GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  GRAPH::TRAVERSAL (3)

.ds Aq ’

NAME

Graph::Traversal - traverse graphs

CONTENTS

SYNOPSIS

Don’t use Graph::Traversal directly, use Graph::Traversal::DFS or Graph::Traversal::BFS instead.



    use Graph;
    my $g = Graph->new;
    $g->add_edge(...);
    use Graph::Traversal::...;
    my $t = Graph::Traversal::...->new($g, %opt);
    $t->...



DESCRIPTION

You can control how the graph is traversed by the various callback parameters in the %opt. In the parameters descriptions below the $u and $v are vertices, and the $self is the traversal object itself.

    Callback parameters

The following callback parameters are available:
tree_edge Called when traversing an edge that belongs to the traversal tree. Called with arguments ($u, $v, $self).
non_tree_edge Called when an edge is met which either leads back to the traversal tree (either a back_edge, a down_edge, or a cross_edge). Called with arguments ($u, $v, $self).
pre_edge Called for edges in preorder. Called with arguments ($u, $v, $self).
post_edge Called for edges in postorder. Called with arguments ($u, $v, $self).
back_edge Called for back edges. Called with arguments ($u, $v, $self).
down_edge Called for down edges. Called with arguments ($u, $v, $self).
cross_edge Called for cross edges. Called with arguments ($u, $v, $self).
pre
pre_vertex Called for vertices in preorder. Called with arguments ($v, $self).
post
post_vertex Called for vertices in postorder. Called with arguments ($v, $self).
first_root Called when choosing the first root (start) vertex for traversal. Called with arguments ($self, $unseen) where $unseen is a hash reference with the unseen vertices as keys.
next_root Called when choosing the next root (after the first one) vertex for traversal (useful when the graph is not connected). Called with arguments ($self, $unseen) where $unseen is a hash reference with the unseen vertices as keys. If you want only the first reachable subgraph to be processed, set the next_root to undef.
start Identical to defining first_root and undefining next_root.
next_alphabetic Set this to true if you want the vertices to be processed in alphabetic order (and leave first_root/next_root undefined).
next_numeric Set this to true if you want the vertices to be processed in numeric order (and leave first_root/next_root undefined).
next_successor Called when choosing the next vertex to visit. Called with arguments ($self, $next) where $next is a hash reference with the possible next vertices as keys. Use this to provide a custom ordering for choosing vertices, as opposed to next_numeric or next_alphabetic.
The parameters first_root and next_successor have a ’hierarchy’ of how they are determined: if they have been explicitly defined, use that value. If not, use the value of next_alphabetic, if that has been defined. If not, use the value of next_numeric, if that has been defined. If not, the next vertex to be visited is chose randomly.

    Methods

The following methods are available:
unseen Return the unseen vertices in random order.
seen Return the seen vertices in random order.
seeing Return the active fringe vertices in random order.
preorder Return the vertices in preorder traversal order.
postorder Return the vertices in postorder traversal order.
vertex_by_preorder


    $v = $t->vertex_by_preorder($i)



Return the ith (0..$V-1) vertex by preorder.

preorder_by_vertex


    $i = $t->preorder_by_vertex($v)



Return the preorder index (0..$V-1) by vertex.

vertex_by_postorder


    $v = $t->vertex_by_postorder($i)



Return the ith (0..$V-1) vertex by postorder.

postorder_by_vertex


    $i = $t->postorder_by_vertex($v)



Return the postorder index (0..$V-1) by vertex.

preorder_vertices Return a hash with the vertices as the keys and their preorder indices as the values.
postorder_vertices Return a hash with the vertices as the keys and their postorder indices as the values.
tree Return the traversal tree as a graph.
has_state


    $t->has_state(s)



Test whether the traversal has state ’s’ attached to it.

get_state


    $t->get_state(s)



Get the state ’s’ attached to the traversal (undef if none).

set_state


    $t->set_state(s, $s)



Set the state ’s’ attached to the traversal.

delete_state


    $t->delete_state(s)



Delete the state ’s’ from the traversal.

    Backward compatibility

The following parameters are for backward compatibility to Graph 0.2xx:
get_next_root Like next_root.
successor Identical to having tree_edge both non_tree_edge defined to be the same.
unseen_successor Like tree_edge.
seen_successor Like seed_edge.

    Special callbacks

If in a callback you call the special terminate method, the traversal is terminated, no more vertices are traversed.

SEE ALSO

Graph::Traversal::DFS, Graph::Traversal::BFS

AUTHOR AND COPYRIGHT

Jarkko Hietaniemi jhi@iki.fi

LICENSE

This module is licensed under the same terms as Perl itself.
Search for    or go to Top of page |  Section 3 |  Main Index


perl v5.20.3 GRAPH::TRAVERSAL (3) 2013-05-24

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.