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lib/Algorithm/Evolutionary/Fitness/ECC.pm  view on Meta::CPAN

use strict; # -*- cperl -*-
use warnings;

use lib qw( ../../../../lib );

=head1 NAME

Algorithm::Evolutionary::Fitness::ECC - Error Correcting codes problem generator

=head1 SYNOPSIS

    my $number_of_codewords = 10;
    my $min_distance = 1;
    my $p_peaks = Algorithm::Evolutionary::Fitness::ECC->new( $number_of_codewords, $min_distance );

=head1 DESCRIPTION

Extracted from article "Effects of scale-free and small-world topologies on binary coded self-adaptive CEA", by Giacobini et al [Ga]. Quoting:
"                                                    The ECC problem was presented in
[MW]. We will consider a three-tuple (n, M, d), where n is the length of each codeword
(number of bits), M is the number of codewords, and d is the minimum Hamming
distance between any pair of codewords. Our objective will be to find a code which
has a value for d as large as possible (reflecting greater tolerance to noise and errors),
given previously fixed values for n and M . The problem we have studied is a simplified
version of that in [MW]. In our case we search half of the codewords (M/2) that will
compose the code, and the other half is made up by the complement of the codewords
computed by the algorithm"

[Ga] Mario Giacobini, Mike Preuss, Marco Tomassini: Effects of Scale-Free and Small-World Topologies on Binary Coded Self-adaptive CEA. EvoCOP 2006: 86-98.

[MW] F. J. MacWilliams and N. J. A. Sloane. The Theory of Error-Correcting Codes. North-
    Holland, Amsterdam, 1977.


=head1 METHODS

=cut

package Algorithm::Evolutionary::Fitness::ECC;

our ($VERSION) = ( '$Revision: 3.2 $ ' =~ / (\d+\.\d+)/ ) ;

use Carp qw(croak);

use lib qw(../../.. ../.. ..);

use base qw(Algorithm::Evolutionary::Fitness::String);
use Algorithm::Evolutionary::Utils qw(hamming);

=head2 new

Creates a new instance of the problem, with the said number of bits and peaks

=cut 

sub new {
  my $class = shift;
  my ($number_of_codewords, $min_distance ) = @_;
  croak "Too few codewords" if !$number_of_codewords;
  croak "Distance too small" if !$min_distance;
  my $self = $class->SUPER::new();
  bless $self, $class;
  $self->initialize();
  $self->{'number_of_codewords'} = $number_of_codewords;
  return $self;
}

=head2 _really_apply

Applies the instantiated problem to a chromosome

=cut

sub _really_apply {
  my $self = shift;
  return $self->ecc( @_ );
}

=head2 ecc

Applies the instantiated problem to a string

=cut