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

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

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

=head1 NAME

    Algorithm::Evolutionary::Fitness::Knapsack - Fitness function for the knapsack problem

=head1 SYNOPSIS

    my $n_max=100;  #Max. number of elements to choose
    my $capacity=286; #Max. Capacity of the knapsack
    my $rho=5.0625; #Penalty coeficient
    my @profits = qw( 1..100 );
    my @weights = qw( 2.. 101 );

    my $knapsack = Algorithm::Evolutionary::Fitness::Knapsack->new( $n_max, $capacity, $rho, \@profits, \@weights ); 

=head1 DESCRIPTION

    Knapsack function with penalties applied in a particular way.

=head1 METHODS

=cut

package Algorithm::Evolutionary::Fitness::Knapsack;

our ($VERSION) = ( '$Revision: 3.1 $ ' =~ / (\d+\.\d+)/ ) ;

use Carp qw( croak );
use base qw(Algorithm::Evolutionary::Fitness::String);

=head2 new

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

=cut 

sub new {
  my $class = shift;
  my ( $n_max, $capacity, $rho, $profits_ref, $weights_ref ) = @_;

   if ( ((scalar @$profits_ref) != $n_max ) ||
	((scalar @$weights_ref) != $n_max ) ) {
     croak "Wrong number of profits";
   }

   if ( (scalar @$profits_ref) != ( scalar @$weights_ref ) ) {
     croak "Profits and weights differ";
   }

  #Instantiate superclass
  my $self = $class->SUPER::new();
  
  $self->{'capacity'} = $capacity;
  $self->{ 'rho' }  = $rho;
  $self->{ 'profits'} = $profits_ref;
  $self->{ 'weights'} = $weights_ref;

  $self->initialize();
  return $self;
}