gnuplot

An Interactive Plotting Program

Thomas Williams & Colin Kelley

Version 3.5 organized by: Alex Woo

Version 3.6a organized by: Alexander Lehmann

Major contributors (alphabetic order):

   * John Campbell
   * Robert Cunningham
   * Gershon Elber
   * Roger Fearick
   * David Kotz
   * Ed Kubaitis
   * Russell Lang
   * Alexander Lehmann
   * Carsten Steger
   * Tom Tkacik
   * Jos Van der Woude
   * Alex Woo

Copyright (C) 1986 - 1993 Thomas Williams, Colin Kelley

Mailing list for comments: info-gnuplot@dartmouth.edu

Mailing list for bug reports: bug-gnuplot@dartmouth.edu

This manual is for GNUPLOT version 3.6a

---------------------------------------------------------------------------
Alex Woo, woo@playfair.stanford.edu
---------------------------------------------------------------------------

gnuplot

GNUPLOT is a command-driven interactive function plotting program.

For help on any topic, type help followed by the name of the topic.

The new GNUPLOT user should begin by reading the introduction topic (type
help introduction) and about the plot command (type help plot). Additional
help can be obtained from the USENET newsgroup comp.graphics.gnuplot.

copyright
introduction
cd
clear
command line-editing
comment
environment
exit
expressions
fit
help
if
load
call
pause
plot
print
pwd
quit
replot
reread
reset
save
set-show
shell
splot
start-up
substitution
update
user-defined
bugs
list of demos

---------------------------------------------------------------------------

copyright

     Copyright (C) 1986 - 1993   Thomas Williams, Colin Kelley

  Permission to use, copy, and distribute this software and its
  documentation for any purpose with or without fee is hereby granted,
  provided that the above copyright notice appear in all copies and
  that both that copyright notice and this permission notice appear
  in supporting documentation.

  Permission to modify the software is granted, but not the right to
  distribute the modified code.  Modifications are to be distributed
  as patches to released version.

  This software is provided "as is" without express or implied warranty.

  AUTHORS

    Original Software:
      Thomas Williams,  Colin Kelley.

    Gnuplot 2.0 additions:
        Russell Lang, Dave Kotz, John Campbell.

    Gnuplot 3.0 additions:
        Gershon Elber and many others.

  There is a mailing list for gnuplot users. Note, however, that the
  newsgroup
        comp.graphics.gnuplot
  is identical to the mailing list (they
  both carry the same set of messages). We prefer that you read the
  messages through that newsgroup, to subscribing to the mailing list.
  (If you can read that newsgroup, and are already on the mailing list,
  please send a message info-gnuplot-request@dartmouth.edu, asking to be
  removed from the mailing list.)

  The address for mailing to list members is
        info-gnuplot@dartmouth.edu
  and for mailing administrative requests is
        info-gnuplot-request@dartmouth.edu
  The mailing list for bug reports is
        bug-gnuplot@dartmouth.edu
  The list of those interested in beta-test versions is
        info-gnuplot-beta@dartmouth.edu

---------------------------------------------------------------------------

introduction

GNUPLOT is a command-driven interactive function plotting program. It is
case sensitive (commands and function names written in lowercase are not
the same as those written in CAPS). All command names may be abbreviated,
as long as the abbreviation is not ambiguous. Any number of commands may
appear on a line, separated by semicolons (;). Strings are indicated with
quotes. They may be either single or double quotation marks, e.g.,

         load "filename"
         cd 'dir'

Any command-line arguments are assumed to be names of files containing
GNUPLOT commands, with the exception of standard X11 arguments, which are
processed first. Each file is loaded with the load command, in the order
specified. GNUPLOT exits after the last file is processed. When no load
files are named, gnuplot enters into an interactive mode.

Commands may extend over several input lines, by ending each line but the
last with a backslash (\). The backslash must be the LAST character on each
line. The effect is as if the backslash and newline were not there. That
is, no white space is implied, nor is a comment terminated. Therefore,
commenting out a continued line comments out the entire command (see
comment).

In this documentation, curly braces ({}) denote optional arguments to many
commands, and a vertical bar (|) separates mutually exclusive choices.
GNUPLOT keywords or help topics are indicated by backquotes or boldface
(where available). Angle brackets (<>) are used to mark replaceable tokens.

For help on any topic, type help followed by the name of the topic.

The new GNUPLOT user should begin by reading about the plot command (type
help plot). Simple Plots Demo

---------------------------------------------------------------------------

cd

The cd command changes the working directory.

Syntax:

        cd "<directory-name>"

The directory name must be enclosed in quotes.

Examples:

        cd 'subdir'
        cd ".."

---------------------------------------------------------------------------

clear

The clear command erases the current screen or output device as specified
by set output. This usually generates a formfeed on hardcopy devices. Use
set terminal to set the device type.

---------------------------------------------------------------------------

command line-editing

The Unix, Atari, VMS, MS-DOS and OS/2 versions of GNUPLOT support command
line-editing. Also, a history mechanism allows previous commands to be
edited, and re-executed. After the command line has been edited, a newline
or carriage return will enter the entire line regardless of where the
cursor is positioned.

The editing commands are as follows:

 Line-editing:

 ^B moves back a single character.
 ^F moves forward a single character.
 ^A moves to the beginning of the line.
 ^E moves to the end of the line.
 ^H and DEL delete the previous character.
 ^D deletes the current character.
 ^K deletes from current position to the end of line.
 ^L,^R redraws line in case it gets trashed.
 ^U deletes the entire line.
 ^W deletes the last word.

 History:

 ^P moves back through history.
 ^N moves forward through history.

On the IBM PC the use of a TSR program such as DOSEDIT or CED may be
desired for line editing. For such a case GNUPLOT may be compiled with no
line editing capability (default makefile setup). Set READLINE in the
makefile and add readline.obj to the link file if GNUPLOT line editing is
to be used for the IBM PC. The following arrow keys may be used on the IBM
PC and Atari versions if readline is used:

 Left  Arrow     - same as ^B.
 Right Arrow     - same as ^F.
 Ctl Left  Arrow - same as ^A.
 Ctl Right Arrow - same as ^E.
 Up    Arrow     - same as ^P.
 Down  Arrow     - same as ^N.

The Atari version of readline defines some additional key aliases:

 Undo            - same as ^L.
 Home            - same as ^A.
 Ctrl Home       - same as ^E.
 ESC             - same as ^U.
 Help            - help' plus return.
 Ctrl Help       - help '.

(The readline function in gnuplot is not the same as the readline used in
GNU BASH and GNU EMACS. It is somewhat compatible however.)

---------------------------------------------------------------------------

comment

Comments are supported as follows: a # may appear in most places in a line
and GNUPLOT will ignore the rest of the line. It will not have this effect
inside quotes, inside numbers (including complex numbers), inside command
substitutions, etc. In short, it works anywhere it makes sense to work.

---------------------------------------------------------------------------

environment

A number of shell environment variables are understood by GNUPLOT. None of
these are required, but may be useful.

If GNUTERM is defined, it is used as the name of the terminal type to be
used. This overrides any terminal type sensed by GNUPLOT on start up, but
is itself overridden by the .gnuplot (or equivalent) start-up file (see
start-up), and of course by later explicit changes.

On Unix, AmigaDOS, AtariTOS, MS-DOS and OS/2, GNUHELP may be defined to be
the pathname of the HELP file (gnuplot.gih).

On VMS, the symbol GNUPLOT$HELP should be defined as the name of the help
library for GNUPLOT.

On Unix, HOME is used as the name of a directory to search for a .gnuplot
file if none is found in the current directory. On AmigaDOS, AtariTOS,
MS-DOS and OS/2, GNUPLOT is used. On VMS, SYS$LOGIN: is used. See help
start-up.

On Unix, PAGER is used as an output filter for help messages.

On Unix, AtariTOS and AmigaDOS, SHELL is used for the shell command. On
MS-DOS and OS/2, COMSPEC is used for the shell command.

On AmigaDOS, GNUFONT is used for the screen font. For example: "setenv
GNUFONT sapphire/14".

On MS-DOS, if the BGI interface is used, the variable BGI is used to point
to the full path of the BGI drivers directory. Furthermore SVGA is used to
name the Super VGA BGI driver in 800x600 res., and its mode of operation as
'Name.Mode'. E.g., if the Super VGA driver is C:\TC\BGI\SVGADRV.BGI and
mode 3 is used for 800x600 res., then: 'set BGI=C:\TC\BGI' and 'set
SVGA=SVGADRV.3'.

---------------------------------------------------------------------------

exit

The commands exit and quit and the END-OF-FILE character will exit GNUPLOT.
All these commands will clear the output device (as the clear command does)
before exiting.

---------------------------------------------------------------------------

expressions

In general, any mathematical expression accepted by C, FORTRAN, Pascal, or
BASIC is valid. The precedence of these operators is determined by the
specifications of the C programming language. White space (spaces and tabs)
is ignored inside expressions.

Complex constants may be expressed as the {<real>,<imag>}, where <real> and
<imag> must be numerical constants. For example, {3,2} represents 3 + 2i;
{0,1} represents i itself. The curly braces are explicitly required here.

functions
operators

---------------------------------------------------------------------------

functions

The functions in GNUPLOT are the same as the corresponding functions in the
Unix math library, except that all functions accept integer, real, and
complex arguments, unless otherwise noted. The sgn function is also
supported, as in BASIC.

abs
acos
arg
asin
atan
besj0
besj1
besy0
besy1
ceil
cos
cosh
erf
erfc
exp
floor
gamma
ibeta
inverf
igamma
imag
invnorm
int
lgamma
log
log10
norm
rand
real
sgn
sin
sinh
sqrt
tan
tanh

---------------------------------------------------------------------------

abs

The abs function returns the absolute value of its argument. The returned
value is of the same type as the argument.

For complex arguments, abs(x) is defined as the length of x in the complex
plane [i.e., sqrt(real(x)**2 + imag(x)**2) ].

---------------------------------------------------------------------------

acos

The acos function returns the arc cosine (inverse cosine) of its argument.
acos returns its argument in radians.

---------------------------------------------------------------------------

arg

The arg function returns the phase of a complex number, in radians.

---------------------------------------------------------------------------

asin

The asin function returns the arc sin (inverse sin) of its argument. asin
returns its argument in radians.

---------------------------------------------------------------------------

atan

The atan function returns the arc tangent (inverse tangent) of its
argument. atan returns its argument in radians.

---------------------------------------------------------------------------

besj0

The besj0 function returns the j0th Bessel function of its argument. besj0
expects its argument to be in radians.

---------------------------------------------------------------------------

besj1

The besj1 function returns the j1st Bessel function of its argument. besj1
expects its argument to be in radians.

---------------------------------------------------------------------------

besy0

The besy0 function returns the y0th Bessel function of its argument. besy0
expects its argument to be in radians.

---------------------------------------------------------------------------

besy1

The besy1 function returns the y1st Bessel function of its argument. besy1
expects its argument to be in radians.

---------------------------------------------------------------------------

ceil

The ceil function returns the smallest integer that is not less than its
argument. For complex numbers, ceil returns the smallest integer not less
than the real part of its argument.

---------------------------------------------------------------------------

cos

The cos function returns the cosine of its argument. cos expects its
argument to be in radians.

---------------------------------------------------------------------------

cosh

The cosh function returns the hyperbolic cosine of its argument. cosh
expects its argument to be in radians.

---------------------------------------------------------------------------

erf

The erf function returns the error function of the real part of its
argument. If the argument is a complex value, the imaginary component is
ignored.

---------------------------------------------------------------------------

erfc

The erfc function returns 1.0 - the error function of the real part of its
argument. If the argument is a complex value, the imaginary component is
ignored.

---------------------------------------------------------------------------

exp

The exp function returns the exponential function of its argument (e raised
to the power of its argument).

---------------------------------------------------------------------------

floor

The floor function returns the largest integer not greater than its
argument. For complex numbers, floor returns the largest integer not
greater than the real part of its argument.

---------------------------------------------------------------------------

gamma

The gamma function returns the gamma function of the real part of its
argument. For integer n, gamma(n+1) = n! . If the argument is a complex
value, the imaginary component is ignored.

---------------------------------------------------------------------------

ibeta

The ibeta function returns the incomplete beta function of the real parts
of its arguments. p, q > 0 and x in [0:1] If the arguments are complex, the
imaginary components are ignored.

---------------------------------------------------------------------------

inverf

The inverf function returns the inverse error function of the real part of
its argument.

---------------------------------------------------------------------------

igamma

The igamma function returns the incomplete gamma function of the real parts
of its arguments. a > 0 and x >= 0 If the arguments are complex, the
imaginary components are ignored.

---------------------------------------------------------------------------

imag

The imag function returns the imaginary part of its argument as a real
number.

---------------------------------------------------------------------------

invnorm

The invnorm function returns the inverse normal distribution function of
the real part of its argument.

---------------------------------------------------------------------------

int

The int function returns the integer part of its argument, truncated toward
zero.

---------------------------------------------------------------------------

lgamma

The lgamma function returns the natural logarithm of the gamma function of
the real part of its argument. If the argument is a complex value, the
imaginary component is ignored.

---------------------------------------------------------------------------

log

The log function returns the natural logarithm (base e) of its argument.

---------------------------------------------------------------------------

log10

The log10 function returns the logarithm (base 10) of its argument.

---------------------------------------------------------------------------

norm

The norm function returns the normal distribution function (or Gaussian) of
the real part of its argument.

---------------------------------------------------------------------------

rand

The rand function returns a pseudo random number in the interval [0:1]
using the real part of its argument as a seed. If seed < 0 the sequence is
(re)initialized. If the argument is a complex value, the imaginary
component is ignored.

---------------------------------------------------------------------------

real

The real function returns the real part of its argument.

---------------------------------------------------------------------------

sgn

The sgn function returns 1 if its argument is positive, -1 if its argument
is negative, and 0 if its argument is 0. If the argument is a complex
value, the imaginary component is ignored.

---------------------------------------------------------------------------

sin

The sin function returns the sine of its argument. sin expects its argument
to be in radians.

---------------------------------------------------------------------------

sinh

The sinh function returns the hyperbolic sine of its argument. sinh expects
its argument to be in radians.

---------------------------------------------------------------------------

sqrt

The sqrt function returns the square root of its argument.

---------------------------------------------------------------------------

tan

The tan function returns the tangent of its argument. tan expects its
argument to be in radians.

---------------------------------------------------------------------------

tanh

The tanh function returns the hyperbolic tangent of its argument. tanh
expects its argument to be in radians. Use of functions and complex
variables for airfoils

---------------------------------------------------------------------------

operators

The operators in GNUPLOT are the same as the corresponding operators in the
C programming language, except that all operators accept integer, real, and
complex arguments, unless otherwise noted. The ** operator (exponentiation)
is supported, as in FORTRAN.

Parentheses may be used to change order of evaluation.

binary
unary

---------------------------------------------------------------------------

binary

The following is a list of all the binary operators and their usages:

 Symbol      Example      Explanation
  **          a**b          exponentiation
  *           a*b           multiplication
  /           a/b           division
  %           a%b         * modulo
  +           a+b           addition
  -           a-b           subtraction
  ==          a==b          equality
  !=          a!=b          inequality
  &           a&b         * bitwise AND
  ^           a^b         * bitwise exclusive OR
  |           a|b         * bitwise inclusive OR
  &&          a&&b        * logical AND
  ||          a||b        * logical OR
  ?:          a?b:c       * ternary operation

(*) Starred explanations indicate that the operator requires integer
arguments.

Logical AND (&&) and OR (||) short-circuit the way they do in C. That is,
the second && operand is not evaluated if the first is false; the second ||
operand is not evaluated if the first is true.

The ternary operator evaluates its first argument (a). If it is true
(non-zero) the second argument (b) is evaluated and returned, otherwise the
third argument (c) is evaluated and returned.

---------------------------------------------------------------------------

unary

The following is a list of all the unary operators and their usages:

 Symbol     Example      Explanation
  -           -a          unary minus
  ~           ~a        * one's complement
  !           !a        * logical negation
  !           a!        * factorial

(*) Starred explanations indicate that the operator requires an integer
argument.

The factorial operator returns a real number to allow a greater range.

