NAME "Text::Categorize::Textrank" - Method to rank potential keywords of text. SYNOPSIS use strict; use warnings; use Text::Categorize::Textrank; use Data::Dump qw(dump); my $listOfTokens = [ [qw(This is the first sentence)], [qw(Here is the second sentence)] ]; my $hashOfTextrankValues = getTextrankOfListOfTokens(listOfTokens => $listOfTokens); dump $hashOfTextrankValues; DESCRIPTION "Text::Categorize::Textrank" provides a routine for ranking the words in text as potential keywords. It implements a version of the textrank algorithm from the report *TextRank: Bringing Order into Texts* by R. Mihalcea and P. Tarau. ROUTINES "getTextrankOfListOfTokens" The routine "getTextrankOfListOfTokens" returns a hash reference containing the textrank value for all the tokens in the lists provided; the textrank values sum to one. The textrank of a token is its pagerank in the graph obtained by joining neighboring tokens with an edge, called the token graph. Usually, "listOfTokens" should *not* be applied to all the words of the text. The complete textrank algorithm first filters the words in the text to only the nouns and adjectives. See Text::Categorize::Textrank::En to compute the textrank of English text. "listOfTokens" listOfTokens => [[...], [...], ...[...]] "listOfTokens" is an array reference containing the list of tokens that are to be ranked using textrank. Each list is also an array reference of tokens that should correspond to the list of tokens in a sentence. For example, "[[qw(This is the first sentence)], [qw(Here is the second sentence)]]". "edgeCreationSpan" edgeCreationSpan => 1 For each token in the "listOfTokens", "edgeCreationSpan" is the number of successive tokens used to make an edge in the token graph. For example, if "edgeCreationSpan" is two, then given the token sequence "apple orange pear" the edges "[apple, orange]" and "[apple, pear]" will be added to the token graph for the token "apple". The default is one. Note that loop edges are ignored. For example, if "edgeCreationSpan" is two, then given the token sequence "daba daba doo" the edge "[daba, daba]" is disguarded but the edge "[daba, doo]" is added to the token graph. "directedGraph" directedGraph => 0 If "directedGraph" is true, the textranks are computed from the directed token graph, if false, they are computed from the undirected version of the graph. The default is false. "dampeningFactor" dampeningFactor => 0.85 When computing the textranks of the token graph, the dampening factor specified by "dampeningFactor" will be used; it should range from zero to one. The default is 0.85. "addEdgesSpanningLists" addEdgesSpanningLists => 1 If "addEdgesSpanningLists" is true, then when building the token graph, links between the tokens at the end of a list and the beginning of the next list will be made. For example, for the lists "[[qw(This is the first list)], [qw(Here is the second list)]]" the edge "[list, Here]" will be added to the token graph. The default is true. "tokenWeights" tokenWeights => {} "tokenWeights" is an optional hash reference that can provide a weight for a subset of the tokens provided by "listOfTokens". If "tokenWeights" is not defined for any token in "listOfTokens", then each token has a weight of one. If "tokenWeights" is defined for at least one node in the graph, then the default weight of any undefined token is zero. INSTALLATION To install the module run the following commands: perl Makefile.PL make make test make install If you are on a windows box you should use 'nmake' rather than 'make'. BUGS Please email bugs reports or feature requests to "bug-text-categorize-textrank@rt.cpan.org", or through the web interface at . The author will be notified and you can be automatically notified of progress on the bug fix or feature request. AUTHOR Jeff Kubina COPYRIGHT Copyright (c) 2009 Jeff Kubina. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module. KEYWORDS categorize, keywords, keyphrases, nlp, pagerank, textrank SEE ALSO Graph, Graph::Centrality::Pagerank, Log::Log4perl, Text::Categorize::Textrank::En