/usr/local/perl/lib/site_perl/5.8.5/Graph/TransitiveClosure.pm |
use Graph::TransitiveClosure; use Graph::Directed; # or Undirected
my $g = Graph::Directed->new; $g->add_...(); # build $g
# Compute the transitive closure graph. my $tcg = Graph::TransitiveClosure->new($g); $tcg->is_reachable($u, $v) # Identical to $tcg->has_edge($u, $v)
# Being reflexive is the default, meaning that null transitions # (transitions from a vertex to the same vertex) are included. my $tcg = Graph::TransitiveClosure->new($g, reflexive => 1); my $tcg = Graph::TransitiveClosure->new($g, reflexive => 0);
# is_reachable(u, v) is always reflexive. $tcg->is_reachable($u, $v)
# The reflexivity of is_transitive(u, v) depends of the reflexivity # of the transitive closure. $tcg->is_transitive($u, $v)
# You can check any graph for transitivity. $g->is_transitive()
my $tcg = Graph::TransitiveClosure->new($g, path_length => 1); $tcg->path_length($u, $v)
# path_vertices is automatically always on so this is a no-op. my $tcg = Graph::TransitiveClosure->new($g, path_vertices => 1); $tcg->path_vertices($u, $v)
# Both path_length and path_vertices. my $tcg = Graph::TransitiveClosure->new($g, path => 1); $tcg->path_vertices($u, $v) $tcg->length($u, $v)
my $tcg = Graph::TransitiveClosure->new($g, attribute_name => 'length'); $tcg->path_length($u, $v)
You can use Graph::TransitiveClosure
to compute the transitive
closure graph of a graph and optionally also the minimum paths
(lengths and vertices) between vertices, and after that query the
transitiveness between vertices by using the is_reachable()
and
is_transitive()
methods, and the paths by using the
path_length()
and path_vertices()
methods.
For further documentation, see the the Graph::TransitiveClosure::Matrix manpage.
These are only the methods 'native' to the class: see the Graph::TransitiveClosure::Matrix manpage for more.
is_transitive($g)
The transitive closure matrix is stored as an attribute of the graph
called _tcm
, and any methods not found in the graph class are searched
in the transitive closure matrix class.
/usr/local/perl/lib/site_perl/5.8.5/Graph/TransitiveClosure.pm |