---------------------------------------------------------------------------

fit

This implementation incorporates the capabiblity of nonlinear least squares
fit by using the Marquardt-Levenberg-Algorithm. It may fit every
user-defined function to any set of data pairs (x,y). x, y and the
function's return type MUST be real! Any variable occuring in the function
body may serve as fit parameter (fitting functions without adjustable
parameters make no sense). The syntax is:

   fit <function> <datafile> {using x:y{:dy}} <parameter file>     or
   fit <function> <datafile> {using x:y{:dy}} via <var1>, <var2>, ...

<function> is a previously user-defined function of the form: f(x)
<datafile> is treated as in the plot-command. The default column for x is
1, for y is 2. They may be changed by the using x:y mechanism. The optional
dy specifies a column containing individual uncertainties for each y-value.
These will then be used as weights during the fit. If they aren't given all
uncertainties are assumed equally distributed. The start parameters may be
specified in a (load-) file wherein each line is of the form:

   varname = value

(comments, separated by '#' and blank lines are also possible). The form

   varname = value       # FIXED

means that the variable is treated as a fixed parameter that is initialized
but will not be adjusted. It is not necessary (but sometimes useful for
clarity) to specify them at all. The keyword '# FIXED' has to appear in
exactly this form. The other possibility of specifying start values is that
the current value of a variable during the GNUPLOT session shall serve as
start parameter. In this case the syntax including the via keyword may be
used where only the adjustable variables' names must be given.

After each iteration step a detailed info is given about the fit's state
both on the screen and on a logfile "fit.log". This file will never be
erased but always appended so that the fit's history isn't lost. After each
iteration step the fit may be interrupted by pressing ctrl-C (any key BUT
ctrl-C under MSDOS). Then you have the possibility of stopping (and
accepting the current parameter values) or continuing the fit or of
executing a gnuplot command specified by an environment variable
FIT_SCRIPT. E.g. a plot command or LOADing some file may be useful.

Special GNUPLOT variables:

   FIT_INDEX: This variable always contains the current data point number
              during execution starting with 1. You may use it in your fit
              function to implement multiple-branch-fits.
   FIT_SKIP:  You may specify a positive integer to always skip i data points
              during fitting. This increases execution speed by the
              price of less exact results.
   FIT_LIMIT: may be specified to change the default epsilon limit (1e-5).
              When the sum of squared residuals changes between 2 iteration
              steps by less than a factor of this number, the fit is
              considered as 'converged'.

 Environment variables:
   FIT_LOG    changes the logfile's path from './fit.log' (write permission
              is necessary).
   FIT_SCRIPT specifies a command to be executed after an user interrupt

 Examples:
   f(x) = a*x**2 + b*x + c
   fit f(x) 'measured.dat' 'start.par'
   fit f(x) 'measured.dat' using 3:7 'start.par'
   fit f(x) './data/trash.dat' using 1:2:3 via a, b, c

 SEE ALSO: update

---------------------------------------------------------------------------

help

The help command displays on-line help. To specify information on a
particular topic use the syntax:

        help {<topic>}

If <topic> is not specified, a short message is printed about GNUPLOT.
After help for the requested topic is given, help for a subtopic may be
requested by typing its name, extending the help request. After that
subtopic has been printed, the request may be extended again, or simply
pressing return goes back one level to the previous topic. Eventually, the
GNUPLOT command line will return.

---------------------------------------------------------------------------

if

The if command allows commands to be executed conditionally.

Syntax:

        if (<condition>) <command-line>

The <condition> will be evaluated, if it is true (non-zero), then the
command(s) of the <command-line> will be executed. If the <condition> is
false (equals zero), then the entire <command-line> is ignored. Note that
use of ';' to allow multiple commands on the same line will NOT end the
conditionalized commands.

Examples:

     pi=3
     if (pi!=acos(-1)) pause 0 "?Fixing pi!";pi=acos(-1);show variables

will display:

     ?Fixing pi!

             Variables:
             pi = 3.14159

or

     if (1==2) pause 0 "Never see this";pause 0 "Or this either"

will not display anything.

---------------------------------------------------------------------------

load

The load command executes each line of the specified input file as if it
had been typed in interactively. Files created by the save command can
later be loaded. Any text file containing valid commands can be created and
then executed by the load command. Files being loaded may themselves
contain load (or call) commands. See comment for information about comments
in commands.

The load command must be the last command on the line.

Syntax:

        load "<input-file>"

The name of the input file must be enclosed in quotes.

Examples:

        load 'work.gnu'
        load "func.dat"

The load command is performed implicitly on any file names given as
arguments to GNUPLOT. These are loaded in the order specified, and then
GNUPLOT exits.

---------------------------------------------------------------------------

call

The call command is identical to the load command with one exception: you
can have up to 10 additional parameters to the command (delimited according
to the standard parser rules) which can be substituted into the lines read
from the file. As each line is read from the called input-file it is
scanned for the sequence $ (dollar-sign) followed by a digit (0-9). If
found, the sequence is replaced by the corresponding parameter from the
call command line. If the parameter was specified as a string in the call
line, it is substituted without its enclosing quotes. $ followed by any
character other than a digit will be that character. (E.g. use $$ to get a
single $.) Providing more than 10 parameters on the call command line will
cause an error. A parameter that was not provided, substitutes as nothing.
Files being called may themselves contain call or load commands.

The call command must be the last command on the line.

Syntax:

        call "<input-file>" <parameter-0> <parm-1> ... <parm-9>

The name of the input file must be enclosed in quotes.

Examples:

if the file 'calltest.gp' contains the line:
    pause 0 "p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"

entering the command:

    call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"

will display:

    p0=abcd p1=1.2 p2=+ p3='quoted' p4=- p5=- p6=$2 p7=xx

---------------------------------------------------------------------------

pause

The pause command displays any text associated with the command and then
waits a specified amount of time or until the carriage return is pressed.
pause is especially useful in conjunction with load files.

Syntax:

        pause <time> {"<string>"}

<time> may be any integer constant or expression. Choosing -1 will wait
until a carriage return is hit, zero (0) won't pause at all, and a positive
integer will wait the specified number of seconds.

Note: Since pause is not part of the plot it may interact with different
device drivers differently (depending upon how text and graphics are
mixed).

Examples:

        pause -1    # Wait until a carriage return is hit
        pause 3     # Wait three seconds
        pause -1  "Hit return to continue"
        pause 10  "Isn't this pretty?  It's a cubic-spline."

---------------------------------------------------------------------------

plot

plot and splot are the primary commands of the program. They plot functions
and data in many, many ways. plot is used to plot 2-d functions and data,
while splot plots 3-d surfaces and data.

Syntax:

       plot {ranges} {<function> | {"<datafile>" {using ...}}}
                    {title} {style} {, <function> {title} {style}...}

       splot {ranges} {<function> | {"<datafile>" {index i} {using ...}}}
                    {title} {style} {, <function> {title} {style}...}

where either a <function> or the name of a data file enclosed in quotes is
supplied. A function is a mathematical expression, or a pair (plot) or
triple (splot) of mathematical expressions in the case of parametric
functions. User-defined functions and variables may also be defined here.

plot and splot commands can be as simple as

        plot sin(x)

and

        splot x * y

or as complex as (!)

 plot [t=1:10] [-pi:pi*2] tan(t), "data.1" using 2:3 with lines,
       t**2 with points

data-file
errorbars
parametric
ranges
index
style
title

---------------------------------------------------------------------------

data-file

Discrete data contained in a file can be displayed by specifying the name
of the data file (enclosed in quotes) on the plot or splot command line.
Data files should contain one data point per line. Lines beginning with #
(or ! on VMS) will be treated as comments and ignored. For plots, each data
point represents an (x,y) pair. For splots, each point is an (x,y,z)
triple. For plots with error bars (see plot errorbars), each data point is
either (x,y,ydelta), (x,y,ylow,yhigh), (x,y,xdelta), (x,y,xlow,xhigh), or
(x,y,xlow,xhigh,ylow,yhigh). In all cases, the numbers on each line of a
data file must be separated by blank space. This blank space divides each
line into columns.

For plots the x value may be omitted, and for splots the x and y values may
be omitted. In either case the omitted values are assigned the current
coordinate number. Coordinate numbers start at 0 and are incremented for
each data point read.

To specify other formats, see plot datafile using.

In the plot command, blank lines in the data file cause a break in the
plot. There will be no line drawn between the preceding and following
points if the plot style is lines or linespoints (see plot style). This
does not change the plot style, as would plotting the data as separate
curves.

This example compares the data in the file population.dat to a theoretical
curve:

        pop(x) = 103*exp((1965-x)/10)
        plot [1960:1990] 'population.dat', pop(x)

The file population.dat might contain:

        # Gnu population in Antarctica since 1965
        1965   103
        1970   55
        1975   34
        1980   24
        1985   10

When a data file is plotted, samples and isosamples are ignored. Curves
plotted using the plot command are automatically extended to hold the
entire curve. Similarly grid data plotted using the splot command is
automatically extended, using the assumption that isolines are separated by
blank lines (a line with only a CR/LF in it).

Implicitly, there are two types of 3-d datafiles. If all the isolines are
of the same length, the data is assumed to be a grid data, i.e., the data
has a grid topology. Cross isolines in the other parametric direction (the
ith cross isoline passes through the ith point of all the provided
isolines) will also be drawn for grid data. (Note contouring is available
for grid data only.) If all the isolines are not of the same length, no
cross isolines will be drawn and contouring that data is impossible.

For splot, data files may contain more than one mesh and by default all
meshes are plotted. Meshes are separated from each other, in the file, by
double blank lines. To control and splot a single mesh from a multi mesh
file, use the index modifier. See splot index for more.

For splot if 3-d datafile and using format (see splot datafile using)
specify only z (height field), a non parametric mode must be specified. If,
on the other hand, x, y, and z are all specified, a parametric mode should
be selected (see set parametric) since data is defining a parametric
surface.

A simple example of plotting a 3-d data file is

        set parametric
        splot 'glass.dat'

or

        set noparametric
        splot 'datafile.dat'

where the file datafile.dat might contain:

        # The valley of the Gnu.
        10
        10
        10

        10
        5
        10

        10
        1
        10

        10
        0
        10

Note datafile.dat defines a 4 by 3 grid ( 4 rows of 3 points each ). Rows
are separated by blank lines.

On some computer systems with a popen function (UNIX), the datafile can be
piped through a shell command by starting the file name with a '<'. For
example:

        pop(x) = 103*exp(-x/10)
        plot "< awk '{print $1-1965, $2}' population.dat", pop(x)

would plot the same information as the first population example but with
years since 1965 as the x axis. If you want to execute this example, you
have to delete all comments from the data file above or substitute the
following command for the first part of the command above (the part up to
the comma):

        plot "< awk '$0 !~ /^#/ {print $1-1965, $2}' population.dat"

It is also possible to apply a single function to the "y" value only, e.g.

        plot 'population.dat' thru p(x)

For more information about 3-d plotting, see splot. Simple Plot Demos ,
Non-parametric splot demos , and Parametric splot demos.

using

---------------------------------------------------------------------------

using

The format of data within a file can be selected with the using option. An
explicit scanf string can be used, or simpler column choices can be made.

Syntax:

        plot "datafile" { using { <ycol> |
                                  <xcol>:<ycol> |
                                  <xcol>:<ycol>:<ydelta> |
                                  <xcol>:<ycol>:<xdelta> |
                                  <xcol>:<ycol>:<boxwidth> |
                                  <xcol>:<ycol>:<ylow>:<yhigh> |
                                  <xcol>:<ycol>:<xlow>:<xhigh> |
                                  <xcol>:<ycol>:<xdelta>:<ydelta> |
                                  <xcol>:<ycol>:<ydelta>:<boxwidth> |
                                  <xcol>:<ycol>:<ylow>:<yhigh>:<boxwidth> |
                                  <xcol>:<ycol>:<xlow>:<xhigh>:<ylow>:<yhigh>}
                                {"<scanf string>"} } ...

and

        splot "datafile" { using { <xcol>:<ycol>:<zcol> | <zcol> }
                                 {"<scanf string>"} } ...

<xcol>, <ycol>, and <zcol> explicitly select the columns to plot from a
space or tab separated multicolumn data file. If only <ycol> is selected
for plot, <xcol> defaults to 1. If only <zcol> is selected for splot, then
only that column is read from the file. An <xcol> of 0 forces <ycol> to be
plotted versus its coordinate number. <xcol>, <ycol>, and <zcol> can be
entered as constants or expressions.

If x, y and/or z is time data (dates-times), the columns occupied by the
time (any character, spaces included, is allowed in format string) counts
for one column. The "scanf-string" will not work with timeseries. See also
set timefmt. Time Data Demo

If yerrorbars (see also plot errorbars) are used for plots, ydelta (for
example, a +/- error) should be provided as the third column, or ylow and
yhigh as third and fourth columns.

If xerrorbars (see also plot errorbars) are used for plots, xdelta (for
example, a +/- error) should be provided as the third column, or xlow and
xhigh as third and fourth columns.

If xyerrorbars or boxxyerrorbars (see also plot errorbars) are used for
plots, xlow and xhigh may be provided as third and fourth columns and ylow
and yhigh may be provided as fifth and sixth columns. It is also possible
to have xdelta and ydelta in the third and fourth columns, respectively.

If boxes are used for plots, the third column is used to specify the width
of the box. If boxerrorbars are used, the fourth column (if "ydelta" is
third col), or the fifth column (if "ylow" and "yhigh" are third and fourth
cols) may be used for the box width. See boxerrorbars or set style for more
details. Note that boxerrorbars is only used for data with errors in y.
Each box starts at the x axis (boxxyerrorbars has different behavior).
Errorbar demos.

Scanf strings override any <xcol>:<ycol>(:<zcol>) choices, except for
ordering of input, e.g.,

        plot "datafile" using 2:1 "%lf%*lf%lf"

causes the first column to be y and the third column to be x.

If the scanf string is omitted, the default is generated based on the
<xcol>:<ycol>(:<zcol>) choices. If the using option is omitted, "%lf%lf" is
used for plot ("%lf%lf%lf%lf" for errorbars plots) and "%lf%lf%lf" is used
for splot.

Examples:

        plot "MyData" using "%*lf%lf%*20[^\n]%lf" with lines

Data are read from the file "MyData" using the format
"%*lf%lf%*20[^\n]%lf". The meaning of this format is: "%*lf" ignore the
first number, "%lf" then read in the second and assign to x, "%*20[^\n]"
then ignore 20 non-newline characters, "%lf" then read in the y value.

        n=3;
        plot "MyData", "MyData" using n

causes GNUPLOT to plot the second and third columns of MyData versus the
first column. The command 'n=4; replot' would then plot the second and
fourth columns of MyData versus the first column.

        splot "glass.dat" using 1

causes GNUPLOT to plot the first coordinate of the points of glass.dat as
the z coordinate while ignoring the other two coordinates.

Note: GNUPLOT first reads a line of the data file into a buffer and then
does a

        sscanf(input_buffer, scanf_string, &x, &y{, &z});

where 'x', 'y', and 'z' are of type 'float'. Any scanf string that
specifies two (three for splot, three to six for errorbars) float numbers
may be used. Using Demos.

---------------------------------------------------------------------------

errorbars

Error bars are supported for 2-d data file plots by reading one to four
additional columns specifying ydelta or ylow and yhigh for yerrorbars or
xdelta or xlow and xhigh for xerrorbars or xdelta, ydelta or xlow, xhigh,
ylow, yhigh for xyerrorbars or boxxyerrorbars. No support exists for any
error bars for splots.

In the default situation, GNUPLOT expects to see three or six numbers on
each line of the data file, either (x, y, ydelta), (x, y, ylow, yhigh), (x,
y, xdelta), (x, y, xlow, xhigh), (x, y, xdelta, ydelta), or (x, y, xlow,
xhigh, ylow, yhigh). The x coordinate must be specified. The order of the
numbers must be exactly as given above. Data files in this format can
easily be plotted with error bars:

        plot "data.dat" with errorbars (or yerrorbars)
        plot "data.dat" with xerrorbars
        plot "data.dat" with xyerrorbars
        plot "data.dat" with yerrorbars

The y-error bar is a vertical line plotted from (x, ylow) to (x, yhigh). If
ydelta is specified instead of ylow and yhigh, ylow=y-ydelta and
yhigh=y+ydelta are derived. If there are only two numbers on the line,
yhigh and ylow are both set to y. The x-error bar is a horizontal line
computed in the same fashion. To get lines plotted between the data points,
plot the data file twice, once with errorbars and once with lines.

