then connects adjacent points with straight
5172: line segments. The command `set pointsize` may be used to change the size of
5173: the points. See `set pointsize` for its usage.
5174:
5175: `linespoints` may be abbreviated `lp`.
5176: 4 points
5177: ?commands set style points
5178: ?set style points
5179: ?style points
5180: ?points
5181: The `points` style displays a small symbol at each point. The command `set
5182: pointsize` may be used to change the size of the points. See `set pointsize`
5183: for its usage.
5184: 4 steps
5185: ?commands set style steps
5186: ?set style steps
5187: ?style steps
5188: ?steps
5189: The `steps` style is only relevant to 2-d plotting. It connects consecutive
5190: points with two line segments: the first from (x1,y1) to (x2,y1) and the
5191: second from (x2,y1) to (x2,y2).
5192: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/steps/steps.html"> See demo. </a>
5193: 4 vector
5194: ?commands set style vector
5195: ?set style vector
5196: ?style vector
5197: ?vector
5198: The `vector` style draws a vector from (x,y) to (x+xdelta,y+ydelta). Thus
5199: it requires four columns of data. It also draws a small arrowhead at the
5200: end of the vector.
5201:
5202: The `vector` style is still experimental: it doesn't get clipped properly
5203: and other things may also be wrong with it. Use it at your own risk.
5204: 4 xerrorbars
5205: ?commands set style xerrorbars
5206: ?set style xerrorbars
5207: ?style xerrorbars
5208: ?xerrorbars
5209: The `xerrorbars` style is only relevant to 2-d data plots. `xerrorbars` is
5210: like `dots`, except that a horizontal error bar is also drawn. At each point
5211: (x,y), a line is drawn from (xlow,y) to (xhigh,y) or from (x-xdelta,y) to
5212: (x+xdelta,y), depending on how many data columns are provided. A tic mark
5213: is placed at the ends of the error bar (unless `set bar` is used---see `set
5214: bar` for details).
5215: 4 xyerrorbars
5216: ?commands set style xyerrorbars
5217: ?set style xyerrorbars
5218: ?style xyerrorbars
5219: ?xyerrorbars
5220: The `xyerrorbars` style is only relevant to 2-d data plots. `xyerrorbars` is
5221: like `dots`, except that horizontal and vertical error bars are also drawn.
5222: At each point (x,y), lines are drawn from (x,y-ydelta) to (x,y+ydelta) and
5223: from (x-xdelta,y) to (x+xdelta,y) or from (x,ylow) to (x,yhigh) and from
5224: (xlow,y) to (xhigh,y), depending upon the number of data columns provided. A
5225: tic mark is placed at the ends of the error bar (unless `set bar` is
5226: used---see `set bar` for details).
5227:
5228: If data are provided in an unsupported mixed form, the `using` filter on the
5229: `plot` command should be used to set up the appropriate form. For example,
5230: if the data are of the form (x,y,xdelta,ylow,yhigh), then you can use
5231:
5232: plot 'data' using 1:2:($1-$3),($1+$3),4,5 with xyerrorbars
5233: 4 yerrorbars
5234: ?commands set style yerrorbars
5235: ?commands set style errorbars
5236: ?set style yerrorbars
5237: ?set style errorbars
5238: ?style yerrorbars
5239: ?style errorbars
5240: ?yerrorbars
5241: ?errorbars
5242: The `yerrorbars` (or `errorbars`) style is only relevant to 2-d data plots.
5243: `yerrorbars` is like `dots`, except that a vertical error bar is also drawn.
5244: At each point (x,y), a line is drawn from (x,y-ydelta) to (x,y+ydelta) or
5245: from (x,ylow) to (x,yhigh), depending on how many data columns are provided.
5246: A tic mark is placed at the ends of the error bar (unless `set bar` is
5247: used---see `set bar` for details).
5248: ^<a href="http://www.nas.nasa.gov/~woo/gnuplot/errorbar/errorbar.html"> See demo. </a>
5249: 3 surface
5250: ?commands set surface
5251: ?commands set nosurface
5252: ?commands show surface
5253: ?set surface
5254: ?set nosurface
5255: ?show surface
5256: ?surface
5257: ?nosurface
5258: The command `set surface` controls the display of surfaces by `splot`.
5259:
5260: Syntax:
5261: set surface
5262: set nosurface
5263: show surface
5264:
5265: The surface is drawn with the style specifed by `with`, or else the
5266: appropriate style, data or function.
5267:
5268: Whenever `set nosurface` is issued, `splot` will not draw points or lines
5269: corresponding to the function or data file points. Contours may be still be
5270: drawn on the surface, depending on the `set contour` option. `set nosurface;
5271: set contour base` is useful for displaying contours on the grid base. See
5272: also `set contour`.
5273: ^ <h2> Terminal Types </h2>
5274: 3 terminal
5275: ?commands set terminal
5276: ?commands show terminal
5277: ?set terminal
5278: ?set term
5279: ?show terminal
5280: ?terminal
5281: ?term
5282: `gnuplot` supports many different graphics devices. Use `set terminal` to
5283: tell `gnuplot` what kind of output to generate. Use `set output` to redirect
5284: that output to a file or device.
5285:
5286: Syntax:
5287: set terminal {<terminal-type>}
5288: show terminal
5289:
5290: If <terminal-type> is omitted, `gnuplot` will list the available terminal
5291: types. <terminal-type> may be abbreviated.
5292:
5293: If both `set terminal` and `set output` are used together, it is safest to
5294: give `set terminal` first, because some terminals set a flag which is needed
5295: in some operating systems.
5296:
5297: Several terminals have additional options. For example, see `dumb`,
5298: `iris4d`, `hpljii` or `postscript`.
5299:
5300: This document may describe drivers that are not available to you because they
5301: were not installed, or it may not describe all the drivers that are available
5302: to you, depending on its output format.
5303: <4 -- all terminal stuff is pulled from the .trm files
5304: 3 tics
5305: ?commands set tics
5306: ?commands show tics
5307: ?set tics
5308: ?show tics
5309: ?tics
5310: The `set tics` command can be used to change the tics to be drawn outwards.
5311:
5312: Syntax:
5313: set tics {<direction>}
5314: show tics
5315:
5316: where <direction> may be `in` (the default) or `out`.
5317:
5318: See also `set xtics` for more control of major (labelled) tic marks and `set
5319: mxtics` for control of minor tic marks.
5320: 3 ticslevel
5321: ?commands set ticslevel
5322: ?commands show ticslevel
5323: ?set ticslevel
5324: ?show ticslevel
5325: ?ticslevel
5326: Using `splot`, one can adjust the relative height of the vertical (Z) axis
5327: using `set ticslevel`. The numeric argument provided specifies the location
5328: of the bottom of the scale (as a fraction of the z-range) above the xy-plane.
5329: The default value is 0.5. Negative values are permitted, but tic labels on
5330: the three axes may overlap.
5331:
5332: To place the xy-plane at a position 'pos' on the z-axis, `ticslevel` should
5333: be set equal to (pos - zmin) / (zmin - zmax).
5334:
5335: Syntax:
5336: set ticslevel {<level>}
5337: show tics
5338:
5339: See also `set view`.
5340: 3 ticscale
5341: ?commands set ticscale
5342: ?commands show ticscale
5343: ?set ticscale
5344: ?show ticscale
5345: ?ticscale
5346: The size of the tic marks can be adjusted with `set ticscale`.
5347:
5348: Syntax:
5349: set ticscale {<major> {<minor>}}
5350: show tics
5351:
5352: If <minor> is not specified, it is 0.5*<major>. The default size is 1.0 for
5353: major tics and 0.5 for minor tics. Note that it is possible to have the tic
5354: marks pointing outward by specifying a negative size.
