Addons/graphics/gnuplot

graphics/gnuplot - create gnuplot graphics

Creates gnuplot graphics from J data. Tested with gnuplot V4.

1. Installation
2. Usage
3. Main Verbs
   1. gplot
   2. gsplot
   3. gset
4. Output
5. Usage in Windows
6. Notes
7. Demos
8. Author

Installation

Use JAL/Package Manager or download the gnuplot archive from j601/addons and extract it into the ~addons/graphics/gnuplot folder.

Usage

Load with:

load 'graphics/gnuplot' 

This populates locale pgnuplot.

Main Verbs

There are 3 main verbs: gplot, gsplot, gset.

gplot

Plots 2D graphics:

[cmd] gplot data 

data is either an open array for a single plot, or a boxed list for multiple plots. This has the same format as for Plot.

cmd is options in a list delimited by , in gnuplot format, except that keywords should be spelled in full, e.g. use title not t.

There may be one option list per plot.

The first option list may start with a range indication. The last option list applies thereafter

gsplot

Plots surface graphics. The arguments are as for gplot.

[cmd] gsplot data 

gset

Set one or more gnuplot options, in gnuplot format. You can set more than one option at a time, by delimiting each option with ; .

gset optionlist 

Output

When gnuplot is run it creates two files in the ~temp directory:

gnu.plt      - plot commands
gnu.dat      - data

To display the plot, load gnuplot, then enter at the command prompt, using the correct path name:

load "gnu.plt"

In Windows, you can configure gnuplot to do this automatically.

Usage in Windows

In Windows, define GNUPLOTBIN_pgnuplot_ as the name of the gnuplot bin directory. A good place to define this is your startup script.

If defined, then:

• the contents of gnuplot.ini are prefixed to the output file. This ensures the default values are read on start up.

• wgnuplot.exe is called after generating the plot files.

In particular, the default style for data in gnuplot is points. To change this to lines, add the following to gnuplot.ini:

set style data lines

Notes

Titles default to empty

You can use the double quote character to delimit strings, e.g.

gset 'title "mydata"' 

instead of:

gset 'title ''mydata''' 

Strings must be delimited, i.e. not:

gset 'title mydata' 

You can define GNUPLOTOUT_jgnuplot_ as the output directory for files written by J. By default this is ~temp.

Demos

load 'graphics/gnuplot/gpdemo'  NB. defines gp1, gp2, gp3, gp4

gp1=: 3 : 0
SC=: (;sin@^,:cos@^) steps _1 2 100
gset 'grid'
gset 'title "sin(exp) vs cos(exp)"'
gset 'xlabel "x-axis"'
gset 'ylabel "y-axis"'
'with lines title "sin(exp)", with lines title "cos(exp)"' gplot SC
)

Author

The original script was contributed by L. Fraser Jackson.