If autoscaling is on, the x and/or y range will be adjusted to fit the
error bars.

The using option may be used to specify how columns of the data file are to
be assigned to x, y, ydelta, ylow and yhigh, xdelta, xlow and xhigh. The x
column must be provided and both the x and y columns must appear before the
errorbar columns. If three column numbers are given, they are x, y, and
ydelta or xdelta. If four columns are given, they are x, y, ylow, and yhigh
or x, y, xlow, and xhigh or x, y, xdelta, ydelta.

Examples:

        plot "data.dat" using 1:2:3:4 with errorbars (or yerrorbars)
        plot "data.dat" using 3:2:6 with xerrorbars
        plot "data.dat" using 3:4:8:7 with xyerrorbars

The first example reads, x, y, ylow, and yhigh, from columns 1, 2, 3, and
4. This is equivalent to the default. The second example reads x from the
third column, y from second and xdelta from the sixth column. The third
example reads x from the third column, y from the fourth, xdelta from the
eighth, and ydelta from seventh columns. Errorbar demos.

See also plot using and plot style.

---------------------------------------------------------------------------

parametric

When in parametric mode (set parametric) mathematical expressions must be
given in pairs for plot and in triplets for splot:

        plot sin(t),t**2

or

        splot cos(u)*cos(v),cos(u)*sin(v),sin(u)

Data files are plotted as before, except any preceding parametric function
must be fully specified before a data file is given as a plot. In other
words, the x parametric function (sin(t) above) and the y parametric
function (t**2 above) must not be interrupted with any modifiers or data
functions; doing so will generate a syntax error stating that the
parametric function is not fully specified.

Ranges take on a different meaning when in parametric mode. The first range
on the plot command is the trange, the next is the xrange, and the last is
the yrange. For splot the order is urange, vrange, xrange, yrange, and
finally zrange. The following plot command shows setting the trange to
[-pi:pi], the xrange to [-1.3:1.3] and the yrange to [-1:1] for the
duration of the plot:

        plot [-pi:pi] [-1.3:1.3] [-1:1] sin(t),t**2

Other modifiers, such as with and title, may be specified only after the
parametric function has been completed:

        plot sin(t),t**2 title 'Parametric example' with linespoints

e.g. Parametric Mode Demos.

---------------------------------------------------------------------------

ranges

The optional range specifies the region of the plot that will be displayed.

Ranges may be provided on the plot and splot command line and affect only
that plot, or in the set xrange, set yrange, etc., commands, to change the
default ranges for future plots.

Syntax:

        [{<dummy-var> =} {<xmin> : <xmax>}] { [{<ymin> : <ymax>}] }

where <dummy-var> is the independent variable (the defaults are x and y,
but this may be changed with set dummy) and the min and max terms can be
constant expressions. If only one value is provided (as in: set yrange
[0:]) the range in the opposite direction is unaffected (or still
autoscaled). To set a range back to autoscale give a star as the value (set
yrange [*:] turns autoscaling in the ymin direction on).

Both the min and max terms are optional. The ':' is also optional if
neither a min nor a max term is specified. This allows '[ ]' to be used as
a null range specification.

Specifying a range in the plot command line turns autoscaling for that axis
off for that plot. Using one of the set range commands turns autoscaling
off for that axis for future plots, unless changed later. (See set
autoscale).

With time data, provide the ranges in the samme manner as in the datafile
within quotes (uses the timefmt string to read the value).

Examples:

This uses the current ranges:

        plot cos(x)

This sets the x range only:

        plot [-10:30] sin(pi*x)/(pi*x)

This is the same, but uses t as the dummy-variable:

        plot [t = -10 :30]  sin(pi*t)/(pi*t)

This sets both the x and y ranges:

        plot [-pi:pi] [-3:3]  tan(x), 1/x

This sets only the y range, and turns off autoscaling on both axes:

        plot [ ] [-2:sin(5)*-8] sin(x)**besj0(x)

This sets xmax and ymin only:

        plot [:200] [-pi:]  exp(sin(x))

This sets the x, y, and z ranges:

        splot [0:3] [1:4] [-1:1] x*y

Timeseries (timefmt="%d/%m/%y %H:%M"):

        set xrange ["1/6/93 12:00":"5/6/93 12:00"]

---------------------------------------------------------------------------

index

Splotting of multi mesh data files can be controlled via the index
modifier. A data file can contain more than one mesh, and in that case all
meshes in the file will be splotted by default. Meshes are separated from
each other, in the data file, by double blank lines. To splot a single mesh
in a multi mesh file use the index modifier which specify which mesh to
splot. First mesh is mesh 0.

Example:

splot "data1" index 2 with points

will splot the third mesh in file data1 with points. splot with indices
demo.

---------------------------------------------------------------------------

style

Plots may be displayed in one of thirteen styles: lines, points,
linespoints, impulses, dots, {x,y,xy}errorbars, steps, fsteps, boxes,
boxerrorbars, or boxxyerrorbars. The lines style connects adjacent points
with lines. The points style displays a small symbol at each point. The
linespoints style does both lines and points. The impulses style displays a
vertical line from the x axis (or from the grid base for splot) to each
point. The dots style plots a tiny dot at each point; this is useful for
scatter plots with many points.

The errorbars (or yerrorbars) and xerrorbars styles are only relevant to
2-d data file plotting. It is treated like points for splots and function
plots. For data plots, errorbars is like points, except that a vertical or
horizontal error bar is also drawn: for each point (x,y), a line is drawn
from (x,ylow) to (x,yhigh) or (xlow,y) to (xhigh,y). A tic mark is placed
at the ends of the error bar. The (ylow, yhigh) or (xlow,xhigh) values are
read from the data file's columns, as specified with the using option to
plot. See plot errorbars for more information.

The boxes style is only relevant to 2-d plotting. Another style called
boxerrorbars is also available and is only relevant to 2-d data file
plotting. This style is a combination of the boxes and errorbars styles.
The boxes style draws a box centred about the given x coordinate from the
yaxis to the given y coordinate. The width of the box is obtained in one of
three ways. First, if a data file has a fifth column, this will be used to
set the width of the box. Columns 3 and 4 (for boxerrorbars) are necessary
but ignored in this instance. Secondly, if a width has been set using the
set boxwidth command, this will be used. Otherwise the width of each box
will be calculated automatically so that it touches the adjacent boxes.

The boxes style is only relevant to 2-d plotting. It draws a box centred
about the given x coordinate from the yaxis to the given y coordinate. The
width of the box is obtained in one of three ways. If a data file has a
third column, this will be used to set the width of the box. Otherwise, if
a width has been set using the set boxwidth command, this will be used.
Otherwise the width of each box will be calculated automatically so that it
touches the adjacent boxes. Another style called boxerrorbars is also
available and is only relevant to 2-d data file plotting. This style is a
combination of the boxes and errorbars styles. The boxwidth will come from
the fourth column if the y errors are in the form of "ydelta" and the
boxwidth was not previously set equal to -2.0 (set boxwidth -2.0) or from
the fifth column if the y errors are in the form of "ylow yhigh". The
boxwidth = -2.0 is for the special case of 4-column data and the y errors
are in the form of "ylow yhigh". The boxwidth will be calculated
automatically so that each box touches the adjacent boxes. The width will
also be automatically calculated if 3-column data is used. The
boxxyerrorbars style is like the xyerrorbars option except that a box with
width (xhigh-xlow) and height (yhigh-ylow) is drawn instead of a cross of
that size.

For 2-d data with more than two columns, gnuplot will be picky about the
allowed plot styles. For three columns only xerrorbars, boxes, errorbars
(or yerrorbars), and boxerrorbars are allowed. If another plot style is
used, the style will be changed to yerrorbars. The boxerrorbars style will
calculate the boxwidth automatically. For four columns only xerrorbars,
xyerrorbars, boxxyerrorbars, boxerrorbars, and errorbars (or yerrorbars)
are allowed. An illegal plot style will be changed to yerrorbars. Five
column data allows only the boxerrorbars style. An illegal style will be
changed to boxerrorbars before plotting. Six and seven column data only
allows the xyerrorbars and boxxyerrorbars styles. Illegal styles will be
changed to xyerrorbars before plotting. Use the using option for plot to
setup the correct number of columns for the style you want.

The steps and fsteps styles is only relevant to 2-d plotting. The steps
style connects consecutive points with two line segments: the first from
(x1,y1) to (x2,y1) and the second from (x2,y1) to (x2,y2). The fsteps:
(x1,y1) to (x1,y2) and (x1,y2) to (x2,y2). Steps Demo.

Default styles are chosen with the set function style and set data style
commands.

By default, each function and data file will use a different line type and
point type, up to the maximum number of available types. All terminal
drivers support at least six different point types, and re-use them, in
order, if more than six are required. The LaTeX driver supplies an
additional six point types (all variants of a circle), and thus will only
repeat after twelve curves are plotted with points.

If desired, the style and (optionally) the line type and point type used
for a curve can be specified.

Syntax:

        with <style> {<linetype> {<pointtype>}}

where <style> is either lines, points, linespoints, impulses, dots, steps,
fstepsm {x,y,xy}errorbars, boxes, boxerrorbars, or boxxyerrorbars. The
<linetype> and <pointtype> are positive integer constants or expressions
and specify the line type and point type to be used for the plot. Line type
1 is the first line type used by default, line type 2 is the second line
type used by default, etc.

Examples:

This plots sin(x) with impulses:

        plot sin(x) with impulses

This plots x*y with points, x**2 + y**2 default:

        splot x*y w points, x**2 + y**2

This plots tan(x) with the default function style, "data.1" with lines:

        plot [ ] [-2:5] tan(x), "data.1" with l

This plots "leastsq.dat" with impulses:

        plot 'leastsq.dat' w i

This plots the data file 'population' with boxes:

        plot "population" with boxes

This plots "exper.dat" with errorbars and lines connecting the points:

        plot 'exper.dat' w lines, 'exper.dat' w errorbars

Here 'exper.dat' should have three or four data columns.

This plots x**2 + y**2 and x**2 - y**2 with the same line type:

        splot x**2 + y**2 with line 1, x**2 - y**2 with line 1

This plots sin(x) and cos(x) with linespoints, using the same line type but
different point types:

        plot sin(x) with linesp 1 3, cos(x) with linesp 1 4

This plots file "data" with points style 3:

        plot "data" with points 1 3

Note that the line style must be specified when specifying the point style,
even when it is irrelevant. Here the line style is 1 and the point style is
3, and the line style is irrelevant.

See set style to change the default styles.

---------------------------------------------------------------------------

title

A title of each plot appears in the key. By default the title is the
function or file name as it appears on the plot command line. The title can
be changed by using the title option. This option should precede any with
option.

Syntax:

        title "<title>"

where <title> is the new title of the plot and must be enclosed in quotes.
The quotes will not be shown in the key. Special characters may be given as
backslash and their octal value (\345), \t is anderstood.

Examples:

This plots y=x with the title 'x':

        plot x

This plots the "glass.dat" file with the title 'surface of revolution':

        splot "glass.dat" title 'surface of revolution'

This plots x squared with title "x^2" and "data.1" with title 'measured
data':

        plot x**2 title "x^2", "data.1" t 'measured data'

The title can be omitted from the key with the "notitle" option for plot
and splot. This can be useful when some curves are plotted solely for
decoration; for example, if one wanted a circular border for a polar plot,
he could say:

Example:

       set polar
       plot my_function(x), 1 notitle

This would generate a key entry for "my_function" but not for "1". See the
poldat.dem example.

---------------------------------------------------------------------------

print

The print command prints the value of <expression> to the screen.

Syntax:

        print <expression>

See expressions.

---------------------------------------------------------------------------

pwd

The pwd command prints the name of the working directory to the screen.

Syntax:

        pwd

---------------------------------------------------------------------------

quit

The exit and quit commands and END-OF-FILE character will exit GNUPLOT. All
these commands will clear the output device (as the clear command does)
before exiting.

---------------------------------------------------------------------------

replot

The replot command without arguments repeats the last plot or splot
command. This can be useful for viewing a plot with different set options,
or when generating the same plot for several devices.

Arguments specified after a replot command will be added onto the last plot
(splot) command (with an implied ',' separator) before it is repeated.
replot accepts the same arguments as the plot (splot) commands except that
ranges cannot be specified. See command line-editing for ways to edit the
last plot (splot) command.

---------------------------------------------------------------------------

reread

The reread command causes the current gnuplot command file, as specified by
a load command or on the command line, to be reset to its starting point
before further commands are read from it. This essentially implements an
endless loop of the commands from the beginning of the command file to the
reread command. The reread command has no effect if input from standard
input. Reread Animation

---------------------------------------------------------------------------

reset

The reset command causes all options that can be set with the set-command
to take on their default values. The only exceptions are that the terminal
set with set term and the output file set with set output are left
unchanged. This command is useful e.g. to restore the default settings at
the end of a command file, or to return to a defined state after lots of
settings have been changed within a command file. Please refer to the set
command to see the default values that the respective options take.

---------------------------------------------------------------------------

save

The save command saves user-defined functions, variables, set options or
all three plus the last plot (splot) command to the specified file.

Syntax:

        save  {<option>} "<filename>"

where <option> is functions, variables or set. If no option is used,
GNUPLOT saves functions, variables, set options and the last plot (splot)
command.

saved files are written in text format and may be read by the load command.

The filename must be enclosed in quotes.

Examples:

        save "work.gnu"
        save functions 'func.dat'
        save var 'var.dat'
        save set "options.dat"

---------------------------------------------------------------------------

set-show

The set command sets LOTS of options.

The show command shows their settings. show all shows all the settings.

angles
arrow
autoscale
border
boxwidth
clabel
clip
cntrparam
contour
data style
dgrid3d
dummy
format
function style
functions
grid
hidden3d
isosamples
key
keytitle
label
logscale
mapping
offsets
output
parametric
pointsize
polar
rrange
samples
size
style
surface
terminal
tics
time
timefmt
title
trange
urange
variables
view
vrange
xdata
xlabel
xmargin
xrange
xtics
mxtics
mytics
xdtics
xmtics
xzeroaxis
ydata
ylabel
yrange
ytics
ydtics
ymtics
yzeroaxis
zdata
zero
zeroaxis
zlabel
zrange
ztics
zdtics
zmtics

---------------------------------------------------------------------------

angles

By default, GNUPLOT assumes the independent variable in polar plots is in
units of radians. If set angles degrees is specified before set polar then
the default range is [0:360] and the independent variable has units of
degrees. This is particularly useful for plots of data files. The angle
setting also hold for the 3-d mapping as set via the set mapping command.

Syntax:

        set angles { degrees | radians }
        show angles

---------------------------------------------------------------------------

arrow

Arbitrary arrows can be placed on a plot using the set arrow command.

Syntax:

         set arrow {<tag>} {from <sx>,<sy>{,<sz>}}
                           {to <ex>,<ey>{,<ez>}} {{no}head}
         set noarrow {<tag>}
         show arrow

Unspecified coordinates default to 0. The x, y, and z values are in the
graph's coordinate system. The z coordinate is only used in splot commands.
<tag> is an integer that identifies the arrow. If no tag is given, the
lowest unused tag value is assigned automatically. The tag can be used to
delete or change a specific arrow. To change any attribute of an existing
arrow, use the set arrow command with the appropriate tag, and specify the
parts of the arrow to be changed. Specifying nohead requests the arrow be
drawn without a head (yielding a line segment). By default, arrows have
heads.

Arrows outside the plotted boundaries are permitted but may cause device
errors.

Examples:

To set an arrow pointing from the origin to (1,2), use:

         set arrow to 1,2

To set an arrow from (-10,4,2) to (-5,5,3), and tag the arrow number 3,
use:

         set arrow 3 from -10,4,2 to -5,5,3

To change the preceding arrow begin at 1,1,1, without an arrow head, use:

         set arrow 3 from 1,1,1 nohead

To delete arrow number 2 use:

         set noarrow 2

To delete all arrows use:

         set noarrow

To show all arrows (in tag order) use:

         show arrow

---------------------------------------------------------------------------

autoscale

Auto scaling may be set individually on the x, y or z axis or globally on
all axes. The default is to autoscale all axes.