5355: 3 timestamp
5356: ?commands set timestamp
5357: ?commands set time
5358: ?commands set notimestamp
5359: ?commands show timestamp
5360: ?set timestamp
5361: ?set time
5362: ?set notimestamp
5363: ?show timestamp
5364: ?timestamp
5365: ?notimestamp
5366: The command `set timestamp` places the time and date of the plot in the left
5367: margin.
5368:
5369: Syntax:
5370: set timestamp {"<format>"} {top|bottom} {{no}rotate}
5371: {<xoff>}{,<yoff>} {"<font>"}
5372: set notimestamp
5373: show timestamp
5374:
5375: The format string allows you to choose the format used to write the date and
5376: time. Its default value is what asctime() uses: "%a %b %d %H:%M:%S %Y"
5377: (weekday, month name, day of the month, hours, minutes, seconds, four-digit
5378: year). With `top` or `bottom` you can place the timestamp at the top or
5379: bottom of the left margin (default: bottom). `rotate` lets you write the
5380: timestamp vertically, if your terminal supports vertical text. The constants
5381: <xoff> and <off> are offsets from the default position given in character
5382: screen coordinates. <font> is used to specify the font with which the time
5383: is to be written.
5384:
5385: The abbreviation `time` may be used in place of `timestamp`.
5386:
5387: Example:
5388: set timestamp "%d/%m/%y %H:%M" 80,-2 "Helvetica"
5389:
5390: See `set timefmt` for more information about time format strings.
5391: 3 timefmt
5392: ?commands set timefmt
5393: ?commands show timefmt
5394: ?set timefmt
5395: ?show timefmt
5396: ?timefmt
5397: This command applies to timeseries where data are composed of dates/times.
5398: It has no meaning unless the command `set xdata time` is given also.
5399:
5400: Syntax:
5401: set timefmt "<format string>"
5402: show timefmt
5403:
5404: The string argument tells `gnuplot` how to read timedata from the datafile.
5405: The valid formats are:
5406:
5407: @start table - first is interactive cleartext form
5408: Format Explanation
5409: %d day of the month, 1--31
5410: %m month of the year, 1--12
5411: %y year, 0--99
5412: %Y year, 4-digit
5413: %j day of the year, 1--365
5414: %H hour, 0--24
5415: %M minute, 0--60
5416: %S second, 0--60
5417: %b three-character abbreviation of the name of the month
5418: %B name of the month
5419: #\begin{tabular}{|cl|} \hline
5420: #\multicolumn{2}{|c|}{Time Series timedata Format Specifiers}\\
5421: #\hline \hline
5422: #Format & Explanation \\ \hline
5423: #\verb@%d@ & day of the month, 1--31 \\
5424: #\verb@%m@ & month of the year, 1--12 \\
5425: #\verb@%y@ & year, 0--99 \\
5426: #\verb@%Y@ & year, 4-digit \\
5427: #\verb@%j@ & day of the year, 1--365 \\
5428: #\verb@%H@ & hour, 0--24 \\
5429: #\verb@%M@ & minute, 0--60 \\
5430: #\verb@%S@ & second, 0--60 \\
5431: #\verb@%b@ & three-character abbreviation of the name of the month \\
5432: #\verb@%B@ & name of the month \\
5433: %c l .
5434: %Format@Explanation
5435: %_
5436: %%d@day of the month, 1--31
5437: %%m@month of the year, 1--12
5438: %%y@year, 0--99
5439: %%Y@year, 4-digit
5440: %%j@day of the year, 1--365
5441: %%H@hour, 0--24
5442: %%M@minute, 0--60
5443: %%S@second, 0--60
5444: %%b@three-character abbreviation of the name of the month
5445: %%B@name of the month
5446: %_
5447: @end table
5448: Any character is allowed in the string, but must match exactly. \t (tab) is
5449: recognized. Backslash-octals (\nnn) are converted to char. If there is no
5450: separating character between the time/date elements, then %d, %m, %y, %H, %M
5451: and %S read two digits each, %Y reads four digits and %j reads three digits.
5452: %b requires three characters, and %B requires as many as it needs.
5453:
5454: Spaces are treated slightly differently. A space in the string stands for
5455: zero or more whitespace characters in the file. That is, "%H %M" can be used
5456: to read "1220" and "12 20" as well as "12 20".
5457:
5458: Each set of non-blank characters in the timedata counts as one column in the
5459: `using n:n` specification. Thus `11:11 25/12/76 21.0` consists of three
5460: columns. To avoid confusion, `gnuplot` requires that you provide a complete
5461: `using` specification if your file contains timedata.
5462:
5463: Since `gnuplot` cannot read non-numerical text, if the date format includes
5464: the day or month in words, the format string must exclude this text. But
5465: it can still be printed with the "%a", "%A", "%b", or "%B" specifier: see
5466: `set format` for more details about these and other options for printing
5467: timedata. (`gnuplot` will determine the proper month and weekday from the
5468: numerical values.)
5469:
5470: See also `set xdata` and `Time/date` for more information.
5471:
5472: Example:
5473: set timefmt "%d/%m/%Y\t%H:%M"
5474: tells `gnuplot` to read date and time separated by tab. (But look closely at
5475: your data---what began as a tab may have been converted to spaces somewhere
5476: along the line; the format string must match what is actually in the file.)
5477: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/timedat/timedat.html"> Time Data Demo </a>
5478: 3 title
5479: ?commands set title
5480: ?commands show title
5481: ?set title
5482: ?show title
5483: ?title
5484: The `set title` command produces a plot title that is centered at the top of
5485: the plot. `set title` is a special case of `set label`.
5486:
5487: Syntax:
5488: set title {"<title-text>"} {<xoff>}{,<yoff>} {"<font>,{<size>}"}
5489: show title
5490:
5491: Specifying constants <xoff> or <yoff> as optional offsets for the title will
5492: move the title <xoff> or <yoff> character screen coordinates (not graph
5493: coordinates). For example, "`set title ,-1`" will change only the y offset
5494: of the title, moving the title down by roughly the height of one character.
5495:
5496: <font> is used to specify the font with which the title is to be written;
5497: the units of the font <size> depend upon which terminal is used.
5498:
5499: `set title` with no parameters clears the title.
5500:
5501: See `syntax` for details about the processing of backslash sequences and
5502: the distinction between single- and double-quotes.
5503: 3 tmargin
5504: ?commands set tmargin
5505: ?set tmargin
5506: ?tmargin
5507: The command `set tmargin` sets the size of the top margin. Please see
5508: `set margin` for details.
5509: 3 trange
5510: ?commands set trange
5511: ?commands show trange
5512: ?set trange
5513: ?show trange
5514: ?trange
5515: The `set trange` command sets the parametric range used to compute x and y
5516: values when in parametric or polar modes. Please see `set xrange` for
5517: details.
5518: 3 urange
5519: ?commands set urange
5520: ?commands show urange
5521: ?set urange
5522: ?show urange
5523: ?urange
5524: The `set urange` and `set vrange` commands set the parametric ranges used
5525: to compute x, y, and z values when in `splot` parametric mode. Please see
5526: `set xrange` for details.
5527: 3 variables
5528: ?commands show variables
5529: ?show variables
5530: The `show variables` command lists all user-defined variables and their
5531: values.
5532:
5533: Syntax:
5534: show variables
5535: 3 version
5536: ?show version
5537: The `show version` command lists the version of gnuplot being run, its last
5538: modification date, the copyright holders, and email addresses for the FAQ,
5539: the info-gnuplot mailing list, and reporting bugs--in short, the information
5540: listed on the screen when the program is invoked interactively.
5541:
5542: Syntax:
5543: show version {long}
5544:
5545: When the `long` option is given, it also lists the operating system, the
5546: compilation options used when `gnuplot` was installed, the location of the
5547: help file, and (again) the useful email addresses.
5548: 3 view
5549: ?commands set view
5550: ?commands show view
5551: ?set view
5552: ?show view
5553: ?view
5554: The `set view` command sets the viewing angle for `splot`s. It controls how
5555: the 3-d coordinates of the plot are mapped into the 2-d screen space. It
5556: provides controls for both rotation and scaling of the plotted data, but
5557: supports orthographic projections only.
