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lib/Algorithm/Evolutionary/Op/Generation_Skeleton.pm  view on Meta::CPAN

=head2 set( $ref_to_params_hash, $ref_to_code_hash, $ref_to_operators_hash )

Sets the instance variables. Takes a ref-to-hash as
input. Not intended to be used from outside the class

=cut

sub set {
  my $self = shift;
  my $hashref = shift || croak "No params here";
  my $codehash = shift || croak "No code here";
  my $opshash = shift || croak "No ops here";

  for ( keys %$codehash ) {
	$self->{"_$_"} =  eval "sub { $codehash->{$_} } ";
  }

  $self->{_ops} =();
  for ( keys %$opshash ) {
    push @{$self->{_ops}}, 
      Algorithm::Evolutionary::Op::Base::fromXML( $_, $opshash->{$_}->[1], $opshash->{$_}->[0] ) ;
  }
}

=head2 apply( $population )

Applies the algorithm to the population, which should have
been evaluated first; checks that it receives a
ref-to-array as input, croaks if it does not. Returns a sorted,
culled, evaluated population for next generation.

=cut

sub apply ($) {
    my $self = shift;
    my $pop = shift || croak "No population here";
    croak "Incorrect type ".(ref $pop) if  ref( $pop ) ne $APPLIESTO;

    #Breed
    my $selector = $self->{'_selector'};
    my @genitors = $selector->apply( @$pop );

    #Reproduce
    my $totRate = 0;
    my @rates;
    my @ops = @{$self->{'_ops'}};
    for ( @ops ) {
	push( @rates, $_->{'rate'});
    }
    my $opWheel = new Algorithm::Evolutionary::Wheel @rates;

    my @newpop;
    my $pringaos =  @$pop  * $self->{'_replacementRate'} ;
    for ( my $i = 0; $i < $pringaos; $i++ ) {
	my @offspring;
	my $selectedOp = $ops[ $opWheel->spin()];
#	  print $selectedOp->asXML;
	for ( my $j = 0; $j < $selectedOp->arity(); $j ++ ) {
	    my $chosen = $genitors[ rand( @genitors )];
#		print "Elegido ", $chosen->asString(), "\n";
	    push( @offspring, $chosen->clone() );
	}
	my $mutante = $selectedOp->apply( @offspring );
	push( @newpop, $mutante );
    }
    
    my $eval = $self->{'_eval'};
    map( $_->evaluate( $eval), @newpop );

    #Eliminate and substitute
    my $pop_hash = $self->{'_replacement_op'}->apply( $pop, \@newpop );
    @$pop = rnkeysort { $_->{'_fitness'} } @$pop_hash ;    
}

=head1 SEE ALSO

More or less in the same ballpark, alternatives to this one

=over 4

=item * 

L<Algorithm::Evolutionary::Op::GeneralGeneration>

=back

=head1 Copyright
  
This file is released under the GPL. See the LICENSE file included in this distribution,
or go to http://www.fsf.org/licenses/gpl.txt

=cut

"The truth is out there";