AI-Genetic-Pro
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NAME
AI::Genetic::Pro - Efficient genetic algorithms for professional
purpose with support for multiprocessing.
SYNOPSIS
use AI::Genetic::Pro;
sub fitness {
my ($ga, $chromosome) = @_;
return oct('0b' . $ga->as_string($chromosome));
}
sub terminate {
my ($ga) = @_;
my $result = oct('0b' . $ga->as_string($ga->getFittest));
return $result == 4294967295 ? 1 : 0;
}
my $ga = AI::Genetic::Pro->new(
-fitness => \&fitness, # fitness function
-terminate => \&terminate, # terminate function
-type => 'bitvector', # type of chromosomes
-population => 1000, # population
-crossover => 0.9, # probab. of crossover
-mutation => 0.01, # probab. of mutation
-parents => 2, # number of parents
-selection => [ 'Roulette' ], # selection strategy
-strategy => [ 'Points', 2 ], # crossover strategy
-cache => 0, # cache results
-history => 1, # remember best results
-preserve => 3, # remember the bests
-variable_length => 1, # turn variable length ON
-mce => 1, # optional MCE support
-workers => 3, # number of workers (MCE)
);
# init population of 32-bit vectors
$ga->init(32);
# evolve 10 generations
$ga->evolve(10);
# best score
print "SCORE: ", $ga->as_value($ga->getFittest), ".\n";
# save evolution path as a chart
$ga->chart(-filename => 'evolution.png');
# save state of GA
$ga->save('genetic.sga');
# load state of GA
$ga->load('genetic.sga');
DESCRIPTION
This module provides efficient implementation of a genetic algorithm
for professional purpose with support for multiprocessing. It was
designed to operate as fast as possible even on very large populations
and big individuals/chromosomes. AI::Genetic::Pro was inspired by
AI::Genetic, so it is in most cases compatible (there are some
changes). Additionally AI::Genetic::Pro isn't a pure Perl solution, so
it doesn't have limitations of its ancestor (such as slow-down in the
case of big populations ( >10000 ) or vectors with more than 33
fields).
If You are looking for a pure Perl solution, consider AI::Genetic.
Speed
To increase speed XS code is used, however with portability in mind.
This distribution was tested on Windows and Linux platforms (and
should work on any other).
Multicore support is available through Many-Core Engine (MCE). You
can gain the most speed up for big populations or time/CPU consuming
fitness functions, however for small populations and/or simple
fitness function better choice will be single-process version.
You can get even more speed up if you turn on use of native arrays
(parameter: native) instead of packing chromosomes into single
scalar. However you have to remember about expensive memory use in
that case.
Memory
This module was designed to use as little memory as possible. A
population of size 10000 consisting of 92-bit vectors uses only ~24MB
(AI::Genetic would use about 78MB). However - if you use MCE - there
will be bigger memory consumption. This is consequence of necessity
of synchronization between many processes.
Advanced options
To provide more flexibility AI::Genetic::Pro supports many
statistical distributions, such as uniform, natural, chi_square and
others. This feature can be used in selection and/or crossover. See
the documentation below.
METHODS
$ga->new( %options )
Constructor. It accepts options in hash-value style. See options and
returned and if the returned chromosomes should be unique. See
example below.
# only one - the best
my ($best) = $ga->getFittest;
# or 5 bests chromosomes, NOT unique
my @bests = $ga->getFittest(5);
# or 7 bests and UNIQUE chromosomes
my @bests = $ga->getFittest(7, 1);
If you want to get a large number of chromosomes, try to use the
getFittest_as_arrayref function instead (for efficiency).
$ga->getFittest_as_arrayref($n, $unique)
This function is very similar to getFittest, but it returns a
reference to an array instead of a list.
$ga->generation()
Get the number of the current generation.
$ga->people()
Returns an anonymous list of individuals/chromosomes of the current
population.
IMPORTANT: the actual array reference used by the AI::Genetic::Pro
object is returned, so any changes to it will be reflected in $ga.
$ga->chromosomes()
Alias for people.
$ga->chart(%options)
Generate a chart describing changes of min, mean, and max scores in
your population. To satisfy your needs, you can pass the following
options:
-filename
File to save a chart in (obligatory).
-title
Title of a chart (default: Evolution).
-x_label
X label (default: Generations).
-y_label
Y label (default: Value).
-format
Format of values, like sprintf (default: '%.2f').
-legend1
Description of min line (default: Min value).
-legend2
Description of min line (default: Mean value).
-legend3
Description of min line (default: Max value).
-width
Width of a chart (default: 640).
-height
Height of a chart (default: 480).
-font
Path to font (in *.ttf format) to be used (default: none).
-logo
Path to logo (png/jpg image) to embed in a chart (default: none).
For example:
$ga->chart(-width => 480, height => 320, -filename => 'chart.png');
$ga->save($file)
Save the current state of the genetic algorithm to the specified
file.
$ga->load($file)
Load a state of the genetic algorithm from the specified file.
$ga->as_array($chromosome)
In list context return an array representing the specified
chromosome. In scalar context return an reference to an array
representing the specified chromosome. If variable_length is turned
on and is set to level 2, an array can have some undef values. To get
only not undef values use as_array_def_only instead of as_array.
$ga->as_array_def_only($chromosome)
In list context return an array representing the specified
chromosome. In scalar context return an reference to an array
representing the specified chromosome. If variable_length is turned
off, this function is just an alias for as_array. If variable_length
is turned on and is set to level 2, this function will return only
not undef values from chromosome. See example below:
# -variable_length => 2, -type => 'bitvector'
( run in 1.000 second using v1.01-cache-2.11-cpan-437f7b0c052 )