5558:
5559: Syntax:
5560: set view <rot_x> {,{<rot_z>}{,{<scale>}{,<scale_z>}}}
5561: show view
5562:
5563: where <rot_x> and <rot_z> control the rotation angles (in degrees) in a
5564: virtual 3-d coordinate system aligned with the screen such that initially
5565: (that is, before the rotations are performed) the screen horizontal axis is
5566: x, screen vertical axis is y, and the axis perpendicular to the screen is z.
5567: The first rotation applied is <rot_x> around the x axis. The second rotation
5568: applied is <rot_z> around the new z axis.
5569:
5570: <rot_x> is bounded to the [0:180] range with a default of 60 degrees, while
5571: <rot_z> is bounded to the [0:360] range with a default of 30 degrees.
5572: <scale> controls the scaling of the entire `splot`, while <scale_z> scales
5573: the z axis only. Both scales default to 1.0.
5574:
5575: Examples:
5576: set view 60, 30, 1, 1
5577: set view ,,0.5
5578:
5579: The first sets all the four default values. The second changes only scale,
5580: to 0.5.
5581:
5582: See also `set ticslevel`.
5583: 3 vrange
5584: ?commands set vrange
5585: ?commands show vrange
5586: ?set vrange
5587: ?show vrange
5588: ?vrange
5589: The `set urange` and `set vrange` commands set the parametric ranges used
5590: to compute x, y, and z values when in `splot` parametric mode. Please see
5591: `set xrange` for details.
5592: 3 x2data
5593: ?commands set x2data
5594: ?commands show x2data
5595: ?set x2data
5596: ?show x2data
5597: ?x2data
5598: The `set x2data` command sets data on the x2 (top) axis to timeseries
5599: (dates/times). Please see `set xdata`.
5600: 3 x2dtics
5601: ?commands set x2dtics
5602: ?commands set nox2dtics
5603: ?commands show x2dtics
5604: ?set x2dtics
5605: ?set nox2dtics
5606: ?show x2dtics
5607: ?x2dtics
5608: ?nox2dtics
5609: The `set x2dtics` command changes tics on the x2 (top) axis to days of the
5610: week. Please see `set xdtics` for details.
5611: 3 x2label
5612: ?commands set x2label
5613: ?commands show x2label
5614: ?set x2label
5615: ?show x2label
5616: ?x2label
5617: The `set x2label` command sets the label for the x2 (top) axis. Please see
5618: `set xlabel`.
5619: 3 x2mtics
5620: ?commands set x2mtics
5621: ?commands set nox2mtics
5622: ?commands show x2mtics
5623: ?set x2mtics
5624: ?set nox2mtics
5625: ?show x2mtics
5626: ?x2mtics
5627: ?nox2mtics
5628: The `set x2mtics` command changes tics on the x2 (top) axis to months of the
5629: year. Please see `set xmtics` for details.
5630: 3 x2range
5631: ?commands set x2range
5632: ?commands show x2range
5633: ?set x2range
5634: ?show x2range
5635: ?x2range
5636: The `set x2range` command sets the horizontal range that will be displayed on
5637: the x2 (top) axis. Please see `set xrange` for details.
5638: 3 x2tics
5639: ?commands set x2tics
5640: ?commands set nox2tics
5641: ?commands show x2tics
5642: ?set x2tics
5643: ?set nox2tics
5644: ?show x2tics
5645: ?x2tics
5646: ?nox2tics
5647: The `set x2tics` command controls major (labelled) tics on the x2 (top) axis.
5648: Please see `set xtics` for details.
5649: 3 x2zeroaxis
5650: ?commands set x2zeroaxis
5651: ?commands set nox2zeroaxis
5652: ?commands show x2zeroaxis
5653: ?set x2zeroaxis
5654: ?set nox2zeroaxis
5655: ?show x2zeroaxis
5656: ?x2zeroaxis
5657: ?nox2zeroaxis
5658: The `set x2zeroaxis` command draws a line at the origin of the x2 (top) axis
5659: (y2 = 0). For details, please see
5660: `set zeroaxis`.
5661: 3 xdata
5662: ?commands set xdata
5663: ?commands show xdata
5664: ?set xdata
5665: ?show xdata
5666: ?xdata
5667: This command sets the datatype on the x axis to time/date. A similar command
5668: does the same thing for each of the other axes.
5669:
5670: Syntax:
5671: set xdata {time}
5672: show xdata
5673:
5674: The same syntax applies to `ydata`, `zdata`, `x2data` and `y2data`.
5675:
5676: The `time` option signals that the datatype is indeed time/date. If the
5677: option is not specified, the datatype reverts to normal.
5678:
5679: See `set timefmt` to tell `gnuplot` how to read date or time data. The
5680: time/date is converted to seconds from start of the century. There is
5681: currently only one timefmt, which implies that all the time/date columns must
5682: confirm to this format. Specification of ranges should be supplied as quoted
5683: strings according to this format to avoid interpretation of the time/date as
5684: an expression.
5685:
5686: The function 'strftime' (type "man strftime" on unix to look it up) is used
5687: to print tic-mark labels. `gnuplot` tries to figure out a reasonable format
5688: for this unless the `set format x "string"` has supplied something that does
5689: not look like a decimal format (more than one '%' or neither %f nor %g).
5690:
5691: See also `Time/date` for more information.
5692: 3 xdtics
5693: ?commands set xdtics
5694: ?commands set noxdtics
5695: ?commands show xdtics
5696: ?set xdtics
5697: ?set noxdtics
5698: ?show xdtics
5699: ?xdtics
5700: ?noxdtics
5701: The `set xdtics` commands converts the x-axis tic marks to days of the week
5702: where 0=Sun and 6=Sat. Overflows are converted modulo 7 to dates. `set
5703: noxdtics` returns the labels to their default values. Similar commands do
5704: the same things for the other axes.
5705:
5706: Syntax:
5707: set xdtics
5708: set noxdtics
5709: show xdtics
5710:
5711: The same syntax applies to `ydtics`, `zdtics`, `x2dtics` and `y2dtics`.
5712:
5713: See also the `set format` command.
5714: 3 xlabel
5715: ?commands set xlabel
5716: ?commands show xlabel
5717: ?set xlabel
5718: ?show xlabel
5719: ?xlabel
5720: The `set xlabel` command sets the x axis label. Similar commands set labels
5721: on the other axes.
5722:
5723: Syntax:
5724: set xlabel {"<label>"} {<xoff>}{,<yoff>} {"<font>{,<size>}"}
5725: show xlabel
5726:
5727: The same syntax applies to `x2label`, `ylabel`, `y2label` and `zlabel`.
5728:
5729: Specifying the constants <xoff> or <yoff> as optional offsets for a label
5730: will move it <xoff> or <yoff> character widths or heights. For example,
5731: "` set xlabel -1`" will change only the x offset of the xlabel, moving the
5732: label roughly one character width to the left. The size of a character
5733: depends on both the font and the terminal.
5734:
5735: <font> is used to specify the font in which the label is written; the units
5736: of the font <size> depend upon which terminal is used.
5737:
5738: To clear a label, put no options on the command line, e.g., "`set y2label`".
5739:
5740: The default positions of the axis labels are as follows:
5741:
5742: xlabel: The x-axis label is centered below the bottom axis.
5743:
5744: ylabel: The position of the y-axis label depends on the terminal, and can be
5745: one of the following three positions:
5746:
5747: 1. Horizontal text flushed left at the top left of the plot. Terminals that
5748: cannot rotate text will probably use this method. If `set x2tics` is also
5749: in use, the ylabel may overwrite the left-most x2tic label. This may be
5750: remedied by adjusting the ylabel position or the left margin.
5751:
5752: 2. Vertical text centered vertically at the left of the plot. Terminals
5753: that can rotate text will probably use this method.
