NAME

Set::Similarity::Cosine - Cosine similarity for sets

SYNOPSIS

 use Set::Similarity::CosinePP;
 
 # object method
 my $cosine = Set::Similarity::CosinePP->new;
 my $similarity = $cosine->similarity('Photographer','Fotograf');
 
 # class method
 my $cosine = 'Set::Similarity::CosinePP';
 my $similarity = $cosine->similarity('Photographer','Fotograf');
 
 # from 2-grams
 my $width = 2;
 my $similarity = $cosine->similarity('Photographer','Fotograf',$width);
 
 # from arrayref of tokens
 my $similarity = $cosine->similarity(['a','b'],['b']);
 
 # from hashref of features
 my $bird = {
   wings    => true,
   eyes     => true,
   feathers => true,
   hairs    => false,
   legs     => true,
   arms     => false,
 };
 my $mammal = {
   wings    => false,
   eyes     => true,
   feathers => false,
   hairs    => true,
   legs     => true,
   arms     => true, 
 };
 my $similarity = $cosine->similarity($bird,$mammal);
 
 # from arrayref sets
 my $bird = [qw(
   wings
   eyes
   feathers
   legs
 )];
 my $mammal = [qw(
   eyes
   hairs
   legs
   arms
 )];
 my $similarity = $cosine->from_sets($bird,$mammal);

DESCRIPTION

Cosine similarity

A intersection B / (sqrt(A) * sqrt(B))

METHODS

Set::Similarity::CosinePP inherits all methods from Set::Similarity and implements the following new ones.

from_sets

  my $similarity = $object->from_sets(['a'],['b']);
 

This method expects two arrayrefs of strings as parameters. The parameters are not checked, thus can lead to funny results or uncatched divisions by zero.

If you want to use this method directly, you should take care that the elements are unique. Also you should catch the situation where one of the arrayrefs is empty (similarity is 0), or both are empty (similarity is 1).

SOURCE REPOSITORY

http://github.com/wollmers/Set-Similarity-CosinePP

AUTHOR

Helmut Wollmersdorfer, <helmut.wollmersdorfer@gmail.com>

COPYRIGHT AND LICENSE

Copyright (C) 2013-2014 by Helmut Wollmersdorfer

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