NAME

       Graph::BitMatrix - create and manipulate a V x V bit matrix of graph G

SYNOPSIS

           use Graph::BitMatrix;
           use Graph::Directed;
           my $g  = Graph::Directed->new;
           $g->add_...(); # build $g
           my $m = Graph::BitMatrix->new($g, %opt);
           $m->get($u, $v)
           $m->set($u, $v)
           $m->unset($u, $v)
           $m->get_row($u, $v1, $v2, ..., $vn)
           $m->set_row($u, $v1, $v2, ..., $vn)
           $m->unset_row($u, $v1, $v2, ..., $vn)
           $a->vertices()

DESCRIPTION

       This class enables creating bit matrices that compactly describe the connected of the graphs.

   Class Methods
       new($g)
           Create a bit matrix from a Graph $g.  The %opt, if present, can have the following options:

           •       connect_edges

                   If true or if not present, set the bits in the bit matrix that correspond to edges.  If
                   false, do not set any bits.  In either case the bit matrix of V x V bits is allocated.

           •       transpose

                   If true, set the bits in the bit matrix that correspond to edges but in the reverse
                   direction. This has the effect of transposing the matrix. Obviously makes no difference to
                   the result for undirected graphs.

   Object Methods
       get($u, $v)
           Return true if the bit matrix has a "one bit" between the vertices $u and $v; in other words, if
           there is (at least one) a vertex going from $u to $v.  If there is no vertex and therefore a "zero
           bit", return false.

       set($u, $v)
           Set the bit between the vertices $u and $v; in other words, connect the vertices $u and $v by an
           edge.  The change does not get mirrored back to the original graph.  Returns nothing.

       unset($u, $v)
           Unset the bit between the vertices $u and $v; in other words, disconnect the vertices $u and $v by an
           edge.  The change does not get mirrored back to the original graph.  Returns nothing.

       get_row($u, $v1, $v2, ..., $vn)
           Test the row at vertex "u" for the vertices "v1", "v2", ..., "vn" Returns a list of n truth values.

       set_row($u, $v1, $v2, ..., $vn)
           Sets the row at vertex "u" for the vertices "v1", "v2", ..., "vn", in other words, connects the
           vertex "u" to the vertices "vi".  The changes do not get mirrored back to the original graph.
           Returns nothing.

       unset_row($u, $v1, $v2, ..., $vn)
           Unsets the row at vertex "u" for the vertices "v1", "v2", ..., "vn", in other words, disconnects the
           vertex "u" from the vertices "vi".  The changes do not get mirrored back to the original graph.
           Returns nothing.

       vertices
           Return the list of vertices in the bit 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.

AUTHOR AND COPYRIGHT

       Jarkko Hietaniemi jhi@iki.fi

LICENSE

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