When autoscaling, the plot range is automatically computed and the
dependent axis (y for a plot and z for splot) is scaled to include the
range of the function or data being plotted.

If autoscaling of the dependent axis (y or z) is not set, the current y or
z range is used.

See set yrange or set zrange.

Autoscaling the independent variables (x for plot and x,y for splot) is a
request to set the domain to match any data file being plotted. If there
are no data files then autoscaling an independent variable has no effect.
In other words, in the absence of a data file, functions alone do not
affect the x range (or the y range if plotting z = f(x,y)).

See set xrange, or set yrange.

The behavior of autoscaling remains consistent in parametric mode, however,
there are more dependent variables and hence more control over x, y, and z
plot scales. In parametric mode, the independent or dummy variable is t for
plots and u,v for splots. Autoscale in parametric mode, then, controls all
ranges (t, u, v, x, y, and z) and allows x, y, and z to be fully
autoscaled.

See set parametric.

Syntax:

        set autoscale <axes>
        set noautoscale <axes>
        show autoscale

where <axes> is either x, y, z or xy. If <axes> is not given then all axes
are assumed.

Examples:

This sets autoscaling of the y axis. x axis autoscaling is not affected.

        set autoscale y

This sets autoscaling of the x and y axes.

        set autoscale xy

This sets autoscaling of the x, y and z axes.

        set autoscale

This disables autoscaling of the x, y and z axes.

        set noautoscale

This disables autoscaling of the z axis only.

        set noautoscale z

parametric mode

---------------------------------------------------------------------------

parametric mode

When in parametric mode (set parametric) the xrange is as fully scalable as
the yrange. In other words, in parametric mode the x axis can be
automatically scaled to fit the range of the parametric function that is
being plotted. Of course, the y axis can also be automatically scaled just
as in the non-parametric case. If autoscaling on the x axis is not set, the
current x range is used.

When there is a mix of data files and functions, the xrange of the
functions is selected as that of the data files if autoscale is true for x.
While this keeps the behavior compatible with non-parametric plotting, it
may not be retained in the future. The problem is that, in parametric mode,
the x and y ranges are not as distinguishable as in the non-parametric mode
and this behavior may not be the most useful.

For completeness a last command set autoscale t is accepted. However, the
effect of this "scaling" is very minor. When GNUPLOT determines that the t
range would be empty it makes a small adjustment if autoscaling is true.
Otherwise, GNUPLOT gives an error. Such behavior may, in fact, not be very
useful and the command set autoscale t is certainly questionable.

splot extends the above idea similarly. If autoscaling is set then x, y,
and z ranges are computed and each axis scaled to fit the resulting data.

---------------------------------------------------------------------------

border

The set border and set noborder commands controls the display of the plot
borders for the plot commands. The borders are encoded in a four bit
integer:

       SOUTH    0th bit
       WEST    1st bit
       NORTH   2nd bit
       EAST    3rd bit

To facilitate two y-scales, the tic marks and labels will only be written
to the EAST and NORTH borders if the opposite border is off.

Syntax:

        set border    (turns on all borders)
        set border 3  (only SOUTHWEST borders)
        set border 12 (only NORTHEAST borders with tics on top and right)
        set noborder
        show border

e.g Borders Demo.

---------------------------------------------------------------------------

boxwidth

The set boxwidth command is used to set the default width of boxes in the
boxes and boxerrorbars styles.

If a data file is plotted without the width being specified in the third to
fifth columns, or a function is plotted, the width of each box is set by
the set boxwidth command. If a width is given after the set boxwidth
command then this is used as the width. Otherwise the width of each box
will be calculated automatically so that it touches the adjacent boxes.
Four-column data may have the width be calculated automatically if the
width is first set to -2.0. Otherwise, the fourth column will be
interpreted as the box width. See boxerrorbars or set style for more
details.

Syntax:

         set boxwidth {<width>}
         show boxwidth

To set the box width to automatic use the command

         set boxwidth
         set boxwidth -2  (4-col data)

---------------------------------------------------------------------------

clabel

GNUPLOT will vary the linetype used for each contour level when clabel is
set. When this option on (the default), a legend labels each linestyle with
the z level it represents.

Syntax:

        set clabel
        set noclabel
        show clabel

---------------------------------------------------------------------------

clip

GNUPLOT can clip data points and lines that are near the boundaries of a
plot.

Syntax:

        set clip <clip-type>
        set noclip <clip-type>
        show clip

Three clip types are supported by GNUPLOT: points, one, and two. One, two,
or all three clip types may be active for a single plot.

The points clip type forces GNUPLOT to clip (actually, not plot at all)
data points that fall within but too close to the boundaries (this is so
the large symbols used for points will not extend outside the boundary
lines). Without clipping points near the boundaries may look bad; try
adjusting the x and y ranges.

Setting the one clip type causes GNUPLOT to plot the line segments which
have only one of the two endpoints within the plotting region. Only the
in-range portion of the line is drawn. The alternative is to not draw any
portion of the line segment.

Some lines may have both endpoints out of range, but pass through the
plotting area. Setting the two clip-type allows the visible portion of
these lines to be drawn.

In no case is a line drawn outside the plotting area.

The defaults are noclip points, clip one, and noclip two.

To check the state of all forms of clipping, use

        show clip

For backward compatibility with older versions, the following forms are
also permitted.

       set clip
       set noclip

set clip is synonymous with set clip points. set noclip turns off all three
types of clipping.

---------------------------------------------------------------------------

cntrparam

Sets the different parameters for the contouring plot (see also contour).

Syntax:

 set cntrparam { { linear | cubicspline | bspline } |
    points <n> |
    order <n>  |
    levels { [ auto ] <n> |
    discrete <z1>,<z2>, ... |
    incremental {<start>, <incr>{, <end>} } }

Examples:

    set cntrparam bspline
    set cntrparam points 7
    set cntrparam order 10
    set cntrparam levels auto 5                   # 5 automatic levels
    set cntrparam levels discrete .1,1/exp(1),.9  # 3 discrete at .1,.37,.9
    set cntrparam levels incremental  0,.1,.4
    # 5 incremental levels at 0, .1, .2, .3 and .4
    set cntrparam levels 10
    # sets n = 10 retaining current setting of auto, discr. and
    # increment's start and increment value, while changing end
    set cntrparam levels incremental 100,50
    # set start = 100 and increment = 50, retaining n levels

This command controls the way contours are plotted. <n> should be an
integral constant expression and <z1>, <z2> any constant expressions. The
parameters are:

linear, cubicspline, bspline - Controls type of approximation or
interpolation. If linear, then the contours are drawn piecewise linear, as
extracted from the surface directly. If cubicspline, then piecewise linear
contours are interpolated to form a somewhat smoother contours, but which
may undulate. The third option is the uniform bspline, which only
approximates the piecewise linear data but is guaranteed to be smoother.

points - Eventually all drawings are done with piecewise linear strokes.
This number controls the number of points used to approximate a curve.
Relevant for cubicspline and bspline modes only.

order - Order of the bspline approximation to be used. The bigger this
order is, the smoother the resulting contour. (Of course, higher order
bspline curves will move further away from the original piecewise linear
data.) This option is relevant for bspline mode only. Allowed values are
integers in the range from 2 (linear) to 10.

levels - Number of contour levels, 'n'. Selection of the levels is
controlled by 'auto' (default), 'discrete', and 'incremental'. For 'auto',
if the surface is bounded by zmin and zmax then contours will be generated
from zmin+dz to zmax-dz in steps of size dz, where dz = (zmax - zmin) /
(levels + 1). For 'discrete', contours will be generated at z = z1, z2 ...
as specified. The number of discrete levels is limited to
MAX_DISCRETE_LEVELS, defined in plot.h to be 30. If 'incremental', contours
are generated at <n> values of z beginning at <start> and increasing by
<increment>. Contours Demo and contours with User Defined Levels.

---------------------------------------------------------------------------

contour

Enable contour drawing for surfaces. This option is available for splot
only.

Syntax:

        set contour { base | surface | both }
        set nocontour

If no option is provided to set contour, the default is base. The three
options specify where to draw the contours: base draws the contours on the
grid base where the x/ytics are placed, surface draws the contours on the
surfaces themselves, and both draws the contours on both the base and the
surface.

See also set cntrparam for the parameters that affect the drawing of
contours. Contours Demo and contours with User Defined Levels.

---------------------------------------------------------------------------

data style

The set data style command changes the default plotting style for data
plots.

Syntax:

        set data style
        show data style
        set data style <style-choice>

In the first case, set data style returns the possible style choices:
lines, points, linespoints, dots, steps, impulses, {x,y,xy}errorbars,
boxes, boxerrorbars or boxxyerrorbars. show data style shows the current
default plotting style for data. set data style dots would actually change
the default plotting style. See also plot.

---------------------------------------------------------------------------

dgrid3d

Enables and sets the different parameters for non grid to grid data
mapping.

Syntax:

        set dgrid3d {,{<row_size>}{,{<col_size>}{,<norm>}}}
        set nodgrid3d

Examples:

       set dgrid3d 10,10,2
       set dgrid3d ,,4

The first selects a grid of size 10 by 10 to be constructed and the use of
L2 norm in the distance computation. The second only modifies the norm to
be used to L4.

By default this option is disabled. When enabled, 3d data read from a file
is always treaded as a scattered data set. A grid with dimensions derived
from a bounding box of the scattered data and size as specified by the
row/col_size above is created for plotting and contouring. The grid is
equally spaced in x and y while the z value is computed as a weighted
average of the scattered points distance to the grid points. The closer the
scatter points to a grid point are the more effect they have on that grid
point. The third, norm, parameter controls the "meaning" of the distance,
by specifying the distance norm. This distance computation is optimized for
powers of 2 norms, specifically 1, 2, 4, 8, and 16, but any nonnegative
integer can be used.

This dgrid3d option is a simple low pass filter that converts scattered
data to a grid data set. More sophisticated approaches to this problem
exists and should be used as a preprocess to and outside gnuplot if this
simple solution is found inadequate. Dgrid3d Demo.

---------------------------------------------------------------------------

dummy

By default, GNUPLOT assumes that the independent variable for the plot
command is x, and the independent variables for the splot command are x and
y. They are called the dummy variables because it is just a notation to
indicate the independent variables. The set dummy command changes these
default dummy variable names. For example, it may be more convenient to
call the dummy variable t when plotting time functions:

        set dummy t
        plot sin(t), cos(t)

Syntax:

        set dummy <dummy-var>{,<dummy-var>}
        show dummy

Examples:

        set dummy u,v
        set dummy ,s

to set both dummy variables to u and v or set only the second variable to
s.

The set parametric command also changes the dummy variables (to t for plot
and u,v for splots).

---------------------------------------------------------------------------

format

The format of the tic-mark labels can be set with the set format command.
The default format for both axes is "%g", but other formats such as "%.2f"
or "%3.0fm" are often desirable. Anything accepted by printf when given a
double precision number, and then accepted by the terminal, will work. In
particular, the formats f, e, and g will work, and the d, o, x, c, s, and u
formats will not work. If data type for the axis is date/time, the format
string must contain valid codes for the strftime function (do: man
strftime). It's recommended to stick to the conversion codes accepted by
the set timefmt command. If the format string looks like a floating point
format, then gnuplot tries to construct a reasonable format.

Syntax:

        set format {<axes>} {"<format-string>"}
        show format

where <axes> is either x, y, z, xy, or nothing (which is the same as xy).
The length of the string representing a ticmark (after formatting with
printf) is restricted to 100 characters. If the format string is omitted,
the format will be returned to the default "%g". For LaTeX users, the
format "$%g$" is often desirable. If the empty string "" is used, no label
will be plotted with each tic, though the tic mark will still be plotted.
To eliminate all tic marks, use set noxtics or set noytics.

For plot newlines (\n) is accepted in the xaxis format string, and for
splot newlines is allowed for both x- and yaxis format strings.

See also set xtics and set ytics for more control over tic labels.

---------------------------------------------------------------------------

function style

The set function style command changes the default plotting style for
functions.

Syntax:

        set function style
        show function style
        set function style <style-choice>

In the first case, set function style returns the possible style choices:
lines, points, linespoints, dots, steps, impulses, {x,y,xy}errorbars,
boxes, boxerrorbars, or boxxyerrorbars. show function style shows the
current default plotting style for functions. set function style
linespoints would actually change the default plotting style. See also
plot.

---------------------------------------------------------------------------

functions

The show functions command lists all user-defined functions and their
definitions.

Syntax:

        show functions

e.g. Splines as User Defined Functions. and Use of functions and complex
variables for airfoils

---------------------------------------------------------------------------

grid

The optional set grid draws a grid at the major tic marks with the axis
linetype. The grid can include the minor tic marks by set grid mxtics
and/or set grid mytics. The default is no grid on the minor tic marks.

Syntax:

        set grid {mxtics OR mytics}
        set nogrid
        show grid

---------------------------------------------------------------------------

hidden3d

The set hidden3d command enables hidden line removal for explicit surface
plotting (see splot). Hidden line removal may be used for both explicit
functions and for explicit data. It now works for parametric surfaces as
well.

When this flag is set both the surface hidden portion and possibly its
hidden contours (see set contour) as well as the hidden grid will be
removed. Labels and arrows are always visible and are unaffected by this
command.

Each surface has its hidden parts removed with respect to itself and to
other surfaces, if more than one surface is plotted. This mode is
meaningful when surfaces are plotted using line style drawing only.

Syntax:

        set hidden3d
        set nohidden3d
        show hidden3d

e.g. Hidden Line Removal Demo and Complex Hidden Line Demo.

---------------------------------------------------------------------------

isosamples

An isoline is a curve parametrized by one of the surface parameters while
the other surface parameter is fixed. Isolines are a simple means to
display a surface. By fixing the u parameter of surface s(u,v), the iso-u
lines of the form c(v) = s(u0,v) are produced, and by fixing the v
parameter, the iso-v lines of the form c(u) = s(u,v0) are produced.

The isoline density of surfaces may be changed by the set isosamples
command. By default, sampling is set to 10 isolines per u or v axis. A
higher sampling rate will produce more accurate plots, but will take
longer. This parameter has no effect on data file plotting.

Syntax:

        set isosamples <iso_1> {,<iso_2>}
        show isosamples

Each surface plot will have <iso_1> iso-u lines and <iso_2> iso-v lines. If
you only specify <iso_1>, <iso_2> will be set to the same value as <iso_1>.

When a surface plot is being done without the removal of hidden lines, set
samples also has an effect on the number of points being evaluated. See set
samples.

---------------------------------------------------------------------------

key

The set key enables a key describing curves on a plot. By default the key
is placed in the upper right corner of the plot. The keywords left, right,
top, bottom, outside and below is provided to place the keys in the other
corners inside the plot or to the right (outside) or below the plot. They
may be given alone or combined. Justification of the key label is controled
by Left or Right. The default is Right.

Syntax:

        set key
        set key <x>,<y>{,<z>}
        set key <keyword> {<keyword> {<justification>}}
        set nokey
        show key

The coordinates <x>, <y> (and <z> for splots) specify the location of the
key on the plot. The key is drawn as a sequence of lines, with one plot
described on each line. On the right hand side of each line is a
representation that attempts to mimic the way the curve is plotted. On the
left side of each line is the text description, obtained from the plot
command. See plot title to change this description. The lines are
vertically arranged so an imaginary straight line divides the left- and
right-hand sides of the key. It is the coordinates of this line that are
specified with the set key command. In a plot, only the x and y coordinates
are used to specify the line position. For a splot, x, y and z are all
being used as a 3-d location mapped using the same mapping as the plot
itself to form the required 2-d screen position of the imaginary line.

Some or all of the key may be outside of the plot boundary, although this
may interfere with other labels and may cause an error on some devices. If
you use the keywords outside or below, gnuplot makes space for the keys and
the plot becomes smaller. Putting keys outside to the right, they occupy as
few colums as possible, and putting them below, as many culumns as possible
(depending of the length of the labels). Thus stealing as little space from
the plot as possible.

