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GOBLIN Graph Library 2.8b22 (Default branch)
05-08-2008
The GOBLIN project consists of a C++ class libraryfor a large series of graph optimization problems,GOSH, an extension of the Tcl/Tk scriptinglanguage to graph objects, and GOBLET, a graphicaluser interface to the library functions. GOBLETincludes a graph editor and supports the standardgraph layout methods.License: GNU Lesser General Public License (LGPL)Changes:|
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Graph::TransitiveClosure(3pm) User Contributed Perl Documentation Graph::TransitiveClosure(3pm) Graph::TransitiveClosure - create and query transitive closure of graph SYNOPSIS
use Graph::TransitiveClosure; use Graph::Directed; # or Undirected my $g = Graph::Directed->new; $g->add_...(); # build $g # Compute the transitive closure graph. my $tcg = Graph::TransitiveClosure->new($g); $tcg->is_reachable($u, $v) # Identical to $tcg->has_edge($u, $v) # Being reflexive is the default, meaning that null transitions # (transitions from a vertex to the same vertex) are included. my $tcg = Graph::TransitiveClosure->new($g, reflexive => 1); my $tcg = Graph::TransitiveClosure->new($g, reflexive => 0); # is_reachable(u, v) is always reflexive. $tcg->is_reachable($u, $v) # The reflexivity of is_transitive(u, v) depends of the reflexivity # of the transitive closure. $tcg->is_transitive($u, $v) # You can check any graph for transitivity. $g->is_transitive() my $tcg = Graph::TransitiveClosure->new($g, path_length => 1); $tcg->path_length($u, $v) # path_vertices is automatically always on so this is a no-op. my $tcg = Graph::TransitiveClosure->new($g, path_vertices => 1); $tcg->path_vertices($u, $v) # Both path_length and path_vertices. my $tcg = Graph::TransitiveClosure->new($g, path => 1); $tcg->path_vertices($u, $v) $tcg->length($u, $v) my $tcg = Graph::TransitiveClosure->new($g, attribute_name => 'length'); $tcg->path_length($u, $v) DESCRIPTION
You can use "Graph::TransitiveClosure" to compute the transitive closure graph of a graph and optionally also the minimum paths (lengths and vertices) between vertices, and after that query the transitiveness between vertices by using the "is_reachable()" and "is_transitive()" methods, and the paths by using the "path_length()" and "path_vertices()" methods. For further documentation, see the Graph::TransitiveClosure::Matrix. Class Methods new($g, %opt) Construct a new transitive closure object. Note that strictly speaking the returned object is not a graph; it is a graph plus other stuff. But you should be able to use it as a graph plus a couple of methods inherited from the Graph::TransitiveClosure::Matrix class. Object Methods These are only the methods 'native' to the class: see Graph::TransitiveClosure::Matrix for more. is_transitive($g) Return true if the Graph $g is transitive. transitive_closure_matrix Return the transitive closure matrix of the transitive closure object. INTERNALS The transitive closure matrix is stored as an attribute of the graph called "_tcm", and any methods not found in the graph class are searched in the transitive closure matrix class. perl v5.10.0 2009-01-17 Graph::TransitiveClosure(3pm)