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: !Screenshot

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.