Examples:

This places the key at the default location:

        set key

This disables the key:

        set nokey

This places a key at coordinates 2,3.5,2

        set key 2,3.5,2

Put the keys below the plot

        set key below

Place the beys in the bottom left corner and justify the text left:

        set key left bottom Left

Put it in the default corner:

        set key

---------------------------------------------------------------------------

keytitle

This command allows a key header to the printed above the keys.

Syntax:

        set keytitle "<string>"

---------------------------------------------------------------------------

label

Arbitrary labels can be placed on the plot using the set label command. If
the z coordinate is given on a plot it is ignored; if it is missing on a
splot it is assumed to be 0. The strings is scanned for backslash-octal
(\nnn) conversion.

Syntax:

         set label {<tag>} {"<label_text>"} {at <x>,<y>{,<z>}}
                           {<justification>}
         set nolabel {<tag>}
         show label

The text defaults to "", and the position to 0,0,0. The <x>, <y>, and <z>
values are in the graph's coordinate system. The tag is an integer that is
used to identify the label. If no <tag> is given, the lowest unused tag
value is assigned automatically. The tag can be used to delete or change a
specific label. To change any attribute of an existing label, use the set
label command with the appropriate tag, and specify the parts of the label
to be changed.

By default, the text is placed flush left against the point x,y,z. To
adjust the way the label is positioned with respect to the point x,y,z, add
the parameter <justification>, which may be left, right or center,
indicating that the point is to be at the left, right or center of the
text. Labels outside the plotted boundaries are permitted but may interfere
with axes labels or other text.

If one (or more) axis is timeseries, the coordiate should be given as a
quoted time string according to the timefmt-format string. See set
{x,y,z}data and set timefmt.

Examples:

To set a label at (1,2) to "y=x" use:

         set label "y=x" at 1,2

To set a label "y=x^2" with the right of the text at (2,3,4), and tag the
label number 3, use:

         set label 3 "y=x^2" at 2,3,4 right

To change the preceding label to center justification, use:

         set label 3 center

To delete label number 2 use:

         set nolabel 2

To delete all labels use:

         set nolabel

To show all labels (in tag order) use:

         show label

Timeseries (timefmt="%d/%m/%y,%H:%M):

         set label "Harvest" at "25/8/93",1

(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)

---------------------------------------------------------------------------

logscale

Log scaling may be set on the x, y, and z axes.

Syntax:

        set logscale <axes> <base>
        set nologscale <axes>
        show logscale

where <axes> may be any combinations of x, y, and z, in any order, and
where <base> is the base of the log scaling. If <base> is not given, then
10 is assumed. If <axes> is not given then all three axes are assumed. The
command set logscale turns on log scaling on the specified axes, while set
nologscale turns off log scaling.

Examples:

To enable log scaling in both x and z axes:

       set logscale xz

To enable scaling log base 2 of the y axis:

       set logscale y 2

To disable z axis log scaling:

       set nologscale z

---------------------------------------------------------------------------

mapping

Syntax:

        set mapping { cartesian | spherical | cylindrical }

Data for splots are usually in regular Euclidean space and are provided in
Cartesian coordinates. Such 3-d data require three coordinates (x, y and z)
or one coordinate (only z) in each line in the data file. In order to be
able to use spherical or cylindrical coordinate systems, use the set
mapping command. In both cases two coordinates are expected in each line of
the data. For a spherical coordinate system, these are theta and phi (in
units as specified by set angles) and the mapping is:

        x = cos( theta ) * cos( phi )
        y = sin( theta ) * cos( phi )
        z = sin( phi )

For a cylindrical coordinate system, the mapping uses two variables, theta
(in units as specified by set angles) and z:

        x = cos( theta )
        y = sin( theta )
        z = z

Again, note that mapping will affect data file splots only. Mapping Demos.

---------------------------------------------------------------------------

offsets

The amount of the graph that the plot takes up may be controlled to some
extent with the set offsets command. This command takes four offset
arguments: <left>, <right>, <top> and <bottom>. By default, each offset is
0. Each offset may be a constant or an expression. Left and right offsets
are given in units of the x axis, while top and bottom offsets are given in
units of the y axis. The plot of sin(x), displayed with offsets of 0, 0, 2,
2 will take up 1/3 of the displayed y axis. Offsets are particularly useful
with polar coordinates as a means of compensating for aspect ratio
distortion. Offsets are ignored in splots.

Syntax:

        set offsets <left>, <right>, <top>, <bottom>
        show offsets

---------------------------------------------------------------------------

output

By default, plots are displayed to the standard output. The set output
command redirects the display to the specified file or device.

Syntax:

        set output {"<filename>"}
        show output

The filename must be enclosed in quotes. If the filename is omitted, output
will be sent to the standard output.

On machines with popen functions (UNIX), output can be piped through a
shell command if the first letter of the filename is '|'. For instance,

Syntax:

        set output "|lpr -Plaser filename"
        set output "|lp -dlaser filename"

(On MSDOS machines, set output "prn" will direct the output to the default
printer.)

---------------------------------------------------------------------------

parametric

The set parametric command changes the meaning of plot (splot) from normal
functions to parametric functions. The command set noparametric changes the
plotting style back to normal, single-valued expression plotting.

In 2-d plotting, a parametric function is determined by a pair of
parametric functions operating on a parameter. An example of a 2-d
parametric function would be plot sin(t),cos(t) (which defines a circle).

For 3-d plotting, the surface is described as x=f(u,v), y=g(u,v), z=h(u,v).
Therefore a triplet of functions are required. An example of 3-d parametric
function would be cos(u)*cos(v),cos(u)*sin(v),sin(u) (which defines a
sphere). It takes three parametric function specifications in terms of the
parametric dummy arguments to describe a single graph.

The total set of possible plots is a superset of the simple f(x) style
plots, since the two (three) functions can describe the x and y (and z)
values to be computed separately. In fact, plots of the type t,f(t)
(u,v,f(u,v)) are equivalent to those produced with f(x) when the x values
are computed using the identity function as the first function.

Note that the order the parametric functions are specified is xfunction,
yfunction (and zfunction) and that each operates over the common parametric
domain.

Also, the set parametric function implies a new range of values. Whereas
the normal f(x) and f(x,y) style plotting assume an xrange and yrange (and
zrange), the parametric mode additionally specifies a trange, urange, and
vrange. These ranges may be set directly with set trange, set urange and
set vrange, or by specifying the range on the plot or splot commands.
Currently the default range for these parametric variables is [-5:5].
Setting the ranges to something more meaningful is expected.

---------------------------------------------------------------------------

pointsize

The set pointsize command changes the size of the points used in plots.
Default is pointsize 1.0. Larger pointsizes (>1.0) are usefull for high
resolution in bitmapped graphics.

Please note that the pointsize setting is not supported with all terminal
types.

---------------------------------------------------------------------------

polar

The set polar command changes the meaning of the plot from rectangular
coordinates to polar coordinates. In polar coordinates, the dummy variable
(x) is an angle. The range of this angle is changed from whatever it was to
[0:2*pi], or, if degree unit has been selected, to [0:360] (see set
angles).

The command set nopolar changes the meaning of the plot back to the default
rectangular coordinate system. The range of x is changed from whatever it
was to [-10:10].

The set polar command is not supported for splots. See the set mapping
command for similar functionality for splots.

While in polar coordinates the meaning of an expression in x is really r =
f(x), where x is an angle of rotation. The xrange controls the domain (the
angle) of the function, and the yrange controls the range (the radius). The
plot is plotted in a rectangular box, and the x and y axes are both in
units of the radius. Thus, the yrange controls both dimensions of the plot
output. The tics and units are written along the axes rather than at the
left and bottom. These unit are offset by <rmin> specified by the rrange
(See set rrange). It is not possible to specify different output dimensions
in the x or y directions. The yrange can be used to shift the plot
diagonally to display only the first or third quadrants.

Syntax:

        set polar
        set nopolar
        show polar

Example:

        set polar
        plot x*sin(x)
        plot [-2*pi:2*pi] [-3:3] x*sin(x)

The first plot uses the default polar angular domain of 0 to 2*pi. The
radius (and the size of the plot) is scaled automatically. The second plot
expands the domain, and restricts the range of the radius (and the size of
the plot) to [-3:3]. Polar demos Polar Data Plot.

---------------------------------------------------------------------------

rrange

The set rrange command sets the radial range used to compute x and y values
when in polar mode. If not in polar mode (see set polar) then this range is
not used. Use of this command offsets the polar singularity to the <rmin>
value and shifts the units on the axes tic marks. For instance, set rrange
[-40:40] would set the origin to -40 and would plot values of radial values
between -40 to 40. Thus, if 360 degrees of data were plotted, then the plot
would extend 80 units in radially from the origin. To view the entire plot,
a set yrange [-80:80] command would create a square viewport with a
circular plot tangent at the axes. Because xrange is used specify the
angular extent, only a square viewport can be specified by yrange. For
instance, set yrange [0:80] would display the first quadrant and set yrange
[-80:0] would display the third quadrant. Any square viewport of any size
can be specified but it is constrained to be centered on a 45 degree line.

This range may also be specified on the plot command line when in polar
mode.

Syntax:

        set rrange [{<rmin> : <rmax>}]

where <rmin> and <rmax> terms are constants or expressions.

Both the <rmin> and <rmax> terms are optional. Anything omitted will not be
changed, so

        set rrange [:10]

changes rmax to 10 without affecting rmin.

---------------------------------------------------------------------------

samples

The sampling rate of functions may be changed by the set samples command.
By default, sampling is set to 100 points. A higher sampling rate will
produce more accurate plots, but will take longer. This parameter no longer
has any effect on data-file plotting.

Syntax:

        set samples <samples_1> {,<samples_2>}
        show samples

When a 2-d plot is being done, only the value of <samples_1> is relevant.

When a surface plot is being done without the removal of hidden lines, the
value of samples specifies the number of samples that are evaluated per iso
line. Each iso-v line will have <sample_1> samples and each iso-u line will
have <sample_2> samples. If you only specify <samples_1>, <samples_2> will
be set to the same value as <samples_1>. See also set isosamples.

---------------------------------------------------------------------------

size

The set size command scales the displayed size of the plot. On some
terminals, changing the size of the plot will result in text being
misplaced. Increasing the size of the plot may produce strange results.
Decreasing is safer.

Syntax:

        set size {<xscale>,<yscale>}
        show size

The <xscale> and <yscale> values are the scaling factors for the size. The
defaults (1,1) are selected if the scaling factors are omitted.

Examples:

To set the size to normal size use:

        set size

To make the plot half size use:

        set size 0.5,0.5

To make a landscape plot have a 1:1 aspect ratio in polar mode use:

        set size 0.721,1.0

To show the size use:

        show size

For the LaTeX and Fig terminals the default size (scale factor 1,1) is 5
inches wide by 3 inches high. The big Fig terminal (bfig) is 7 inches wide
by 5 inches high. The postscript default is landscape mode 10 inches wide
and 7 inches high. Note that the size of the plot includes the space used
by the labels; the plotting area itself is smaller.

---------------------------------------------------------------------------

style

Plots may be displayed in one of thirteen styles: lines, points,
linespoints, impulses, dots, steps, fsteps, {x,y,xy}errorbars, boxes,
boxerrorbars, or boxxyerrorbars. The lines style connects adjacent points
with lines. The points style displays a small symbol at each point. The
linespoints style does both lines and points. The impulses style displays a
vertical line from the x axis (or from the grid base for splot) to each
point. The dots style plots a tiny dot at each point; this is useful for
scatter plots with many points.

The errorbars (or yerrorbars), xerrorbars, xyerrorbars styles are only
relevant to 2-d data file plotting. It is treated like points for splots
and function plots. For data plots, errorbars is like points, except that a
vertical or horizontal error bar is also drawn: for each point (x,y), a
line is drawn from (x,ylow) to (x,yhigh) or (xlow,y) to (xhigh,y). A tic
mark is placed at the ends of the error bar. The (ylow, yhigh) or
(xlow,xhigh) values are read from the data file's columns, as specified
with the using option to plot. See plot errorbars for more information.

The boxes style is only relevant to 2-d plotting. It draws a box centred
about the given x coordinate from the yaxis to the given y coordinate. The
width of the box is obtained in one of three ways. If a data file has a
third column, this will be used to set the width of the box. Otherwise, if
a width has been set using the set boxwidth command, this will be used.
Otherwise the width of each box will be calculated automatically so that it
touches the adjacent boxes. Another style called boxerrorbars is also
available and is only relevant to 2-d data file plotting. This style is a
combination of the boxes and errorbars styles. The boxwidth will come from
the fourth column if the y errors are in the form of "ydelta" and the
boxwidth was not previously set equal to -2.0 (set boxwidth -2.0) or from
the fifth column if the y errors are in the form of "ylow yhigh". The
boxwidth = -2.0 is for the special case of 4-column data and the y errors
are in the form of "ylow yhigh". The boxwidth will be calculated
automatically so that each box touches the adjacent boxes. The width will
also be automatically calculated if 3-column data is used. The
boxxyerrorbars style is like the xyerrorbars option except that a box with
width (xhigh-xlow) and height (yhigh-ylow) is drawn instead of a cross of
that size.

For 2-d data with more than two columns, gnuplot will be picky about the
allowed plot styles. For three columns only xerrorbars, boxes, errorbars
(or yerrorbars), and boxerrorbars are allowed. If another plot style is
used, the style will be changed to yerrorbars. The boxerrorbars style will
calculate the boxwidth automatically. For four columns only xerrorbars,
xyerrorbars, boxxyerrorbars, boxerrorbars, and errorbars (or yerrorbars)
are allowed. An illegal plot style will be changed to yerrorbars. Five
column data allows only the boxerrorbars style. An illegal style will be
changed to boxerrorbars before plotting. Six and seven column data only
allows the xyerrorbars and boxxyerrorbars styles. Illegal styles will be
changed to xyerrorbars before plotting. Use the using option for plot to
setup the correct number of columns for the style you want.

The steps and fsteps styles is only relevant to 2-d plotting. The steps
style connects consecutive points with two line segments: the first from
(x1,y1) to (x2,y1) and the second from (x2,y1) to (x2,y2). The fsteps:
(x1,y1) to (x1,y2) and (x1,y2) to (x2,y2).

Default styles are chosen with the set function style and set data style
commands. See plot style for information about how to override the default
plotting style for individual functions.

Syntax:

        set function style <style>
        set data style <style>
        show function style
        show data style

where <style> is lines, points, linespoints, impulses, dots, steps, fsteps,
{x,y,xy}errorbars, boxes, boxerrorbars, or boxxyerrorbars.

---------------------------------------------------------------------------

surface

set surface controls the display of surfaces. It is useful if contours are
to be displayed by themselves. Whenever set nosurface is issued, no surface
isolines/mesh will be drawn. See also set contour.

Syntax:

        set surface
        set nosurface
        show surface

---------------------------------------------------------------------------

terminal

GNUPLOT supports many different graphics devices. Use the set terminal
command to select the type of device for which GNUPLOT will produce output.

Syntax:

        set terminal {<terminal-type>}
        show terminal

If <terminal-type> is omitted, GNUPLOT will list the available terminal
types. <terminal-type> may be abbreviated.

Use set output to redirect this output to a file or device.

Several terminals have additional options. For example, see dumb, iris4d,
hpljii or postscript.

aifm
atari ST
dumb
epson
gpic
hpljii
latex
imagen
linux
iris4d
mf
mif
nec-cp6
pbm
pcl5
postscript
enhanced postscript
pslatex
fig
regis
table
uniplex
windows

---------------------------------------------------------------------------

aifm

Several options may be set in the Adobe Illustrator 3.0 driver.

Syntax:

        set terminal aifm {<color>}
                                {"<fontname>"} {<fontsize>}

Selecting default sets all options to their default values. <color> is
either color or monochrome. "<fontname>" is the name of a valid PostScript
font. <fontsize> is the size of the font in PostScript points, before
scaling by the set size command. Defaults are monochrome, "Helvetica", and
14pt.

Also, since AI does not really support multiple pages, multiple graphs will
be output directly on one another. However, each graph will be grouped
individually, making it easy to separate them inside AI (just pick them up
and move them).