5754:
5755: 3. Horizontal text centered vertically at the left of the plot. The EEPIC,
5756: LaTeX and TPIC drivers use this method. The user must insert line breaks
5757: using \\ to prevent the ylabel from overwriting the plot. To produce a
5758: vertical row of characters, add \\ between every printing character (but this
5759: is ugly).
5760:
5761: zlabel: The z-axis label is centered along the z axis and placed in the space
5762: above the grid level.
5763:
5764: y2label: The y2-axis label is placed to the right of the y2 axis. The
5765: position is terminal-dependent in the same manner as is the y-axis label.
5766:
5767: x2label: The x2-axis label is placed above the top axis but below the plot
5768: title. It is also possible to create an x2-axis label by using new-line
5769: characters to make a multi-line plot title, e.g.,
5770:
5771: set title "This is the title\n\nThis is the x2label"
5772:
5773: Note that double quotes must be used. The same font will be used for both
5774: lines, of course.
5775:
5776: If you are not satisfied with the default position of an axis label, use `set
5777: label` instead--that command gives you much more control over where text is
5778: placed.
5779:
5780: Please see `set syntax` for further information about backslash processing
5781: and the difference between single- and double-quoted strings.
5782: 3 xmtics
5783: ?commands set xmtics
5784: ?commands set noxmtics
5785: ?commands show xmtics
5786: ?set xmtics
5787: ?set noxmtics
5788: ?show xmtics
5789: ?xmtics
5790: ?noxmtics
5791: The `set xmtics` commands converts the x-axis tic marks to months of the
5792: year where 1=Jan and 12=Dec. Overflows are converted modulo 12 to months.
5793: The tics are returned to their default labels by `set noxmtics`. Similar
5794: commands perform the same duties for the other axes.
5795:
5796: Syntax:
5797: set xmtics
5798: set noxmtics
5799: show xmtics
5800:
5801: The same syntax applies to `x2mtics`, `ymtics`, `y2mtics`, and `zmtics`.
5802:
5803: See also the `set format` command.
5804: 3 xrange
5805: ?commands set xrange
5806: ?commands show xrange
5807: ?set xrange
5808: ?show xrange
5809: ?xrange
5810: The `set xrange` command sets the horizontal range that will be displayed.
5811: A similar command exists for each of the other axes, as well as for the
5812: polar radius r and the parametric variables t, u, and v.
5813:
5814: Syntax:
5815: set xrange [{{<min>}:{<max>}}] {{no}reverse} {{no}writeback}
5816: show xrange
5817:
5818: where <min> and <max> terms are constants, expressions or an asterisk to set
5819: autoscaling. If the data are time/date, you must give the range as a quoted
5820: string according to the `set timefmt` format. Any value omitted will not be
5821: changed.
5822:
5823: The same syntax applies to `yrange`, `zrange`, `x2range`, `y2range`,
5824: `rrange`, `trange`, `urange` and `vrange`.
5825:
5826: The `reverse` option reverses the direction of the axis, e.g., `set xrange
5827: [0:1] reverse` will produce an axis with 1 on the left and 0 on the right.
5828: This is identical to the axis produced by `set xrange [1:0]`, of course.
5829: `reverse` is intended primarily for use with `autoscale`.
5830:
5831: The `writeback` option essentially saves the range found by `autoscale` in
5832: the buffers that would be filled by `set xrange`. This is useful if you wish
5833: to plot several functions together but have the range determined by only
5834: some of them. The `writeback` operation is performed during the `plot`
5835: execution, so it must be specified before that command. For example,
5836:
5837: set xrange [-10:10]
5838: set yrange [] writeback
5839: plot sin(x)
5840: set noautoscale y
5841: replot x/2
5842:
5843: results in a yrange of [-1:1] as found only from the range of sin(x); the
5844: [-5:5] range of x/2 is ignored. Executing `show yrange` after each command
5845: in the above example should help you understand what is going on.
5846:
5847: In 2-d, `xrange` and `yrange` determine the extent of the axes, `trange`
5848: determines the range of the parametric variable in parametric mode or the
5849: range of the angle in polar mode. Similarly in parametric 3-d, `xrange`,
5850: `yrange`, and `zrange` govern the axes and `urange` and `vrange` govern the
5851: parametric variables.
5852:
5853: In polar mode, `rrange` determines the radial range plotted. <rmin> acts as
5854: an additive constant to the radius, whereas <rmax> acts as a clip to the
5855: radius---no point with radius greater than <rmax> will be plotted. `xrange`
5856: and `yrange` are affected---the ranges can be set as if the graph was of
5857: r(t)-rmin, with rmin added to all the labels.
5858:
5859: Any range may be partially or totally autoscaled, although it may not make
5860: sense to autoscale a parametric variable unless it is plotted with data.
5861:
5862: Ranges may also be specified on the `plot` command line. A range given on
5863: the plot line will be used for that single `plot` command; a range given by
5864: a `set` command will be used for all subsequent plots that do not specify
5865: their own ranges. The same holds true for `splot`.
5866:
5867: Examples:
5868:
5869: To set the xrange to the default:
5870: set xrange [-10:10]
5871:
5872: To set the yrange to increase downwards:
5873: set yrange [10:-10]
5874:
5875: To change zmax to 10 without affecting zmin (which may still be autoscaled):
5876: set zrange [:10]
5877:
5878: To autoscale xmin while leaving xmax unchanged:
5879: set xrange [*:]
5880: 3 xtics
5881: ?commands set xtics
5882: ?commands set noxtics
5883: ?commands show xtics
5884: ?set xtics
5885: ?set noxtics
5886: ?show xtics
5887: ?xtics
5888: ?noxtics
5889: Fine control of the major (labelled) tics on the x axis is possible with the
5890: `set xtics` command. The tics may be turned off with the `set noxtics`
5891: command, and may be turned on (the default state) with `set xtics`. Similar
5892: commands control the major tics on the y, z, x2 and y2 axes.
5893:
5894: Syntax:
5895: set xtics {axis | border} {{no}mirror} {{no}rotate}
5896: { autofreq
5897: | <incr>
5898: | <start>, <incr> {,<end>}
5899: | ({"<label>"} <pos> {,{"<label>"} <pos>}...) }
5900: set noxtics
5901: show xtics
5902:
5903: The same syntax applies to `ytics`, `ztics`, `x2tics` and `y2tics`.
5904:
5905: `axis` or `border` tells `gnuplot` to put the tics (both the tics themselves
5906: and the accompanying labels) along the axis or the border, respectively.
5907: `mirror` tells it to put unlabelled tics at the same positions on the
5908: opposite border. `nomirror` does what you think it does. `rotate` asks
5909: `gnuplot` to rotate the text through 90 degrees, if the underlying terminal
5910: driver supports text rotation. `norotate` cancels this. The defaults are
5911: `border mirror norotate` for tics on the x and y axes, and `border nomirror
5912: norotate` for tics on the x2 and y2 axes. For the z axis, the the `{axis |
5913: border}` option is not available and the default is `nomirror`. If you do
5914: want to mirror the z-axis tics, you might want to create a bit more room for
5915: them with `set border`.
5916:
5917: `set xtics` with no options restores the default border if xtics are not
5918: being displayed; otherwise it has no effect. Any previously specified
5919: tic frequency or position {and labels} are retained.
5920:
5921: Positions of the tics are calculated automatically by default or if the
5922: `autofreq` option is given; otherwise they may be specified in either of
5923: two forms:
5924:
5925: The implicit <start>, <incr>, <end> form specifies that a series of tics will
5926: be plotted on the axis between the values <start> and <end> with an increment
5927: of <incr>. If <end> is not given, it is assumed to be infinity. The
5928: increment may be negative. If neither <start> nor <end> is given, <start> is
5929: assumed to be negative infinity, <end> is assumed to be positive infinity,
5930: and the tics will be drawn at integral multiples of <step>. If the axis is
5931: logarithmic, the increment will be used as a multiplicative factor.
