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Text::NSP::Measures::3D::MI::pmi.3pm
Langue: en
Version: 2006-06-21 (mandriva - 01/05/08)
Section: 3 (Bibliothèques de fonctions)
NAME
Text::NSP::Measures::3D::MI::pmi - Perl module that implements PointwiseMutual Information for trigrams.
SYNOPSIS
Basic Usageuse Text::NSP::Measures::3D::MI::pmi;
$pmi_value = calculateStatistic( n111=>10, n1pp=>40, np1p=>45, npp1=>42, n11p=>20, n1p1=>23, np11=>21, nppp=>100);
if( ($errorCode = getErrorCode())) { print STDERR $erroCode." - ".getErrorMessage()."\n"; } else { print getStatisticName."value for bigram is ".$pmi_value."\n"; }
DESCRIPTION
The expected values for the internal cells are calculated by taking the product of their associated marginals and dividing by the sample size, for example:n1pp * np1p * npp1 m111= -------------------- nppp
Pointwise Mutual Information (pmi) is defined as the log of the devitation between the observed frequency of a trigram (n111) and the probability of that trigram if it were independent (m111).
PMI = log (n111/m111)
Methods
- initializeStatistic() -Initialization of the pmi_exp parameter if required
- INPUT PARAMS : none
RETURN VALUES : none
- calculateStatistic() - This method calculates the pmi value
- INPUT PARAMS : $count_values .. Reference of a hash containing
the count values computed by the
count.pl program.RETURN VALUES : $pmi .. PMI value for this trigram.
- getStatisticName() - Returns the name of this statistic
- INPUT PARAMS : none
RETURN VALUES : $name .. Name of the measure.
AUTHOR
Ted Pedersen, University of Minnesota Duluth<tpederse@d.umn.edu>
Satanjeev Banerjee, Carnegie Mellon University
<satanjeev@cmu.edu>
Amruta Purandare, University of Pittsburgh
<amruta@cs.pitt.edu>
Bridget Thomson-McInnes, University of Minnesota Twin Cities
<bthompson@d.umn.edu>
Saiyam Kohli, University of Minnesota Duluth
<kohli003@d.umn.edu>
HISTORY
Last updated: $Id: pmi.pm,v 1.8 2006/06/21 11:10:53 saiyam_kohli Exp $BUGS
SEE ALSO
@inproceedings{ church89word, author = {Kenneth W. Church and Patrick Hanks}, title = {Word association norms, mutual information, and Lexicography}, booktitle = {Proceedings of the 27th. Annual Meeting of the Association for Computational Linguistics}, publisher = {Association for Computational Linguistics}, address = {Vancouver, B.C.}, pages = {76--83}, year = {1989}, url = L<http://acl.ldc.upenn.edu/J/J90/J90-1003.pdf> }
<http://groups.yahoo.com/group/ngram/>
<http://www.d.umn.edu/~tpederse/nsp.html>
COPYRIGHT
Copyright (C) 2000-2006, Ted Pedersen, Satanjeev Banerjee, Amruta Purandare, Bridget Thomson-McInnes and Saiyam KohliThis program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to
The Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Note: a copy of the GNU General Public License is available on the web at <http://www.gnu.org/licenses/gpl.txt> and is included in this distribution as GPL.txt.
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre