graph::unionfind(3pm) [debian man page]

Graph::UnionFind(3pm)					User Contributed Perl Documentation				     Graph::UnionFind(3pm)

NAME

       Graph::UnionFind - union-find data structures

SYNOPSIS

	   use Graph::UnionFind;
	   my $uf = Graph::UnionFind->new;

	   # Add the vertices to the data structure.
	   $uf->add($u);
	   $uf->add($v);

	   # Join the partitions of the vertices.
	   $uf->union( $u, $v );

	   # Find the partitions the vertices belong to
	   # in the union-find data structure.	If they
	   # are equal, they are in the same partition.
	   # If the vertex has not been seen,
	   # undef is returned.
	   my $pu = $uf->find( $u );
	   my $pv = $uf->find( $v );
	   $uf->same($u, $v) # Equal to $pu eq $pv.

	   # Has the union-find seen this vertex?
	   $uf->has( $v )

DESCRIPTION

       Union-find is a special data structure that can be used to track the partitioning of a set into subsets (a problem known also as disjoint
       sets).

       Graph::UnionFind() is used for Graph::connected_components(), Graph::connected_component(), and Graph::same_connected_components() if you
       specify a true "union_find" parameter when you create an undirected graph.

       Note that union-find is one way: you cannot (easily) 'ununion' vertices once you have 'unioned' them.  This means that if you delete edges
       from a "union_find" graph, you will get wrong results from the Graph::connected_components(), Graph::connected_component(), and
       Graph::same_connected_components().

   API
       add
	       $uf->add($v)

	   Add the vertex v to the union-find.

       union
	       $uf->union($u, $v)

	   Add the edge u-v to the union-find.	Also implicitly adds the vertices.

       has
	       $uf->has($v)

	   Return true if the vertex v has been added to the union-find, false otherwise.

       find
	       $uf->find($v)

	   Return the union-find partition the vertex v belongs to, or "undef" if it has not been added.

       new
	       $uf = Graph::UnionFind->new()

	   The constructor.

       same
	       $uf->same($u, $v)

	   Return true of the vertices belong to the same union-find partition the vertex v belongs to, false otherwise.

AUTHOR AND COPYRIGHT

       Jarkko Hietaniemi jhi@iki.fi

LICENSE

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

perl v5.10.0							    2008-11-27						     Graph::UnionFind(3pm)

Check Out this Related Man Page

Graph::Writer::XML(3pm) 				User Contributed Perl Documentation				   Graph::Writer::XML(3pm)

NAME

       Graph::Writer::XML - write out directed graph as XML

SYNOPSIS

	   use Graph;
	   use Graph::Writer::XML;

	   $graph = Graph->new();
	   # add edges and nodes to the graph

	   $writer = Graph::Writer::XML->new();
	   $writer->write_graph($graph, 'mygraph.xml');

DESCRIPTION

       Graph::Writer::XML is a class for writing out a directed graph in a simple XML format.  The graph must be an instance of the Graph class,
       which is actually a set of classes developed by Jarkko Hietaniemi.

       The XML format is designed to support the Graph classes: it can be used to represent a single graph with a collection of nodes, and edges
       between those nodes.  The graph, nodes, and edges can all have attributes specified, where an attribute is a (name,value) pair, with the
       value being scalar.

METHODS

   new()
       Constructor - generate a new writer instance.

	   $writer = Graph::Writer::XML->new();

       This doesn't take any arguments.

   write_graph()
       Write a specific graph to a named file:

	   $writer->write_graph($graph, $file);

       The $file argument can either be a filename, or a filehandle for a previously opened file.

KNOWN BUGS

       Attribute values must be scalar. If they're not, well, you're on your own.

SEE ALSO

       XML::Writer
	   The perl module used to actually write out the XML.	It handles entities etc.

       Graph
	   Jarkko Hietaniemi's modules for representing directed graphs, available from CPAN under modules/by-module/Graph/

       Algorithms in Perl
	   The O'Reilly book which has a chapter on directed graphs, which is based around Jarkko's modules.

       Graph::Writer
	   The base-class for Graph::Writer::XML

AUTHOR

       Neil Bowers <neil@bowers.com>

COPYRIGHT

       Copyright (c) 2001-2012, Neil Bowers. All rights reserved.  Copyright (c) 2001, Canon Research Centre Europe. All rights reserved.

       This script is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.14.2							    2012-02-14						   Graph::Writer::XML(3pm)

Linux and UNIX Man Pages

graph::unionfind(3pm) [debian man page]

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