5932:
5933: Examples:
5934:
5935: Make tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.
5936: set xtics 0,.5,10
5937:
5938: Make tics at ..., -10, -5, 0, 5, 10, ...
5939: set xtics 5
5940:
5941: Make tics at 1, 100, 1e4, 1e6, 1e8.
5942: set logscale x; set xtics 1,100,10e8
5943:
5944: The explicit ("<label>" <pos>, ...) form allows arbitrary tic positions or
5945: non-numeric tic labels. A set of tics is a set of positions, each with its
5946: own optional label. Note that the label is a string enclosed by quotes. It
5947: may be a constant string, such as "hello", may contain formatting information
5948: for converting the position into its label, such as "%3f clients", or may be
5949: empty, "". See `set format` for more information. If no string is given,
5950: the default label (numerical) is used. In this form, the tics do not need to
5951: be listed in numerical order.
5952:
5953: Examples:
5954: set xtics ("low" 0, "medium" 50, "high" 100)
5955: set xtics (1,2,4,8,16,32,64,128,256,512,1024)
5956: set ytics ("bottom" 0, "" 10, "top" 20)
5957:
5958: In the second example, all tics are labelled. In the third, only the end
5959: tics are labelled.
5960:
5961: However they are specified, tics will only be plotted when in range.
5962:
5963: Format (or omission) of the tic labels is controlled by `set format`, unless
5964: the explicit text of a labels is included in the `set xtic (`<label>`)` form.
5965:
5966: Minor (unlabelled) tics can be added by the `set mxtics` command.
5967:
5968: In case of timeseries data, position values must be given as quoted dates
5969: or times according to the format `timefmt`. If the <start>, <incr>, <end>
5970: form is used, <start> and <end> must be given according to `timefmt`, but
5971: <incr> must be in seconds. Times will be written out according to the format
5972: given on `set format`, however.
5973:
5974: Examples:
5975: set xdata time
5976: set timefmt "%d/%m"
5977: set format x "%b %d"
5978: set xrange ["01/12":"06/12"]
5979: set xtics "01/12", 172800, "05/12"
5980:
5981: set xdata time
5982: set timefmt "%d/%m"
5983: set format x "%b %d"
5984: set xrange ["01/12":"06/12"]
5985: set xtics ("01/12", "" "03/12", "05/12")
5986: Both of these will produce tics "Dec 1", "Dec 3", and "Dec 5", but in the
5987: second example the tic at "Dec 3" will be unlabelled.
5988:
5989: 3 xzeroaxis
5990: ?commands set xzeroaxis
5991: ?commands set noxzeroaxis
5992: ?commands show xzeroaxis
5993: ?set xzeroaxis
5994: ?set noxzeroaxis
5995: ?show xzeroaxis
5996: ?xzeroaxis
5997: ?noxzeroaxis
5998: The `set xzeroaxis` command draws a line at y = 0. For details, please see
5999: `set zeroaxis`.
6000: 3 y2data
6001: ?commands set y2data
6002: ?commands show y2data
6003: ?set y2data
6004: ?show y2data
6005: ?y2data
6006: The `set y2data` command sets y2 (right-hand) axis data to timeseries
6007: (dates/times). Please see `set xdata`.
6008: 3 y2dtics
6009: ?commands set y2dtics
6010: ?commands set noy2dtics
6011: ?set y2dtics
6012: ?set noy2dtics
6013: ?show y2dtics
6014: ?y2dtics
6015: ?noy2dtics
6016: The `set y2dtics` command changes tics on the y2 (right-hand) axis to days of
6017: the week. Please see `set xdtics` for details.
6018: 3 y2label
6019: ?commands set y2label
6020: ?commands show y2label
6021: ?set y2label
6022: ?show y2label
6023: ?y2label
6024: The `set y2dtics` command sets the label for the y2 (right-hand) axis.
6025: Please see `set xlabel`.
6026: 3 y2mtics
6027: ?commands set y2mtics
6028: ?commands set noy2mtics
6029: ?commands show y2mtics
6030: ?set y2mtics
6031: ?set noy2mtics
6032: ?show y2mtics
6033: ?y2mtics
6034: ?noy2mtics
6035: The `set y2mtics` command changes tics on the y2 (right-hand) axis to months
6036: of the year. Please see `set xmtics` for details.
6037: 3 y2range
6038: ?commands set y2range
6039: ?commands show y2range
6040: ?set y2range
6041: ?show y2range
6042: ?y2range
6043: The `set y2range` command sets the vertical range that will be displayed on
6044: the y2 (right-hand) axis. Please see `set xrange` for details.
6045: 3 y2tics
6046: ?commands set y2tics
6047: ?commands set noy2tics
6048: ?commands show y2tics
6049: ?set y2tics
6050: ?set noy2tics
6051: ?show y2tics
6052: ?y2tics
6053: ?noy2tics
6054: The `set y2tics` command controls major (labelled) tics on the y2 (right-hand)
6055: axis. Please see `set xtics` for details.
6056: 3 y2zeroaxis
6057: ?commands set y2zeroaxis
6058: ?commands set noy2zeroaxis
6059: ?commands show y2zeroaxis
6060: ?set y2zeroaxis
6061: ?set noy2zeroaxis
6062: ?show y2zeroaxis
6063: ?y2zeroaxis
6064: ?noy2zeroaxis
6065: The `set y2zeroaxis` command draws a line at the origin of the y2 (right-hand)
6066: axis (x2 = 0). For details, please see `set zeroaxis`.
6067: 3 ydata
6068: ?commands set ydata
6069: ?commands show ydata
6070: ?set ydata
6071: ?show ydata
6072: ?ydata
6073: Sets y-axis data to timeseries (dates/times). Please see `set xdata`.
6074: 3 ydtics
6075: ?commands set ydtics
6076: ?commands set noydtics
6077: ?commands show ydtics
6078: ?set ydtics
6079: ?set noydtics
6080: ?show ydtics
6081: ?ydtics
6082: ?noydtics
6083: The `set ydtics` command changes tics on the y axis to days of the week.
6084: Please see `set xdtics` for details.
6085: 3 ylabel
6086: ?commands set ylabel
6087: ?commands show ylabel
6088: ?set ylabel
6089: ?show ylabel
6090: ?ylabel
6091: This command sets the label for the y axis. Please see `set xlabel`.
6092: 3 ymtics
6093: ?commands set ymtics
6094: ?commands set noymtics
6095: ?commands show ymtics
6096: ?set ymtics
6097: ?set noymtics
6098: ?show ymtics
6099: ?ymtics
6100: ?noymtics
6101: The `set ymtics` command changes tics on the y axis to months of the year.
6102: Please see `set xmtics` for details.
6103: 3 yrange
6104: ?commands set yrange
6105: ?commands show yrange
6106: ?set yrange
6107: ?show yrange
6108: ?yrange
6109: The `set yrange` command sets the vertical range that will be displayed on
6110: the y axis. Please see `set xrange` for details.
6111: 3 ytics
6112: ?commands set ytics
6113: ?commands set noytics
6114: ?commands show ytics
6115: ?set ytics
6116: ?set noytics
6117: ?show ytics
6118: ?ytics
6119: ?noytics
6120: The `set ytics` command controls major (labelled) tics on the y axis.
6121: Please see `set xtics` for details.
6122: 3 yzeroaxis
6123: ?commands set yzeroaxis
6124: ?commands set noyzeroaxis
6125: ?commands show yzeroaxis
6126: ?set yzeroaxis
6127: ?set noyzeroaxis
6128: ?show yzeroaxis
6129: ?yzeroaxis
6130: ?noyzeroaxis
6131: The `set yzeroaxis` command draws a line at x = 0. For details, please see
6132: `set zeroaxis`.
6133: 3 zdata
6134: ?commands set zdata
6135: ?commands show zdata
6136: ?set zdata
6137: ?show zdata
6138: ?zdata
6139: Set zaxis date to timeseries (dates/times). Please see `set xdata`.