Examples:

        set term aifm
        set term aifm 22
        set size 0.7,1.4
        set term aifm color "Times-Roman" 14

---------------------------------------------------------------------------

atari ST

The atari terminal has an option to set the character size and the screen
colors. The driver expects a space separated list the char size and maximal
16 3 digit hex numbers where each digit represents RED, GREEN and BLUE (in
that order). The range of 0-15 is scaled to whatever color range the screen
actually has. On a normal ST screen, odd and even intensities are the same.

Examples:

       set terminal atari 4 # (use small (6x6) font)
       set terminal atari 6 0 # (set monochrome screen to white on black)
       set terminal atari 13 0 fff f00 f0 f ff f0f ff0
       # (set first eight colors to black, white, green, blue, cyan, \
         purple, and yellow and use large font (8x16).)

Additionally, if an environment variable GNUCOLORS exists, its contents are
interpreted as an options string, but an explicit terminal option takes
precedence.

---------------------------------------------------------------------------

dumb

The dumb terminal driver has an optional size specification.

Syntax:

        set terminal dumb {<xsize> <ysize>}

where <xsize> and <ysize> set the size of the dumb terminals. Default is 79
by 24.

Examples:

        set term dumb
        set term dumb 79 49 # VGA screen--why would anyone want to do that?

---------------------------------------------------------------------------

epson

This set of drivers support Epson printers and derivatives. See also the
NEC driver. epson is a generic 9 wire printer with a resolution of 512x384.
starc is a Star Color printer with the same resolution. epson180 and
epson60 are 180 dpi and 60 dpi drivers for newer 24 wire printers. This
also includes bubble jet printers. Their resolutions are 1260x1080 and
480x360, respectively. The tandy60 is identical to the epson60 driver with
one additional escape sequence to start IBM mode. With all of these
drivers, a binary copy is required on a PC to print. Do not use print.

       copy file /b lpt1:

---------------------------------------------------------------------------

gpic

This driver is only known to work the Free Software Foundation gpic/groff
package. Modification for the Document Workbench pic/troff package would be
appreciated. FSF gpic can also produce TeX output.

A simple graph can be formatted using

     groff -p -mpic -Tps file.pic > file.ps.

The output from pic can be pipe-lined into eqn, so it is possible to put
complex functions in a graph with the set label and set {x/y}label
commands. For instance,

   set ylab '@space 0 int from 0 to x alpha ( t ) roman d t@'

Will label the y-axis with a nice integral if formatted with the command:

   gpic filename.pic | geqn -d@@ -Tps | groff -m[macro-package] -Tps
        > filename.ps

Figures made this way can be scaled to fit into a document. The pic
language is easy to understand, so the graphs can be edited by hand if need
be. All coordinates in the pic-file produced by gnuplot are given as
x+gnuplotx and y+gnuploty. By default x and y are given the value 0 If this
line is removed with an editor in a number of files one can put several
graphs i one figure like this (default size is 5.0x3.0 inches)

   .PS 8.0
   x=0;y=3
   copy "figa.pic"
   x=5;y=3
   copy "figb.pic"
   x=0;y=0
   copy "figc.pic"
   x=5;y=0
   copy "figd.pic"
   .PE

This will produce an 8 inches wide figure with four graphs in two rows on
top of each other

One can also achieve the same thing by the command

  set term pic x y

For example, using

  .PS 6.0
  copy "trig.pic"
  .PE

---------------------------------------------------------------------------

hpljii

The HP LaserJet II and HP DeskJet drivers have a single option.

Syntax:

        set terminal hpljii {<resolution>}
        set terminal hpdj   {<resolution>}

where <resolution> is the resolution of the output in dots per inch. It
must be 75, 100, 150 or 300. Note: there must be enough memory available to
rasterize at the higher resolutions.

Example:

        set terminal hpljii 150

---------------------------------------------------------------------------

latex

The LaTeX and EMTeX driver allows one to specify a font type and a font
size for the labels around a gnuplot graph.

Options are: Fonts:

      default          (Roman 10 point)
      courier
      roman

at any size you specify. (BEWARE METAFONT will not like odd sizes.) eg.

      gnuplot> set term latex courier 5

Unless your driver is capable of building fonts at any size (e.g. dvips),
stick to the standard 10, 11 and 12 point size.

---------------------------------------------------------------------------

imagen

The imagen driver is able to draw several plots on each page (in either
portrait or landscape orientation), and fontsize may also be specified.

Options are:

      portrait
      landscape        (default)
      [ x , y ]        (where x and y is number of plots in x- and y direction
                        on the page)
      n                (where n is fontsize in points)

To plot 6 plots pr page in two columns in portrait orientation:

      set term imagen po [2,3]

---------------------------------------------------------------------------

linux

The Linux driver has only a few options. You can select SVGA or a VGA
screen and force chipsets if the svgalib fails to detect your chipset. Both
arguments are optional. If no chipset is specifed, it is autodetected (this
option should really only be used if it is autodetected incorrectly). The
mode defaults to SVGA; if it is not available, it automatically drops to
VGA.

Syntax:

        set terminal linux {chipset} {mode}

Mode can be:

        VGA  - force 640x480x16 (useful for Tridents)
        SVGA - use 1024x768x256 (if available)
        S800 - use  800x600x256 (if available)
        S816 - use  800x600x16  (512k users, not available)

Currently the following chipsets can be used with svgalib (v0.5):

        TVGA8900
        ET4000
        CIRRUS
        OAK (?)

Other chipsets are supported to 640x480x16 as generic VGA.

The current svgalib (0.5) doesn't handle Trident cards very well, if your
screen is not restored properly, you will have to use the VGA option.

---------------------------------------------------------------------------

iris4d

The iris4d driver can operate in two modes.

Syntax:

        set terminal iris4d {24}

If the hardware supports only 8 bits, use the default set terminal iris4d.
If, however, the hardware supports 24 bits (8 per red/green/blue), use set
terminal iris4d 24.

When using 24-bit mode, the colors can be directly specified via the file
.gnuplot_iris4d that is searched in the current directory and then in the
home directory specified by the HOME environment variable. This file holds
RGB values for the background, border, labels and nine plotting colors, in
that order. For example, here is a file containing the default colors:

        85   85   85     /* Back Ground */
        0    0    0      /* Boundary */
        170  0    170    /* Labeling */
        85   255  255    /* Plot Color 1 */
        170  0    0      /* Plot Color 2 */
        0    170  0      /* Plot Color 3 */
        255  85   255    /* Plot Color 4 */
        255  255  85     /* Plot Color 5 */
        255  85   85     /* Plot Color 6 */
        85   255  85     /* Plot Color 7 */
        0    170  170    /* Plot Color 8 */
        170  170  0      /* Plot Color 9 */

This file has exactly 12 lines of RGB triples. No empty lines are allowed
and anything after the third number in line is ignored.

---------------------------------------------------------------------------

mf

The mf terminal driver creates a input file to the MetaFont program. Thus a
figure may be used in the TeX document in the same way as a character is.

To use the plot in a document the MetaFont program must be run with the
output file from GnuPlot as input. Thus, the user needs a basic knowledge
of the font creating process and inclusion of a new font in a document.
However, if the Metafont program is set up properly at the local site an
unexperienced user could perform the operation without much trouble.

The text support is based on a MetaFont character set. Currently the
Computer Modern Roman font set is input but the user are in principal free
to chose whatever fonts he/she needs. The MetaFont source files for the
chosen font must be available. Each character is stored in a separate
picture variable in MetaFont. These variables may be manipulated (rotated,
scaled etc.) when characters are needed. The drawback is the interpretation
time in the MetaFont program. On some machines (i.e. PC) the limited amount
of memory available may also cause problem if too many pictures are stored.

Metafont Instructions

---------------------------------------------------------------------------

Metafont Instructions

- Set your terminal to metafont:

  set terminal mf

- Select an output-file, e.g.:

  set output "myfigures.mf"

- Do your plots. Each plot will generate a separate character. Its default
size will be 5*3 inches. You can change the size by saying set size 0.5,0.5
or whatever fraction of the default size you want to have.

- Quit gnuplot.

- Generate a tfm- and gf-file by running metafont on the output of gnuplot.
Since the plot is quite large (5*3 in), you will have to use a version of
metafont that has a value of at least 150000 for memmax. On Unix-systems
these are conventionally installed under the name bigmf. For the following
assume that the command virmf stands for a big version of metafont. For
example:

- Invoke metafont:

    virmf '&plain'

- Select the output device: At the metafont prompt ('*') type:

    \mode:=CanonCX;     % or whatever printer you use

- Optionally select a magnification:

    mag:=1;             % or whatever you wish

- Input the gnuplot-file:

    input myfigures.mf

On a typical Unix machine there will usually be a script called mf that
executes virmf '&plain', so you probably can substitute mf for virmf
&plain. This will generate two files: mfput.tfm and mfput.$$$gf (where $$$
indicates the resolution of your device). The above can be conveniently
achieved by typing everything on the command line, e.g.: virmf '&plain'
'\mode:=CanonCX; mag:=1; input myfigures.mf' In this case the output files
will be named myfigures.tfm and myfigures.300gf.

- Generate a pk-file from the gf-file using gftopk:

  gftopk myfigures.300gf myfigures.300pk

The name of the output-file for gftopk depends on the dvi-driver you use.
Ask your local TeX-administrator about the naming conventions. Next, either
install the tfm- and pk-files in the appropriate directories, or set your
environment-variables properly. Usually this involves setting TEXFONTS to
include the current directory and do the same thing for the
environment-variable that your dvi-driver uses (no standard name here...).
This step is necessary so that TeX will find the font-metric file and your
dvi-driver will find the pk-file.

- To include your plots in your document you have to tell TeX the font:

  \font\gnufigs=myfigures

Each plot you made is stored in a single character. The first plot is
character 0, the second is character 1, and so on... After doing the above
step you can use the plots just like any other characters. Therefore, to
place plots 1 and 2 centered in your document, all you have to do is:

  \centerline{\gnufigs\char0}
  \centerline{\gnufigs\char1}

in plain TeX. For LaTeX you can, of course, use the picture environment and
place the plot according to your wishes using the \makebox and \put macros.

It saves you a lot of time, once you have generated the font, since TeX
handles the plots as characters and uses minimal time to place them. Also
the documents you make change more often, than the plots do. Also it saves
a lot of TeX-memory. One last advantage of using the metafont-driver is
that the dvi-file really remains device independent, because no
\special-commands are used as in the eepic- and tpic-drivers.

---------------------------------------------------------------------------

mif

Several options may be set in the MIF 3.00 driver.

Syntax:

     set terminal mif {<pentype>} {<curvetype>} {<help>}

<pentype> selects "colour" of the graphics.

     colour     plot lines with line types >= 0 in colour (MIF sep. 2-7).
     monochrome plot all line types in black (MIF sep. 0).

<curvetype> selects how "curves" are plotted.

     polyline   plot curves as continuous curves.
     vectors    plot curves as collections of vectors

<help> print online help on standard error output.

     help       print a short description of the usage, and the options
     ?          print a short description of the usage

This terminal driver produces Frame Maker MIF format version 3.00. It plots
in MIF Frames with the size 15*10 [cm], and plot primitives with the same
pen will be grouped in the same MIF group. Plot primitives in a gnuplot
plot will be plotted in a MIF Frame, and several MIF Frames are collected
in one large MIF Frame. Plot primitives with line types >= 0 will as
default be drawn in colour. As default curves are plotted as continuous
lines. The MIF font used for text is "Times".

Examples:

     set term mif
     set term mif vectors
     set term mif help

---------------------------------------------------------------------------

nec-cp6

One option may be set in the nec-cp6 driver. The resolution of this driver
is 400x320.

Syntax:

        set terminal nec-cp6 monochrome
        set terminal nec-cp6 color
        set terminal nec-cp6 draft

---------------------------------------------------------------------------

pbm

Several options may be set in the PBMplus driver.

Syntax:

        set terminal pbm {<fontsize>} {<colormode>}

where <fontsize> is small, medium, or large and <colormode> is monochrome,
gray or color. Default size is 640 pixels wide and 480 pixels high. The
output for monochrome is a portable bitmap (one bit per pixel). The output
for gray is a portable graymap (three bits per pixel). The output for color
is a portable pixmap (color, four bits per pixel). The output of these
drivers can be used with Jef Poskanzer's excellent PBMPLUS package which
provides programs to convert the above PBMPLUS formats to GIF, TIFF,
MacPaint, Macintosh PICT, PCX, X11 bitmap and many others.

Examples:

        set term pbm small
        set size 2,2
        set term pbm color medium

---------------------------------------------------------------------------

pcl5

Three options may be set in the pcl5 driver. The driver actually uses
HPGL-2 but there is a name conflict among the terminal devices.

Syntax:

        set terminal pcl5 {<mode>} {<font>} {<fontsize>}

where <mode> is landscape, or portrait, <font> is stick, univers, or
cg_times, and fontsize is the size in points.

        set terminal pcl5 landscape

---------------------------------------------------------------------------

postscript

Several options may be set in the PostScript driver.

Syntax:

        set terminal postscript {<mode>} {<color>} {<dashed>}
                                {"<fontname>"} {<fontsize>}

where <mode> is landscape, portrait, eps or default. Selecting default sets
all options to their defaults. <color> is either color or monochrome.
<dashed> is either solid or dashed. "<fontname>" is the name of a valid
PostScript font. <fontsize> is the size of the font in PostScript points.
Defaults are landscape, monochrome, dashed, "Helvetica", and 14pt. Default
size of PostScript plot is landscape mode 10 inches wide and 7 inches high.

To get EPS output, use the eps mode and make only one plot per file. In eps
mode the whole plot is halved in size; the fonts are half the given size,
and the plot is 5 inches wide and 3.5 inches high.

Examples:

        set term postscript default       # old postscript
        set term postscript landscape 22  # old psbig
        set term postscript eps 14   # old epsf1
        set term postscript eps 22   # old epsf2
        set size 0.7,1.4
        set term post portrait color "Times-Roman" 14

---------------------------------------------------------------------------

enhanced postscript

The "Enhanced PostScript" driver has extended capabilities beyond the
regular PostScript driver. Several options may be set in the Enhanced
PostScript driver.

Syntax:

        set terminal enhpost {<mode>} {<color>} {<dashed>}
                             {<duplexing>} {"<fontname>"} {<fontsize>}

where <mode> is landscape, portrait, eps or default. Selecting default sets
all options to their defaults. <color> is either color or monochrome.
<dashed> is either solid or dashed. <duplexing> is either simplex or duplex
(don't set this if your printer can't do it). "<fontname>" is the name of a
valid PostScript font. <fontsize> is the size of the font in PostScript
points. Defaults are landscape, monochrome, dashed, 'printer-default-plex',
"Helvetica", and 14pt. Default size of Enhanced PostScript plot is
landscape mode 10 inches wide and 7 inches high.

To get EPS output, use the eps mode and make only one plot per file. In eps
mode the whole plot is halved in size; the fonts are half the given size,
and the plot is 5 inches wide and 3.5 inches high.

Examples:

        set term enhpost landscape 22
        set term enhpost eps 14
        set term enhpost landscape simplex
        set size 0.7,1.4
        set term enhpost portrait color "Times-Roman" 14

This "enhanced" driver allows any text to contain the following special
formatting instructions (e.g., use the SET FORMAT command to put them in
for axis scales):

 Control      Examples        Explanation
  ^           a^x             superscript
  _           a_x             subscript
  @           @x or a@^b_c    phantom box (occupies no width)

{text} can be used to allow multiple-character text, where only a single
character is expected (e.g., 2^{10}). To change the font and/or size, use
the full form: {/[fontname][=fontsize] text} (For example, {/Symbol=20 G}
is a 20 point GAMMA). (The '/' character MUST be the first character after
the '{'.)

The phantom box is useful for a@^b_c to align superscript and subscript,
and for overwriting an accent on a letter. It is common sense to put the
shorter of the two in the phantom box.

You can access special symbols numerically by specifying \character-code
(in octal), e.g., {/Symbol \245} is infinity.

You can escape control characters using \, e.g., \\, \{, \}, \^, \@

---------------------------------------------------------------------------

pslatex

There are a few options for the pslatex driver.

