##
table of contents

Graph::BitMatrix(3) | User Contributed Perl Documentation | Graph::BitMatrix(3) |

# 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.

2024-07-01 | perl v5.40.0 |