6140: 3 zdtics
6141: ?commands set zdtics
6142: ?commands set nozdtics
6143: ?commands show zdtics
6144: ?set zdtics
6145: ?set nozdtics
6146: ?show zdtics
6147: ?zdtics
6148: ?nozdtics
6149: The `set zdtics` command changes tics on the z axis to days of the week.
6150: Please see `set xdtics` for details.
6151: 3 zero
6152: ?commands set zero
6153: ?commands show zero
6154: ?set zero
6155: ?show zero
6156: ?zero
6157: The `zero` value is the default threshold for values approaching 0.0.
6158:
6159: Syntax:
6160: set zero <expression>
6161: show zero
6162:
6163: `gnuplot` will not plot a point if its imaginary part is greater in magnitude
6164: than the `zero` threshold. This threshold is also used in various other
6165: parts of `gnuplot` as a (crude) numerical-error threshold. The default
6166: `zero` value is 1e-8. `zero` values larger than 1e-3 (the reciprocal of the
6167: number of pixels in a typical bitmap display) should probably be avoided, but
6168: it is not unreasonable to set `zero` to 0.0.
6169: 3 zeroaxis
6170: ?commands set zeroaxis
6171: ?commands set nozeroaxis
6172: ?commands show zeroaxis
6173: ?set zeroaxis
6174: ?set nozeroaxis
6175: ?show zeroaxis
6176: ?zeroaxis
6177: ?nozeroaxis
6178: The x axis may be drawn by `set xzeroaxis` and removed by `set noxzeroaxis`.
6179: Similar commands behave similarly for the y, x2, and y2 axes.
6180:
6181: Syntax:
6182: set {x|x2|y|y2|}zeroaxis { {linestyle | ls <line_style>}
6183: | { linetype | lt <line_type>}
6184: { linewidth | lw <line_width>}}
6185: set no{x|x2|y|y2|}zeroaxis
6186: show {x|y|}zeroaxis
6187:
6188:
6189: By default, these options are off. The selected zero axis is drawn
6190: with a line of type <line_type> and width <line_width> (if supported
6191: by the terminal driver currently in use), or a user-defined style
6192: <line_style>.
6193:
6194: If no linetype is specified, any zero axes selected will be drawn
6195: using the axis linetype (linetype 0).
6196:
6197: `set zeroaxis l` is equivalent to `set xzeroaxis l; set yzeroaxis l`. `set
6198: nozeroaxis` is equivalent to `set noxzeroaxis; set noyzeroaxis`.
6199: 3 zlabel
6200: ?commands set zlabel
6201: ?commands show zlabel
6202: ?set zlabel
6203: ?show zlabel
6204: ?zlabel
6205: This command sets the label for the z axis. Please see `set xlabel`.
6206: 3 zmtics
6207: ?commands set zmtics
6208: ?commands set nozmtics
6209: ?commands show zmtics
6210: ?set zmtics
6211: ?set nozmtics
6212: ?show zmtics
6213: ?zmtics
6214: ?nozmtics
6215: The `set zmtics` command changes tics on the z axis to months of the year.
6216: Please see `set xmtics` for details.
6217: 3 zrange
6218: ?commands set zrange
6219: ?commands show zrange
6220: ?set zrange
6221: ?show zrange
6222: ?zrange
6223: The `set zrange` command sets the range that will be displayed on the z axis.
6224: The zrange is used only by `splot` and is ignored by `plot`. Please see `set
6225: xrange` for details.
6226: 3 ztics
6227: ?commands set ztics
6228: ?commands set noztics
6229: ?commands show ztics
6230: ?set ztics
6231: ?set noztics
6232: ?show ztics
6233: ?ztics
6234: ?noztics
6235: The `set ztics` command controls major (labelled) tics on the z axis.
6236: Please see `set xtics` for details.
6237: 2 shell
6238: ?commands shell
6239: ?shell
6240: The `shell` command spawns an interactive shell. To return to `gnuplot`,
6241: type `logout` if using VMS, `exit` or the END-OF-FILE character if using
6242: Unix, `endcli` if using AmigaOS, or `exit` if using MS-DOS or OS/2.
6243:
6244: A single shell command may be spawned by preceding it with the ! character
6245: ($ if using VMS) at the beginning of a command line. Control will return
6246: immediately to `gnuplot` after this command is executed. For example, in
6247: Unix, AmigaOS, MS-DOS or OS/2,
6248:
6249: ! dir
6250:
6251: prints a directory listing and then returns to `gnuplot`.
6252:
6253: On an Atari, the `!` command first checks whether a shell is already loaded
6254: and uses it, if available. This is practical if `gnuplot` is run from
6255: `gulam`, for example.
6256: 2 splot
6257: ?commands splot
6258: ?splot
6259: `splot` is the command for drawing 3-d plots (well, actually projections on
6260: a 2-d surface, but you knew that). It can create a plot from functions or
6261: a data file in a manner very similar to the `plot` command.
6262:
6263: See `plot` for features common to the `plot` command; only differences are
6264: discussed in detail here. Note specifically that the `binary` and `matrix`
6265: options (discussed under "datafile-modifiers") are not available for `plot`.
6266:
6267: Syntax:
6268: splot {<ranges>}
6269: <function> | "<datafile>" {datafile-modifiers}}
6270: {<title-spec>} {with <style>}
6271: {, {definitions,} <function> ...}
6272:
6273: where either a <function> or the name of a data file enclosed in quotes is
6274: supplied. The function can be a mathematical expression, or a triple of
6275: mathematical expressions in parametric mode.
6276:
6277: By default `splot` draws the xy plane completely below the plotted data.
6278: The offset between the lowest ztic and the xy plane can be changed by `set
6279: ticslevel`. The orientation of a `splot` projection is controlled by
6280: `set view`. See `set view` and `set ticslevel` for more information.
6281:
6282: The syntax for setting ranges on the `splot` command is the same as for
6283: `plot`. In non-parametric mode, the order in which ranges must be given is
6284: `xrange`, `yrange`, and `zrange`. In parametric mode, the order is `urange`,
6285: `vrange`, `xrange`, `yrange`, and `zrange`.
6286:
6287: The `title` option is the same as in `plot`. The operation of `with` is also
6288: the same as in `plot`, except that the plotting styles available to `splot`
6289: are limited to `lines`, `points`, `linespoints`, `dots`, and `impulses`; the
6290: error-bar capabilities of `plot` are not available for `splot`.
6291:
6292: The datafile options have more differences.
6293: 3 data-file
6294: ?commands splot datafile
6295: ?splot datafile
6296: ?splot data-file
6297: As for `plot`, discrete data contained in a file can be displayed by
6298: specifying the name of the data file, enclosed in quotes, on the `splot`
6299: command line.
6300:
6301: Syntax:
6302: splot '<file_name>' {binary | matrix}
6303: {index <index list>}
6304: {every <every list>}
6305: {using <using list>}
6306:
6307: The special filenames `""` and `"-"` are permitted, as in `plot`.
6308:
6309: In brief, `binary` and `matrix` indicate that the the data are in a special
6310: form, `index` selects which data sets in a multi-data-set file are to be
6311: plotted, `every` specifies which datalines (subsets) within a single data
6312: set are to be plotted, and `using` determines how the columns within a single
6313: record are to be interpreted.
6314:
6315: The options `index` and `every` behave the same way as with `plot`; `using`
6316: does so also, except that the `using` list must provide three entries
6317: instead of two.
6318:
6319: The `plot` options `thru` and `smooth` are not available for `splot`, but
6320: `cntrparams` and `dgrid3d` provide limited smoothing cabilities.
6321:
6322: Data file organization is essentially the same as for `plot`, except that
6323: each point is an (x,y,z) triple. If only a single value is provided, it
6324: will be used for z, the datablock number will be used for y, and the index
6325: of the data point in the datablock will be used for x. If two values are
6326: provided, `gnuplot` gives you an error message. Three values are interpreted
6327: as an (x,y,z) triple. Additional values are generally used as errors, which
6328: can be used by `fit`.
6329:
6330: Single blank records separate datablocks in a `splot` datafile; `splot`
6331: treats datablocks as the equivalent of function y-isolines. No line will
6332: join points separated by a blank record. If all datablocks contain the same
6333: number of points, `gnuplot` will draw cross-isolines between datablocks,
6334: connecting corresponding points. This is termed "grid data", and is required
6335: for drawing a surface, for contouring (`set contour`) and hidden-line removal
6336: (`set hidden3d`). See also `splot grid data`
6337:
6338: It is no longer necessary to specify `parametric` mode for three-column
6339: `splot`s.
6340: 4 binary
6341: ?commands splot datafile binary
6342: ?splot datafile binary
6343: ?splot binary
6344: ?data-file binary
6345: ?datafile binary
6346: ?binary
6347: ?binary data
6348: ?binary files
6349: `splot` can read binary files written with a specific format (and on a
6350: system with a compatible binary file representation.)
6351:
6352: In previous versions, `gnuplot` dynamically detected binary data files. It
6353: is now necessary to specify the keyword `binary` directly after the filename.
6354:
6355: Single precision floats are stored in a binary file as follows:
6356:
6357: <N+1> <y0> <y1> <y2> ... <yN>
6358: <x0> <z0,0> <z0,1> <z0,2> ... <z0,N>
6359: <x1> <z1,0> <z1,1> <z1,2> ... <z1,N>
6360: : : : : ... :
6361:
6362: which are converted into triplets:
6363: <x0> <y0> <z0,0>
6364: <x0> <y1> <z0,1>
6365: <x0> <y2> <z0,2>
6366: : : :
6367: <x0> <yN> <z0,N>
6368:
6369: <x1> <y0> <z1,0>
6370: <x1> <y1> <z1,1>
6371: : : :
6372:
6373: These triplets are then converted into `gnuplot` iso-curves and then
6374: `gnuplot` proceeds in the usual manner to do the rest of the plotting.
6375:
6376: A collection of matrix and vector manipulation routines (in C) is provided
6377: in `binary.c`. The routine to write binary data is
6378:
6379: int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)
6380:
6381: An example of using these routines is provided in the file `bf_test.c`, which
6382: generates binary files for the demo file `demo/binary.dem`.
6383:
6384: The `index` keyword is not supported, since the file format allows only one
6385: surface per file. The `every` and `using` filters are supported. `using`
6386: operates as if the data were read in the above triplet form.
6387: ^ <a href="http://www.nas.nasa.gov/~woo/gnuplot/binary/binary.html">Binary File Splot Demo.</a>
6388: 4 example datafile
6389: ?commands splot datafile example
6390: ?splot datafile example
6391: ?splot example
6392: A simple example of plotting a 3-d data file is
6393:
6394: splot 'datafile.dat'
6395:
6396: where the file "datafile.dat" might contain:
6397:
6398: # The valley of the Gnu.
6399: 0 0 10
6400: 0 1 10
6401: 0 2 10
6402:
6403: 1 0 10
6404: 1 1 5
6405: 1 2 10
6406:
6407: 2 0 10
6408: 2 1 1
6409: 2 2 10
6410:
6411: 3 0 10
6412: 3 1 0
6413: 3 2 10
6414:
6415: Note that "datafile.dat" defines a 4 by 3 grid ( 4 rows of 3 points each ).
6416: Rows (datablocks) are separated by blank records.
6417:
6418: ^ <img align=bottom src="http://www.nas.nasa.gov/~woo/gnuplot/doc/splot.gif" alt="[splot.gif]" width=640 height=480>
6419: Note also that the x value is held constant within each dataline. If you
6420: instead keep y constant, and plot with hidden-line removal enabled, you will
6421: find that the surface is drawn 'inside-out'.
6422:
6423: Actually for grid data it is not necessary to keep the x values constant
6424: within a datablock, nor is it necessary to keep the same sequence of y
6425: values. `gnuplot` requires only that the number of points be the same for
6426: each datablock. However since the surface mesh, from which contours are
6427: derived, connects sequentially corresponding points, the effect of an
6428: irregular grid on a surface plot is unpredictable and should be examined
6429: on a case-by-case basis.
6430: 4 matrix
6431: ?commands splot datafile matrix
6432: ?splot datafile matrix
6433: ?splot matrix
6434: ?data-file matrix
6435: ?datafile matrix
6436: ?matrix
6437: The `matrix` flag indicates that the ASCII data are stored in matrix format.
6438: The z-values are read in a row at a time, i. e.,
6439: z11 z12 z13 z14 ...
6440: z21 z22 z23 z24 ...
6441: z31 z32 z33 z34 ...
6442: and so forth. The row and column indices are used for the x- and y-values.
6443: 3 grid_data
6444: ?commands splot grid_data
6445: ?splot grid_data
6446: ?grid_data
6447: The 3D routines are designed for points in a grid format, with one sample,
6448: datapoint, at each mesh intersection; the datapoints may originate from
6449: either evaluating a function, see `set isosamples`, or reading a datafile,
6450: see `splot datafile`. The term "isoline" is applied to the mesh lines for
6451: both functions and data. Note that the mesh need not be rectangular in x
6452: and y, as it may be parameterized in u and v, see `set isosamples`.
6453:
6454: However, `gnuplot` does not require that format. In the case of functions,
6455: 'samples' need not be equal to 'isosamples', i.e., not every x-isoline
6456: sample need intersect a y-isoline. In the case of data files, if there
6457: are an equal number of scattered data points in each datablock, then
6458: "isolines" will connect the points in a datablock, and "cross-isolines"
6459: will connect the corresponding points in each datablock to generate a
6460: "surface". In either case, contour and hidden3d modes may give different
6461: plots than if the points were in the intended format. Scattered data can be
6462: converted to a {different} grid format with `set dgrid3d`.
6463:
6464: The contour code tests for z intensity along a line between a point on a
6465: y-isoline and the corresponding point in the next y-isoline. Thus a `splot`
6466: contour of a surface with samples on the x-isolines that do not coincide with
6467: a y-isoline intersection will ignore such samples. Try:
6468: set xrange [-pi/2:pi/2]; set yrange [-pi/2:pi/2]
6469: set function style lp
6470: set contour
6471: set isosamples 10,10; set samples 10,10;
6472: splot cos(x)*cos(y)
6473: set samples 4,10; replot
6474: set samples 10,4; replot
6475:
6476: 3 splot_overview
6477: ?commands splot_overview
6478: ? splot_overview
6479: `splot` can display a surface as a collection of points, or by connecting
6480: those points. As with `plot`, the points may be read from a data file or
6481: result from evaluation of a function at specified intervals, see `set
6482: isosamples`. The surface may be approximated by connecting the points
6483: with straight line segments, see `set surface`, in which case the surface
6484: can be made opaque with `set hidden3d.` The orientation from which the 3d
6485: surface is viewed can be changed with `set view`.
6486:
6487: Additionally, for points in a grid format, `splot` can interpolate points
6488: having a common amplitude (see `set contour`) and can then connect those
6489: new points to display contour lines, either directly with straight-line
6490: segments or smoothed lines (see `set cntrparams`). Functions are already
6491: evaluated in a grid format, determined by `set isosamples` and `set samples`,
6492: while file data must either be in a grid format, as described in `data-file`,
6493: or be used to generate a grid (see `set dgrid3d`).
6494:
6495: Contour lines may be displayed either on the surface or projected onto the
6496: base. The base projections of the contour lines may be written to a
6497: file, and then read with `plot`, to take advantage of `plot`'s additional
6498: formatting capabilities.
6499: 2 test
6500: ?commands test
6501: ?test
6502: `test` creates a display of line and point styles and other useful things
6503: appropriate for the terminal you are using.
