| CC: | <jhi [...] iki.fi> |
| Subject: | Bugreport: Graph::Undirected, unionfind and connected_components |
| Date: | Thu, 29 Nov 2007 14:03:32 +0100 |
| To: | <bug-Graph [...] rt.cpan.org> |
| From: | "Denis Lagno" <dlagno [...] nvidia.com> |
Hi Jarkko
I detected bug in Graph-0.81 and it reproduces in Graph-0.84
I use perl 5.8.8
If graph is created in unionfind mode it does not correctly handle
adding already existing vertex.
For this test code:
use Graph::Undirected;
sub fill_graph
{
my $graph = shift;
$graph->add_edge('A', 'B');
$graph->add_vertex('A');
}
my $graph1 = Graph::Undirected->new('unionfind' => 1);
fill_graph($graph1);
warn "number of components in unionfind graph is " .
scalar($graph1->connected_components()) . "\n";
my $graph2 = Graph::Undirected->new('unionfind' => 0);
fill_graph($graph2);
warn "number of components in non-unionfind graph is " .
scalar($graph2->connected_components()) . "\n";
It outputs:
number of components in unionfind graph is 2
number of components in non-unionfind graph is 1
I guess it is a bug.
-- denis
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