Syntax:

        set terminal pslatex {<color>} {<rotate>} {auxfile}

<color> is either color or monochrome. if default is specified, the plot
will have rotated text and be in monochrome, all in one file. <rotate> is
either rotate or norotate and determines if the vertical axis label is
rotated.

If auxfile is specified, directs the driver to put the postscript commands
into an auxiliary file instead of directly into the latex file. This is
useful if your plots are large, and dvips cannot handle the picture. The
postscript file name for this option is determined by replacing the
trailing .tex with .ps in the output file name.

Example:

        set term pslatex auxfile    # put postscript parts in file foo.ps
        set output "foo.tex"

---------------------------------------------------------------------------

fig

The fig terminal device have the option of either color or monochrome and
small or large image. The default is monochrome and small. To select color,
use:

       set terminal fig color

To select large, use:

       set terminal fig large

The large option is a substitute for the bfig terminal in earlier version,
which is no longer supported.

---------------------------------------------------------------------------

regis

The regis terminal device has the option of using 4 or 16 colors. The
default is 4. For example:

       set term regis 16

---------------------------------------------------------------------------

table

Instead of producing a picture, term type table prints out the evaluation
results in a multicolumn ASCII table of X Y Z values. For those times when
you really want to see the numbers, now you can see them on the screen or
save to a file.

---------------------------------------------------------------------------

uniplex

The uniplex driver is able to combine several plots in one image. The
option portrait causes the image to be drawn in a window where the width is
about 2/3 of the hight (default is landscape: The image hight is ca 2/3 of
the width). Fontsize may also be spesified (sizes 1-8). Only one image is
allowed pr file. If a 'X' is include in the set output filename, the 'X' is
substituted with a seqentional plot number.

Options are:

      portrait
      landscape        (default)
      [ x , y ]        (where x and y is number of plots in x- and y direction
                         of the image)
      n                (where n is fontsize (1-8))

To plot 6 plots in one image in two columns in portrait orientation:

      set term uniplex po [2,3]

---------------------------------------------------------------------------

windows

Three options may be set in the windows driver.

Syntax:

        set terminal windows {<color>} {"<fontname>"} {<fontsize>}

<color> is either color or monochrome. "<fontname>" is the name of a valid
Windows font. <fontsize> is the size of the font in points.

graph-menu
printing
text-menu
wgnuplot.ini
windows3.0

---------------------------------------------------------------------------

graph-menu

The gnuplot graph window has the following options on a pop up menu
accessed by pressing the right mouse button or selecting Options from the
system menu:

Bring to Top when checked brings the graph window to the top after every
plot.

Color when checked enables color linestyles. When unchecked it forces
monochrome linestyles.

Copy to Clipboard copies a bitmap and a Metafile picture.

Background... sets the window background color.

Choose Font... selects the font used in the graphics window.

Line Styles... allows customization of the line colors and styles.

Print... prints the graphics windows using a Windows printer driver and
allows selection of the printer and scaling of the output. The output
produced by Print is not as good as that from gnuplot's own printer
drivers.

Update wgnuplot.ini saves the current window locations, window sizes, text
window font, text window font size, graph window font, graph window font
size, background color and linestyles to the initialisation file
WGNUPLOT.INI.

---------------------------------------------------------------------------

printing

In order of preference, graphs may be be printed in the following ways.

1. Use the gnuplot command set terminal to select a printer and set output
to redirect output to a file.

2. Select the Print... command from the gnuplot graph window. An extra
command screendump does this from the text window.

3. If set output "PRN" is used, output will go to a temporary file. When
you exit from gnuplot or when you change the output with another set output
command, a dialog box will appear for you to select a printer port. If you
choose OK, the output will be printed on the selected port, passing
unmodified through the print manager. It is possible to accidently (or
deliberately) send printer output meant for one printer to an incompatible
printer.

---------------------------------------------------------------------------

text-menu

The gnuplot text window has the following options on a pop up menu accessed
by pressing the right mouse button or selecting Options from the system
menu:

Copy to Clipboard copies marked text to the clipboard.

Paste copies text from the clipboard as if typed by the user.

Choose Font... selects the font used in the text window.

System Colors when selected makes the text window honor the System Colors
set using the Control Panel. When unselected, text is black or blue on a
white background.

Update wgnuplot.ini saves the current text window location, text window
size, text window font and text window font size to the initialisation file
WGNUPLOT.INI.

MENU BAR

If the menu file WGNUPLOT.MNU is found in the same directory as
WGNUPLOT.EXE, then the menu specified in WGNUPLOT.MNU will be loaded.

Menu commands are:

  [Menu]       Start a new menu with the name on the following line
  [EndMenu]    End current menu.
  --           Insert a horizontal menu separator
  |            Insert a vertical menu separator
  [Button]     Put next macro on a push button instead of a menu.

Macros take two lines with the macro name (menu entry) on the first line
and the macro on the second line. Leading spaces are ignored.

Macros commands are:

  [INPUT]      Input string with prompt terminated by [EOS] or {ENTER}
  [EOS]        End Of String terminator.  Generates no output.
  [OPEN]       Get name of file to open from list box, with title of
               list box terminated by [EOS], followed by default
               filename terminated by [EOS] or {ENTER}
               This uses COMMDLG.DLL from Windows 3.1.
  [SAVE]       Get name of file to save.  Similar to [OPEN]

Macros character substitutions are:

  {ENTER}      Carriage Return '\r'
  {TAB}        Tab     '\011'
  {ESC}        Escape  '\033'
  {^A}         '\001'
  ...
  {^_}         '\031'

Macros are limited to 256 characters after expansion.

---------------------------------------------------------------------------

wgnuplot.ini

Windows gnuplot will read some of its options from the [WGNUPLOT] section
of WGNUPLOT.INI in the Windows directory. An example WGNUPLOT.INI file is
shown below.

 [WGNUPLOT]
 TextOrigin=0 0
 TextSize=640 150
 TextFont=Terminal,9
 GraphOrigin=0 150
 GraphSize=640 330
 GraphFont=Arial,10
 GraphColor=1
 GraphToTop=1
 GraphBackground=255 255 255
 Border=0 0 0 0 0
 Axis=192 192 192 2 2
 Line1=0 0 255 0 0
 Line2=0 255 0 0 1
 Line3=255 0 0 0 2
 Line4=255 0 255 0 3
 Line5=0 0 128 0 4

The GraphFont entry specifies the font name and size in points. The 5
numbers given in the Border, Axis and Line entries are the Red intensity
(0-255), Green intensity, Blue intensity, Color Linestyle and Mono
Linestyle. Linestyles are 0=SOLID, 1=DASH, 2=DOT, 3=DASHDOT, 4=DASHDOTDOT.
In the example WGNUPLOT.INI file above, Line 2 is a green solid line in
color mode, or a dashed line in monochrome mode. The default line width is
1 pixel. If Linestyle is negative it specifies the width of a SOLID line in
pixels. Line1 and any linestyle used with the points style must be SOLID
with unit width.

---------------------------------------------------------------------------

windows3.0

Windows 3.1 is preferred, but WGNUPLOT will run under Windows 3.0 with the
following restrictions:

1. COMMDLG.DLL and SHELL.DLL (available with Windows 3.1 or Borland C++
3.1) must be in the windows directory.

2. WGNUPLOT.HLP produced by Borland C++ 3.1 is in Windows 3.1 format. You
need to use the WINHELP.EXE supplied with Borland C++ 3.1.

3. It won't run in real mode due to lack of memory.

4. Truetype fonts are not available in the graph window.

5. Drag-drop does not work.

---------------------------------------------------------------------------

tics

By default, tics are drawn inwards from the border on all four sides. The
set tics command can be used to change the tics to be drawn outwards on the
left and bottom borders only. This is useful when doing impulse plots.

Syntax:

        set tics {<direction>}
        show tics

where <direction> may be in or out. set tics defaults to in.

See also the set xtics, set ytics, and set ztics command for more control
of tic marks and set mxtics, and set mytics for minor tic marks Using
splot, in 3-d plots, one can adjust the relative height of the vertical (Z)
axis using set ticslevel. The numeric argument provided specifies the
location of the bottom of the scale. a zero will put it on the bottom grid
and any positive number somewhere along the z axis.

Syntax:

        set ticslevel {<level>}
        show tics

where <level> is a non negative numeric argument. For example,

        set ticslevel 0.5

sets the tics level to the default value.

See also the set view. The size of the major tic marks can be adjusted via
set ticscale. The default size is 1.0. Minor tic marks are 0.5*ticscale.
Note that it is possible to have the tic marks pointing outward using a
negative size.

Syntax:

        set ticscale {<size>}
        show tics

---------------------------------------------------------------------------

time

The optional set time places the time and date of the plot either at the
top or bottom of the left margin. The exact location is device dependent.

Syntax:

        set time {<xoff>}{,<yoff>}
        set notime
        show time

Specifying constants <xoff> or <yoff> as optional offsets for the time will
move the time <xoff> or <yoff> character screen coordinates. For example,

        set time ,-3

will change only the y offset of the time, moving the title down by roughly
the height of three characters.

---------------------------------------------------------------------------

timefmt

This command applies to timeseries where data is composed of dates/times.
It has no meaning unless the comand set {x,y,z}data time is given also. The
string argument tells gnuplot how to read timedata from the datafile. Valid
conversion codes are: %d (day of month,1-31), %m (month,1-12), %y
(year,0-99), %Y (year, 4 digits), %j (day of year,1-365), %H (hour,0-24),
%M (minute,0-60), %S (second,0-60). Any character is allowed in the string
(included space), but must match exactly. Backslash-octals (\nnn) is
converted to char, also \t (tab) is understood. If there is no separating
character between the date/time elements, then %d, %m, %y, %H, %M and %S
read 2 digits each, %Y read 4 digits and %j reads 3 digits. The columns in
the timedata counts one column in the "using n:n" specification.

See also set {x,y,z}data.

Example:

        set timefmt "%d/%m/%Y\t%H:%M"

tells gnuplot to read date and time separated by tab. Timeseries Demo.

---------------------------------------------------------------------------

title

The set title command produces a plot title that is centered at the top of
the plot. Using the optional x,y screen offsets, the title can be placed
anywhere on the plot. set title with no parameters clears the title.

Syntax:

         set title {"<title-text>"} {<xoff>}{,<yoff>}
         show title

Specifying constants <xoff> or <yoff> as optional offsets for the title
will move the title <xoff> or <yoff> character screen coordinates. Note
these are screen coordinates and not plot coordinates. For example,

         set title ,-1

will change only the y offset of the title, moving the title down by
roughly the height of one character.

Multiline titles is supported by including newlines (\n) in the string. The
string is also scanned for backslash-octal conversion (\nnn), thus making
it possible to include any character in the string.

(The EEPIC, Imagen, Uniplex, LaTeX, and TPIC drivers allow \\ in a string
to specify a newline.)

---------------------------------------------------------------------------

trange

The set trange command sets the parametric range used to compute x and y
values when in parametric mode. If not in parametric mode (see set
parametric) then this range is not used. This command does not affect x/y
autoscaling or x/y ranges.

This range may also be specified on the plot command line when in
parametric mode.

Syntax:

        set trange [{<tmin> : <tmax>}]

where <tmin> and <tmax> terms are constants or expressions or a star to set
autoscale.

Both the <tmin> and <tmax> terms are optional. Anything omitted will not be
changed, so

        set trange [:10]

changes tmax to 10 without affecting tmin. See also set urange and set
parametric.

---------------------------------------------------------------------------

urange

The set urange and set vrange commands sets the parametric ranges used to
compute x, y, and z values when in splot parametric mode. If not in
parametric mode (see set parametric) then these ranges are not used. This
command does not affect x/y autoscaling or x/y ranges.

This range may also be specified on the splot command line when in
parametric mode. See plot for more information

Syntax:

        set urange [{<umin> : <umax>}]

where <umin> and <umax> terms are constants or expressions or a star to set
autoscale.

Both the <umin> and <umax> terms are optional. Anything omitted will not be
changed, so

        set urange [:10]

changes umax to 10 without affecting umin. See also set trange.

---------------------------------------------------------------------------

variables

The show variables command lists all user-defined variables and their
values.

Syntax:

        show variables

---------------------------------------------------------------------------

view

The set view command sets the view point for splots. This command controls
the way the 3-d coordinates of the plot are mapped into the 2-d screen
space. This command provides controls to both rotation and scaling of the
plotted data but supports orthographic projections only.

Syntax:

        set view <rot_x> {,{<rot_z>}{,{<scale>}{,<scale_z>}}}
        show view

where <rot_x> and <rot_z> control the rotation angles (in degrees) along a
virtual 3-d coordinate system aligned with the screen such that the screen
horizontal axis is x, screen vertical axis is y, and the axis perpendicular
to the screen is z. <rot_x> is bounded to the [0:180] range with a default
of 60 degrees, while <rot_z> is bounded to the [0:360] range with a default
of 30 degrees. <scale> controls the scaling of the entire splot, while
<scale_z> scales the z axis only. Both scales default to 1.0.

Examples:

        set view 60, 30, 1, 1
        set view ,,0.5

The first sets all the four default values. The second changes only scale,
to 0.5.

See also set ticslevel.

---------------------------------------------------------------------------

vrange

The set vrange command is similar to the set urange command. Please see set
urange.

---------------------------------------------------------------------------

xdata

This command sets the datatype on the xaxis to date/time. See set timefmt
to tell gnuplot how to read the data. The date/time is converted to seconds
from start of the century. There is currently only one timefmt, which
implies that all the date/time columns must confirm to this format.
Specification of ranges should be supplied as qouted strings according to
this format to avoid interpretation of the date/time as expression.

The function "strftime" (do "man strftime" to look it up) is used to print
ticmark labels. Gnuplot tries to figure out a resonable format for this
unless the set format x "string" has supplied something that does not look
like a decimal format (more than one '%' or not %f nor %g).

Syntax:

        set xdata time

To turn the xaxis data back to the default:

        set xdata

---------------------------------------------------------------------------

xlabel

The set xlabel command sets the x-axis label that is centered along the x
axis. Using the optional x,y screen offsets, the label can be placed
anywhere on the plot. set xlabel with no parameters clears the label. The
string is scanned for backslash-octal (\nnn) conversion.

Syntax:

         set xlabel {"<label>"} {<xoff>}{,<yoff>}
         show xlabel

Specifying constants <xoff> or <yoff> as optional offsets for the label
will move the label <xoff> or <yoff> character screen coordinates. For
example,

         set xlabel -1

will change only the x offset of the xlabel, moving the label roughly one
character width to the left.

Multiline label is achieved by simply putting a linefeed in the text (\n).
Example:

        set xlabel "This is the first line.\nThe second.\nThe third."

(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)

---------------------------------------------------------------------------

xmargin

This command gives control over the xaxis offset. If this is not given,
gnuplot computes the offset based on the number of lines in the ylabel and
the length of the ytic marks (plot, not splot). The margin units is
character.

Syntax:

        set xmargin <chars>
   sets the margin.
        set xmargin
   sets the margin back to computed.

---------------------------------------------------------------------------

xrange

The set xrange command sets the horizontal range that will be displayed.
This command turns x axis autoscaling off.

This range may also be specified on the plot command line.

Syntax:

        set xrange [{<xmin> : <xmax>}]

where <xmin> and <xmax> terms are constants or expressions or a star to set
autoscaling. If xdata is date/time give the range as a quoted string
according to the set timefmt format.

Both the <xmin> and <xmax> terms are optional. Anything omitted will not be
changed, so

        set xrange [:10]

changes xmax to 10 without affecting xmin (may still be autoscaled). And

        set xrange [:*]

sets autoscaling in the xmax direction.

---------------------------------------------------------------------------

xtics

Fine control of the x axis tic marks is possible with the set xtics
command. The x-axis tic marks may be turned off with the set noxtics
command. They may be turned on (the default state) with set xtics.

Syntax:

         set xtics { {<start>, <incr>{, <end>}} |
                     {({"<label>"} <pos> {, {"<label>"} <pos>}...)} }
         set noxtics
         show xtics

The <start>, <incr>, <end> form specifies that a series of tics will be
plotted on the x axis between the x values <start> and <end> with an
increment of <incr>. If <end> is not given it is assumed to be infinity.
The increment may be negative. For example,

          set xtics 0,.5,10

makes tics at 0, 0.5, 1, 1.5, ..., 9.5, 10.

