plplot

Plot graphs using prolog and gnuplot.

Requirements

gnuplot must be installed and in the path.

To check if gnuplot is installed type: command -v gnuplot. If nothing is printed, this means that gnuplot is missing.

You can download it from http://www.gnuplot.info/download.html and then follow the instructions in the folder.

Usually you need other libraries to install gnuplot as libwxgtk3.0-dev libpango1.0-dev and libreadline5-dev.

Installation

plplot can be installed using pack_install/1

$ swipl
?- pack_install(plplot).

Still does not work on Windows

Example

$ swipl
?- use_module(library(plplot)).
?- plot_point('Title',[1.0, 2.0, 3.0, 4.0, 5.0],[5.0 ,3.0, 1.0, 3.0, 5.0]).

The result should be something like:

Available Predicates

• plot_point/3: plots the points.
• plot_line/3: plots the points and connect them with lines.

How it works

It's simple: the commands are saved in a file named commands.txt. The data are saved in a file named data.temp. Then gnuplot is called passing those two files.

How to test without using pack_install/1

To use the program without downloading the package with pack_install/1 you can do:

• Find the file <SWI-Prolog.h>. Usually is /usr/local/lib/swipl/include/ or /usr/lib/swi-prolog/include/.
• Generate the .o file with gcc passing the location of <SWI-Prolog.h>. If it's in /usr/local/lib/swipl/include/ then the command is:
  • gcc -I/usr/local/lib/swipl/include/ -fpic -c plplot.c
• Generate the .so file with:
  • gcc -shared -o plplot.so plplot.o
• Now you can create a file test.pl like this:

:- load_foreign_library(plplot).

test_p:-
    plot_point('Title',[1.0, 2.0, 3.0, 4.0, 5.0],[5.0 ,3.0, 1.0, 3.0, 5.0]).

• To test use:

    $ swipl test.pl

    ?- test_p.

Contribute and suggestions

Pull requests, issues or whatever you prefer.