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package Graph::Maker::Barbell;
use strict;
use warnings;
use Carp qw/croak/;
use base qw/Graph::Maker/;
use Graph;
our $VERSION = '0.01';
sub init
{
my ($self, %params) = @_;
my $n1 = delete($params{N1}) || 0;
my $n2 = delete($params{N2}) || 0;
my $gm = delete($params{graph_maker});
croak "graph_maker must be a reference to a function that creates a Graph.\n" if $gm && ref($gm) ne 'CODE';
$gm ||= sub { new Graph(@_); };
my $g = $gm->(%params);
# Left
for my $u(1..$n1)
{
my $min = $g->is_directed() ? 1 : $u+1;
for my $v($min..$n1)
{
next if $u == $v;
$g->add_edge($u, $v);
}
}
# Bar
$g->add_path($n1..$n1+$n2+1);
$g->add_path(reverse $n1..$n1+$n2+1) if $g->is_directed();
# Right
for my $u(1..$n1)
{
my $min = $g->is_directed() ? 1 : $u+1;
for my $v($min..$n1)
{
next if $u == $v;
$g->add_edge($n1+$n2+$u, $n1+$n2+$v);
}
}
return $g;
}
Graph::Maker->add_factory_type( 'barbell' => __PACKAGE__ );
1;
__DATA__
=head1 NAME
Graph::Maker::Barbell - Create barbell graphs
=head1 VERSION
Version 0.01
=cut
=head1 SYNOPSIS
Creates the barbell graph with N1 nodes on the left, N1 nodes on the right
and N2 nodes in the center bar. A barbell graph is one in which there
are two fully-connected components of size N1 connected by a single bridge
of N2 nodes. If the graph is directed, then edges are added in both directions
to create an undirected graph.
use strict;
use warnings;
use Graph;
use Graph::Maker;
use Graph::Maker::Barbell;
my $g = new Graph::Maker('barbell', N1 => 4, N2 => 2);
# work with the graph
=head1 FUNCTIONS
=head2 new %params
Creates the barbell graph with N1 nodes on the left and right and N2 nodes in the center bar,
The recognized parameters are graph_maker, N1 and N2
any others are passed onto L<Graph>'s constructor.
If N1 is not given it defaults to 0.
If N2 is not given it defaults to 0.
If graph_maker is specified it will be called to create the Graph class as desired (for example if you have a
subclass of Graph), this defaults to create a Graph with the parameters specified.
=cut
=head1 AUTHOR
Matt Spear, C<< <batman900+cpan at gmail.com> >>
=head1 BUGS
None at the moment...
Please report any bugs or feature requests to
C<bug-graph-maker-barbell at rt.cpan.org>, or through the web interface at
L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Graph-Maker>.
I will be notified, and then you'll automatically be notified of progress on
your bug as I make changes.
=head1 COPYRIGHT & LICENSE
Copyright 2008 Matt Spear, all rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
=cut
|
