view release on metacpan or  search on metacpan

lib/AI/Evolve/Befunge.pm  view on Meta::CPAN

package AI::Evolve::Befunge;
use strict;
use warnings;

our $VERSION = "0.03";

=head1 NAME

    AI::Evolve::Befunge - practical evolution of Befunge AI programs


=head1 SYNOPSIS

    use aliased 'AI::Evolve::Befunge::Population' => 'Population';
    use AI::Evolve::Befunge::Util qw(v nonquiet);

    $pop = Population->new();

    while(1) {
        my $gen  = $pop->generation;
        nonquiet("generation $gen\n");
        $pop->fight();
        $pop->breed();
        $pop->migrate();
        $pop->save();
        $pop->generation($gen+1);
    }


=head1 DESCRIPTION

This software project provides all of the necessary tools to grow a
population of AI creatures which are fit to perform a task.

Normally, end users can use the "evolve" script as a frontend.  If
that's what you're after, please see the documentation contained
within that script.  Otherwise, read on.

This particular file (AI/Evolve/Befunge.pm) does not contain any code;
it exists mainly to provide a version number to keep Build.PL happy.
The rest of this file acts as a quick-start guide to the rest of the
codebase.

The important bits from a user's standpoint are the Population object
(which drives the main process of evolving AI), and the Physics plugin
(which implements the rules of the universe those AI live in).  There
are sections below containing more detail on what these two things
are, and how they work.


=head1 POPULATIONS

The Population object is the main user interface to this project.
Basically you just keep running it over and over, and presumably, the
result gets better and better.

The important thing to remember here is that the results take time -
it will probably take several weeks of solid processing time before you
begin to see any promising results at all.  It takes a lot of random
code generation before it starts to generate code that does what you
want it to do.

If you don't know anything about Befunge, I recommend you read up on
that first, before trying to understand how this works.

The individuals of this population (which we call Critters) may be of
various sizes, and may make heavy or light use of threads and stacks.
Each one is issued a certain number of "tokens" (which you can think
of as blood sugar or battery power).  Just being born takes a certain
number of tokens, depending on the code size.  After that, doing things
(like executing a befunge command, pushing a value to the stack,
spawning a thread) all take a certain number of tokens to accomplish.
When the number of tokens drops to 0, the critter dies.  So it had
better accomplish its task before that happens.

After a population fights it out for a while, the winners are chosen
(who continue to live) and everyone else dies.  Then a new population
is generated from the winners, some random mutation (random
generation of code, as well as potentially resizing the codebase)
occurs, and the whole process starts over for the next generation.


=head1 PHYSICS

At the other end of all of this is the Physics plugin.  The Physics
plugin implements the rules of the universe inhabited by these AI
creatures.  It provides a scoring mechanism through which multiple