1use strict; #-*-cperl-*-
2use warnings;
3
4=head1 NAME
5
6Algorithm::Evolutionary::Op::GenerationalTerm  - Checks for termination of an algorithm.
7
8=head1 SYNOPSIS
9
10  my $gt = new Algorithm::Evolutionary::Op::GenerationalTerm 100; #apply will return false after 100 generations
11
12=head1 Base Class
13
14L<Algorithm::Evolutionary::Op::Base|Algorithm::Evolutionary::Op::Base>
15
16=head1 DESCRIPTION
17
18Checks for termination after a number of generations
19
20=head1 METHODS
21
22=cut
23
24package Algorithm::Evolutionary::Op::GenerationalTerm;
25
26our ($VERSION) = ( '$Revision: 3.0 $ ' =~ / (\d+\.\d+)/ ) ;
27
28use base 'Algorithm::Evolutionary::Op::Base';
29
30=head2 new( [$number_of_generations = 100] )
31
32Creates a new generational terminator:
33
34    my $gt = new Algorithm::Evolutionary::Op::GenerationalTerm 100; #apply will return false after 100 generations
35
36will make the C<apply> method return false after 100 calls
37
38=cut
39
40sub new {
41  my $class = shift;
42  my $hash = { generations => shift || 100,
43	       counter => 0 };
44  my $self = Algorithm::Evolutionary::Op::Base::new( __PACKAGE__, 1, $hash );
45  return $self;
46}
47
48=head2 reset
49
50Resets the number of generations to 0
51
52=cut
53
54sub reset {
55  my $self = shift;
56  $self->{'counter'} =0;
57}
58
59
60=head2 apply()
61
62Checks if the counter has arrived to the allotted number of generations,
63returns false when it does.
64
65    $gt->apply();
66
67will return C<false> when it has been run for the number of times it has
68been initialized to
69
70=cut
71
72sub apply ($) {
73  my $self = shift;
74  $self->{_counter}++;
75  return $self->{_counter} <= $self->{_generations};
76
77}
78
79=head1 See Also
80
81L<Algorithm::Evolutionary::Op::FullAlgorithm> needs an object of this class to check
82for the termination condition. It's normally used alongside "generation-type"
83objects such as L<Algorithm::Evolutionary::Op::Easy>
84
85There are other options for termination conditions: L<Algorithm::Evolutionary::Op::NoChangeTerm|Algorithm::Evolutionary::Op::NoChangeTerm>,  L<Algorithm::Evolutionary::Op::Convergence_Terminator> and L<Algorithm::Evolutionary::Op::DeltaTerm>.
86
87
88=head1 Copyright
89
90  This file is released under the GPL. See the LICENSE file included in this distribution,
91  or go to http://www.fsf.org/licenses/gpl.txt
92
93  CVS Info: $Date: 2009/07/24 08:46:59 $
94  $Header: /media/Backup/Repos/opeal/opeal/Algorithm-Evolutionary/lib/Algorithm/Evolutionary/Op/GenerationalTerm.pm,v 3.0 2009/07/24 08:46:59 jmerelo Exp $
95  $Author: jmerelo $
96  $Revision: 3.0 $
97  $Name $
98
99=cut
100
101"The truth is out there";
102