NAME

       Graph::AdjacencyMatrix - create and query the adjacency matrix of graph G

SYNOPSIS

           use Graph::AdjacencyMatrix;
           use Graph::Directed; # or Undirected

           my $g  = Graph::Directed->new;
           $g->add_...(); # build $g

           my $am = Graph::AdjacencyMatrix->new($g);
           $am->is_adjacent($u, $v)

           my $am = Graph::AdjacencyMatrix->new($g, distance_matrix => 1);
           $am->distance($u, $v)

           my $am = Graph::AdjacencyMatrix->new($g, attribute_name => 'length');
           $am->distance($u, $v)

           my $am = Graph::AdjacencyMatrix->new($g, ...);
           my @V  = $am->vertices();

DESCRIPTION

       You can use "Graph::AdjacencyMatrix" to compute the adjacency matrix and optionally also
       the distance matrix of a graph, and after that query the adjacencyness between vertices by
       using the "is_adjacent()" method, or query the distance between vertices by using the
       "distance()" method.

       By default the edge attribute used for distance is "w", but you can change that in new(),
       see below.

       If you modify the graph after creating the adjacency matrix of it, the adjacency matrix
       and the distance matrix may become invalid.

Methods

   Class Methods
       new($g)
           Construct the adjacency matrix of the graph $g.

       new($g, options)
           Construct the adjacency matrix of the graph $g with options as a hash.  The known
           options are

           distance_matrix => boolean
                   By default only the adjacency matrix is computed.  To compute also the
                   distance matrix, use the attribute "distance_matrix" with a true value to the
                   new() constructor.

           attribute_name => attribute_name
                   By default the edge attribute used for distance is "w".  You can change that
                   by giving another attribute name with the "attribute_name" attribute to new()
                   constructor.  Using this attribute also implicitly causes the distance matrix
                   to be computed.

   Object Methods
       is_adjacent($u, $v)
           Return true if the vertex $v is adjacent to vertex $u, or false if not.

       distance($u, $v)
           Return the distance between the vertices $u and $v, or "undef" if the vertices are not
           adjacent.

       adjacency_matrix
           Return the adjacency matrix itself (a list of bitvector scalars).

       vertices
           Return the list of vertices (useful for indexing the adjacency matrix).

ALGORITHM

       The algorithm used to create the matrix is two nested loops, which is O(V**2) in time, and
       the returned matrices are O(V**2) in space.

SEE ALSO

       Graph::TransitiveClosure, Graph::BitMatrix

AUTHOR AND COPYRIGHT

       Jarkko Hietaniemi jhi@iki.fi

LICENSE

       This module is licensed under the same terms as Perl itself.