The ("<label>" <pos>, ...) form allows arbitrary tic positions or
non-numeric tic labels. A set of tics are a set of positions, each with its
own optional label. Note that the label is a string enclosed by quotes, and
may be a constant string, such as "hello", or contain formatting
information for the tic number (which is the same as the position), such as
"%3f clients". See set format for more information about this case. The
label may even be empty. Examples:

         set xtics ("low" 0, "medium" 50, "high" 100)
         set xtics (1,2,4,8,16,32,64,128,256,512,1024)
         set xtics ("bottom" 0, "" 10, "top" 20)

Tics will only be plotted when in range.

In case of timeseries data position values must be given as qouted
dates-times according to the format timefmt.

---------------------------------------------------------------------------

mxtics

Minor tic marks are the default along the x-axis. The number of minor tics
between major tic marks can be adjusted. Minor tic marks are turned off
with set nomxtics.

Syntax:

       set mxtics {<freq>}
       set nomxtics
       show mxtics

<freq> is the number of sub-intervals (NOT number of minor tics!) between
major tics (10 is default so there are 9 minor tics between major tics).

---------------------------------------------------------------------------

mytics

Minor tic marks are the default along the y-axis. The number of minor tics
between major tic marks can be adjusted. Minor tic marks are turned off
with set nomytics.

Syntax:

       set mytics {<freq>}
       set nomytics
       show mytics

<freq> is the number of sub-intervals (NOT number of minor tics!) between
major tics (10 is default so there are 9 minor tics between major tics).

---------------------------------------------------------------------------

xdtics

The set xdtics commands converts the x axis tic marks to days of the week
where 0=Sun and 6=Sat. Overflows are converted modulo 7 to dates.

Examples:

       set xdtics

Sets x axis tics in days.

The set ydtics set zdtics and set noydtics set nozdtics commands work
identically. See also the set format command.

---------------------------------------------------------------------------

xmtics

The set xmtics commands converts the x axis tic marks to months of the
years where 1=Jan and 12=Dec. Overflows are converted modulo 12 to months.

Examples:

       set xmtics

Sets x axis tics into months.

The set ymtics set zmtics and set noymtics set nozmtics commands work
identically. See also the set format command.

---------------------------------------------------------------------------

xzeroaxis

set xzeroaxis draws the x-axis. By default, this option is on. set
noxzeroaxis causes GNUPLOT to omit the x-axis.

Syntax:

        set xzeroaxis
        set noxzeroaxis
        show xzeroaxis

---------------------------------------------------------------------------

ydata

Sets yaxis data to timeseries (dates/times). See set xdata.

---------------------------------------------------------------------------

ylabel

The set ylabel command sets the y-axis label. The position of this label
depends on the terminal, and can be one of the following three positions
(the position can be adjusted with optional parameters).

1. Horizontal text flushed left at the top left of the plot. Terminals that
cannot rotate text will probably use this method.

2. Vertical text centered vertically at the left of the plot. Terminals
that can rotate text will probably use this method.

3. Horizontal text centered vertically at the left of the plot. The EEPIC,
LaTeX and TPIC drivers use this method. The user must insert line breaks
using \\ to prevent the ylabel from overwriting the plot. To produce a
vertical row of characters, add \\ between every printing character (but
this is ugly).

Syntax:

         set ylabel {"<label>"} {<xoff>}{,<yoff>}
         show ylabel

With no parameters, the label is cleared. Specifying constants <xoff> or
<yoff> as optional offsets for the label will move the label <xoff> or
<yoff> character screen coordinates. For example,

         set ylabel -1

will change only the x offset of the ylabel, moving the label roughly one
character width left of its default position. This is especially useful
with the LaTeX driver.

Multiline ylabel is supported, put a newline in the string (\n). The string
is also scanned for backslash-octal (\nnn) conversion.

(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)

---------------------------------------------------------------------------

yrange

The set yrange command sets the vertical range that will be displayed. This
command turns y axis autoscaling off.

This range may also be specified on the plot command line.

Syntax:

        set yrange [{<ymin> : <ymax>}]

where <ymin> and <ymax> terms are constants or expressions or a star to set
autoscale.

Both the <ymin> and <ymax> terms are optional. Anything omitted will not be
changed, so

        set yrange [:10]

changes ymax to 10 without affecting ymin. To set ymin and autoscaling i
the ymax direction:

        set yrange [0:*]

---------------------------------------------------------------------------

ytics

The set ytics and set noytics commands are similar to the set xtics and set
noxtics commands. Please see set xtics. See set mytics for minor tic marks
along y axis.

---------------------------------------------------------------------------

ydtics

The set ydtics and set noydtics commands are similar to the set xdtics and
set noxdtics commands. Please see set xdtics.

---------------------------------------------------------------------------

ymtics

The set ymtics and set noymtics commands are similar to the set xmtics and
set noxmtics commands. Please see set xmtics.

---------------------------------------------------------------------------

yzeroaxis

set yzeroaxis draws the y-axis. By default, this option is on. set
noyzeroaxis causes GNUPLOT to omit the y-axis.

Syntax:

        set yzeroaxis
        set noyzeroaxis
        show yzeroaxis

---------------------------------------------------------------------------

zdata

Set zaxis date to timeseries (dates/times). Please see set xdata.

---------------------------------------------------------------------------

zero

The zero value is the default threshold for values approaching 0.0. GNUPLOT
will not plot a point if its imaginary part is greater in magnitude than
the zero threshold. Axis ranges cannot be less than The zero value is the
default threshold for values approaching 0.0. GNUPLOT will not plot a point
if its imaginary part is greater in magnitude than the zero threshold. Axis
ranges cannot be less than zero. The default zero value is 1e-8. This can
be changed with the set zero command.

Syntax:

        set zero <expression>
        show zero

---------------------------------------------------------------------------

zeroaxis

set zeroaxis draws the x-axis and y-axis. By default, this option is on.
set nozeroaxis causes GNUPLOT to omit the axes, and is equivalent to set
noxzeroaxis; set noyzeroaxis.

Syntax:

        set zeroaxis
        set nozeroaxis
        show zeroaxis

See set xzeroaxis and set yzeroaxis.

---------------------------------------------------------------------------

zlabel

The set zlabel command sets the z-axis label that is centered along the z
axis. Using the optional x,y screen offsets, the label can be placed
anywhere on the plot. set zlabel with no parameters clears the label.

Syntax:

         set zlabel {"<label>"} {<xoff>}{,<yoff>}
         show zlabel

Specifying constants <xoff> or <yoff> as optional offsets for the label
will move the label <xoff> or <yoff> character screen coordinates. For
example,

         set zlabel ,1

will change only the y offset of the zlabel, moving the label roughly one
character height up.

The zlabel will be drawn whenever surfaces or contours are plotted, in the
space above the grid level.

Multiline labels is supported, put a newline (\n) in the string.
Backslash-octal conversion (\nnn) on the string is performed. Example:

        set zlabel "Line one.\nLine two with 8-bit char: \345."

(The EEPIC, Imagen, LaTeX, and TPIC drivers allow \\ in a string to specify
a newline.)

---------------------------------------------------------------------------

zrange

The set zrange command sets the vertical range that will be displayed. This
command turns z axis autoscaling off. The zrange is used only by splot and
is ignored by plot.

This range may also be specified on the splot command line.

Syntax:

        set zrange [{<zmin> : <zmax>}]

where <zmin> and <zmax> terms are constants or expressions or a star to set
autoscale in one direction.

Both the <zmin> and <zmax> terms are optional. Anything omitted will not be
changed, so

        set zrange [2:]

changes zmin to 2 without affecting zmax.

        set zrange [:*]

sets autoscale in then zmax direaction.

---------------------------------------------------------------------------

ztics

The set ztics and set noztics commands are similar to the set xtics and set
noxtics commands. Please see set xtics.

---------------------------------------------------------------------------

zdtics

The set zdtics and set nozdtics commands are similar to the set xdtics and
set noxdtics commands. Please see set xdtics.

---------------------------------------------------------------------------

zmtics

The set zmtics and set nozmtics commands are similar to the set xmtics and
set noxmtics commands. Please see set xmtics.

---------------------------------------------------------------------------

shell

The shell command spawns an interactive shell. To return to GNUPLOT, type
logout if using VMS, exit or the END-OF-FILE character if using Unix,
endcli if using AmigaDOS, or exit if using MS-DOS or OS/2.

A single shell command may be spawned by preceding it with the ! character
($ if using VMS) at the beginning of a command line. Control will return
immediately to GNUPLOT after this command is executed. For example, in VMS,
AmigaDOS, MS-DOS or OS/2,

     ! dir

prints a directory listing and then returns to GNUPLOT.

On an Atari, the ! command first checks whether a shell is already loaded
and uses it, if available. This is practical if GNUPLOT is run from gulam,
for example.

---------------------------------------------------------------------------

splot

Three-dimensional surface and contour plotting is available in GNUPLOT with
the splot command. See the plot command for features common to the plot
command.

See also set contour, set cntrparam, and set surface. Non parametric Splot
Demos Parametric Splot Demos.

Binary Data

---------------------------------------------------------------------------

Binary Data

Gnuplot will dynamically determine if a datafile is ASCII or binary. ASCII
data files are discussed in the plot section. For three dimensions, single
precision floats are stored as follows:

      <ncols> <x0> <x1> <x2> ...
      <y0> <z0,0> <z0,1> <z0,2> ...
      <y1> <z1,0> <z1,1> <z1,2> ...

which is converted into triplet:

      <x0> <y0> <z0,0>
      <x0> <y1> <z0,1>
      <x0> <y2> <z0,2>

      <x1> <y0> <z1,0>
      <x1> <y1> <z1,1>
      <x1> <y2> <z1,2>

These triplets are then converted into gnuplot iso_curves and then uses
gnuplot to do the rest of the plotting.

A collection of matrix and vector manipulation routines (in C) are provided
in gnubin.c. The routine to write binary data is

 int fwrite_matrix(file,m,nrl,nrl,ncl,nch,row_title,column_title)

An example of using these routines is provided in the file bf_test.c. The
corresponding demo file is demo/binary.dem. Binary File Splot Demo.

---------------------------------------------------------------------------

start-up

When GNUPLOT is run, it looks for an initialization file to load. This file
is called .gnuplot on Unix and AmigaDOS systems, and GNUPLOT.INI on other
systems. If this file is not found in the current directory, the program
will look for it in the home directory (under AmigaDOS, AtariTOS, MS-DOS
and OS/2, the environment variable GNUPLOT should contain the name of this
directory). Note: if NOCWDRC is defined during the installation, GNUPLOT
will not read from the current directory.

If this file is found, GNUPLOT executes the commands in this file. This is
most useful for setting the terminal type and defining any functions or
variables that are used often.

---------------------------------------------------------------------------

substitution

Command-line substitution is specified by a system command enclosed in
backquotes. This command is spawned and the output it produces replaces the
name of the command (and backquotes) on the command line.

Newlines in the output produced by the spawned command are replaced with
blanks.

Command-line substitution can be used anywhere on the GNUPLOT command line.

Example:

This will run the program leastsq and replace leastsq (including
backquotes) on the command line with its output:

         f(x) = leastsq

or, in VMS

         f(x) = run leastsq

---------------------------------------------------------------------------

update

Syntax: update <filename>

This command updates the start parameter assignments in a start parameter
file as specified in the fit section. Each parameter will be replaced by
its actual value. This is useful for restarting a converged or stopped fit
again.

SEE ALSO: fit

---------------------------------------------------------------------------

user-defined

New user-defined variables and functions of one through five variables may
be declared and used anywhere.

User-defined function syntax:

        <function-name> ( <dummy1> {,<dummy2> {, ...} } ) = <expression>

where <expression> is defined in terms of <dummy1> through <dummy5>.

User-defined variable syntax:

        <variable-name> = <constant-expression>

Examples:

        w = 2
        q = floor(tan(pi/2 - 0.1))
        f(x) = sin(w*x)
        sinc(x) = sin(pi*x)/(pi*x)
        delta(t) = (t == 0)
        ramp(t) = (t > 0) ? t : 0
        min(a,b) = (a < b) ? a : b
        comb(n,k) = n!/(k!*(n-k)!)
        len3d(x,y,z) = sqrt(x*x+y*y+z*z)

Note that the variable pi is already defined.

See show functions and show variables.

---------------------------------------------------------------------------

bugs

The bessel functions do not work for complex arguments.

The gamma function does not work for complex arguments.

There is a bug in the stdio library for old Sun operating systems (SunOS
Sys4-3.2). The "%g" format for 'printf' sometimes incorrectly prints
numbers (e.g., 200000.0 as "2"). Thus, tic mark labels may be incorrect on
a Sun4 version of GNUPLOT. A work-around is to rescale the data or use the
set format command to change the tic mark format to "%7.0f" or some other
appropriate format. This appears to have been fixed in SunOS 4.0.

Another bug: On a Sun3 under SunOS 4.0, and on Sun4's under Sys4-3.2 and
SunOS 4.0, the 'sscanf' routine incorrectly parses "00 12" with the format
"%f %f" and reads 0 and 0 instead of 0 and 12. This affects data input. If
the data file contains x coordinates that are zero but are specified like
'00', '000', etc, then you will read the wrong y values. Check any data
files or upgrade the SunOS. It appears to have been fixed in SunOS 4.1.1.

Microsoft C 5.1 has a nasty bug associated with the %g format for printf.
When any of the formats "%.2g", "%.1g", "%.0g", "%.g" are used, printf will
incorrectly print numbers in the range 1e-4 to 1e-1. Numbers that should be
printed in the %e format are incorrectly printed in the %f format, with the
wrong number of zeros after the decimal point.

To work around this problem, use the %e or %f formats explicitly.

GNUPLOT, when compiled with Microsoft C, did not work correctly on two VGA
displays that were tested. The CGA, EGA and VGA drivers should probably be
rewritten to use the Microsoft C graphics library. GNUPLOT compiled with
Borland C++ uses the Turbo C graphics drivers and does work correctly with
VGA displays.

VAX/VMS 4.7 C compiler release 2.4 also has a poorly implemented %g format
for printf. The numbers are printed numerically correct, but may not be in
the requested format. The K&R second edition says that for the %g format,
%e is used if the exponent is less than -4 or greater than or equal to the
precision. The VAX uses %e format if the exponent is less than -1. The VAX
appears to take no notice of the precision when deciding whether to use %e
or %f for numbers less than 1. To work around this problem, use the %e or
%f formats explicitly. From the VAX C 2.4 release notes: e,E,f,F,g,G Result
will always contain a decimal point. For g and G, trailing zeros will not
be removed from the result.

VAX/VMS 5.2 C compiler release 3.0 has a slightly better implemented %g
format than release 2.4, but not much. Trailing decimal points are now
removed, but trailing zeros are still not removed from %g numbers in
exponential format.

ULTRIX X11R3 has a bug that causes the X11 driver to display "every other"
plot. The bug seems to be fixed in DEC's release of X11R4 so newer releases
of ULTRIX don't seem to have the problem. Solutions for older sites include
upgrading the X11 libraries (from DEC or direct from MIT) or defining
ULTRIX_KLUDGE when compiling the x11.trm file. Note that the kludge is not
an ideal fix, however.

The constant HUGE was incorrectly defined in the NeXT OS 2.0 operating
system. HUGE should be set to 1e38 in plot.h. This error has been corrected
in the 2.1 version of NeXT OS.

Some older models of HP plotters do not have a page eject command 'PG'. The
current HPGL driver uses this command in HPGL_reset. This may need to be
removed for these plotters. The current PCL5 driver uses HPGL/2 for text as
well as graphics. This should be modified to use scalable PCL fonts.

On the Atari version, it is not possible to send output directly to the
printer (using /dev/lp as output file), since CRs are added to LFs in
binary output. As a workaround write the output to a file and copy it to
the printer afterwards using a shell command.

Please report any bugs to bug-gnuplot@dartmouth.edu.

---------------------------------------------------------------------------
Created automatically by doc2html