6504:
6505: Syntax:
6506: test
6507: 2 update
6508: ?commands update
6509: ?update
6510: This command writes the current values of the fit parameters into the given
6511: file, formatted as an initial-value file (as described in the `fit`section).
6512: This is useful for saving the current values for later use or for restarting
6513: a converged or stopped fit.
6514:
6515: Syntax:
6516: update <filename> {<filename>}
6517:
6518: If a second filename is supplied, the updated values are written to this
6519: file, and the original parameter file is left unmodified.
6520:
6521: Otherwise, if the file already exists, `gnuplot` first renames it by
6522: appending `.old` and then opens a new file. That is, "`update 'fred'`"
6523: behaves the same as "`!rename fred fred.old; update 'fred.old' 'fred'`".
6524: [On DOS and other systems that use the twelve-character "filename.ext"
6525: naming convention, "ext" will be "`old`" and "filename" will be related
6526: (hopefully recognizably) to the initial name. Renaming is not done at all
6527: on VMS systems, since they use file-versioning.]
6528:
6529: Please see `fit` for more information.
6530: 1 Graphical User Interfaces
6531: ?graphical user interfaces
6532: ?gui's
6533: Several graphical user interfaces have been written for `gnuplot` and one for
6534: win32 is included in this distribution. In addition, there is a Macintosh
6535: interface at
6536: ^<a href="ftp://ftp.ee.gatech.edu/pub/mac/gnuplot">
6537: ftp://ftp.ee.gatech.edu/pub/mac/gnuplot
6538: ^</a>
6539: and several X11 interfaces include three Tcl/Tk located at the usual Tcl/Tk
6540: repositories.
6541: 1 Bugs
6542: ?bugs
6543: Floating point exceptions (floating point number too large/small, divide by
6544: zero, etc.) may occasionally be generated by user defined functions. Some of
6545: the demos in particular may cause numbers to exceed the floating point range.
6546: Whether the system ignores such exceptions (in which case `gnuplot` labels
6547: the corresponding point as undefined) or aborts `gnuplot` depends on the
6548: compiler/runtime environment.
6549:
6550: The bessel functions do not work for complex arguments.
6551:
6552: The gamma function does not work for complex arguments.
6553:
6554: As of `gnuplot` version 3.7, all development has been done using ANSI C.
6555: With current operating system, compiler, and library releases, the OS
6556: specific bugs documented in release 3.5, now relegated to `old_bugs`, may
6557: no longer be relevant.
6558:
6559: Bugs reported since the current release may be located via the official
6560: distribution site:
6561: ftp://ftp.dartmouth.edu/pub/gnuplot
6562: http://www.cs.dartmouth.edu/gnuplot_info.html
6563:
6564: Please e-mail any bugs to bug-gnuplot@dartmouth.edu.
6565: 2 Old_bugs
6566: ?old_bugs
6567: ?os_bugs
6568: There is a bug in the stdio library for old Sun operating systems (SunOS
6569: Sys4-3.2). The "%g" format for 'printf' sometimes incorrectly prints numbers
6570: (e.g., 200000.0 as "2"). Thus, tic mark labels may be incorrect on a Sun4
6571: version of `gnuplot`. A work-around is to rescale the data or use the `set
6572: format` command to change the tic mark format to "%7.0f" or some other
6573: appropriate format. This appears to have been fixed in SunOS 4.0.
6574:
6575: Another bug: On a Sun3 under SunOS 4.0, and on Sun4's under Sys4-3.2 and
6576: SunOS 4.0, the 'sscanf' routine incorrectly parses "00 12" with the format
6577: "%f %f" and reads 0 and 0 instead of 0 and 12. This affects data input. If
6578: the data file contains x coordinates that are zero but are specified like
6579: '00', '000', etc, then you will read the wrong y values. Check any data
6580: files or upgrade the SunOS. It appears to have been fixed in SunOS 4.1.1.
6581:
6582: Suns appear to overflow when calculating exp(-x) for large x, so `gnuplot`
6583: gets an undefined result. One work-around is to make a user-defined function
6584: like e(x) = x<-500 ? 0 : exp(x). This affects plots of Gaussians (exp(-x*x))
6585: in particular, since x*x grows quite rapidly.
6586:
6587: Microsoft C 5.1 has a nasty bug associated with the %g format for 'printf'.
6588: When any of the formats "%.2g", "%.1g", "%.0g", "%.g" are used, 'printf' will
6589: incorrectly print numbers in the range 1e-4 to 1e-1. Numbers that should be
6590: printed in the %e format are incorrectly printed in the %f format, with the
6591: wrong number of zeros after the decimal point. To work around this problem,
6592: use the %e or %f formats explicitly.
6593:
6594: `gnuplot`, when compiled with Microsoft C, did not work correctly on two VGA
6595: displays that were tested. The CGA, EGA and VGA drivers should probably be
6596: rewritten to use the Microsoft C graphics library. `gnuplot` compiled with
6597: Borland C++ uses the Turbo C graphics drivers and does work correctly with
6598: VGA displays.
6599:
6600: VAX/VMS 4.7 C compiler release 2.4 also has a poorly implemented %g format
6601: for 'printf'. The numbers are printed numerically correct, but may not be in
6602: the requested format. The K&R second edition says that for the %g format, %e
6603: is used if the exponent is less than -4 or greater than or equal to the
6604: precision. The VAX uses %e format if the exponent is less than -1. The VAX
6605: appears to take no notice of the precision when deciding whether to use %e or
6606: %f for numbers less than 1. To work around this problem, use the %e or %f
6607: formats explicitly. From the VAX C 2.4 release notes: e,E,f,F,g,G Result
6608: will always contain a decimal point. For g and G, trailing zeros will not
6609: be removed from the result.
6610:
6611: VAX/VMS 5.2 C compiler release 3.0 has a slightly better implemented %g
6612: format than release 2.4, but not much. Trailing decimal points are now
6613: removed, but trailing zeros are still not removed from %g numbers in
6614: exponential format.
6615:
6616: The two preceding problems are actually in the libraries rather than in the
6617: compilers. Thus the problems will occur whether `gnuplot` is built using
6618: either the DEC compiler or some other one (e.g. the latest gcc).
6619:
6620: ULTRIX X11R3 has a bug that causes the X11 driver to display "every other"
6621: graph. The bug seems to be fixed in DEC's release of X11R4 so newer releases
6622: of ULTRIX don't seem to have the problem. Solutions for older sites include
6623: upgrading the X11 libraries (from DEC or direct from MIT) or defining
6624: ULTRIX_KLUDGE when compiling the x11.trm file. Note that the kludge is not
6625: an ideal fix, however.
6626:
6627: The constant HUGE was incorrectly defined in the NeXT OS 2.0 operating
6628: system. HUGE should be set to 1e38 in plot.h. This error has been corrected
6629: in the 2.1 version of NeXT OS.
6630:
6631: Some older models of HP plotters do not have a page eject command 'PG'. The
6632: current HPGL driver uses this command in HPGL_reset. This may need to be
6633: removed for these plotters. The current PCL5 driver uses HPGL/2 for text as
6634: well as graphics. This should be modified to use scalable PCL fonts.
6635:
6636: On the Atari version, it is not possible to send output directly to the
6637: printer (using `/dev/lp` as output file), since CRs are added to LFs in
6638: binary output. As a work-around, write the output to a file and copy it to
6639: the printer afterwards using a shell command.
6640:
6641: On AIX 4, the literal 'NaNq' in a datafile causes the special internal value
6642: 'not-a-number' to be stored, rather than setting an internal 'undefined'
6643: flag. A workaround is to use `set missing 'NaNq'`.
6644:
6645: There may be an up-to-date list of bugs since the release on the WWW page:
6646: http://www.cs.dartmouth.edu/gnuplot_info.html
6647:
6648: Please report any bugs to bug-gnuplot@dartmouth.edu.
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to gnuplot.doc CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [local] / OpenXM_contrib / gnuplot / docs