NAME
    Set::Similarity - similarity measures for sets

SYNOPSIS
     use Set::Similarity::Dice;
 
     # object method
     my $dice = Set::Similarity::Dice->new;
     my $similarity = $dice->similarity('Photographer','Fotograf');
 
     # class method
     my $dice = 'Set::Similarity::Dice';
     my $similarity = $dice->similarity('Photographer','Fotograf');
 
     # from 2-grams
     my $width = 2;
     my $similarity = $dice->similarity('Photographer','Fotograf',$width);
 
     # from arrayref of tokens
     my $similarity = $dice->similarity(['a','b'],['b']);
 
     # from hashref of features
 
     # from hashref sets

DESCRIPTION
  Overlap coefficient
    ( A intersect B ) / min(A,B)

  Jaccard Index
    The Jaccard coefficient measures similarity between sample sets, and is
    defined as the size of the intersection divided by the size of the union
    of the sample sets

    ( A intersect B ) / (A union B)

    The Tanimoto coefficient is the ratio of the number of features common
    to both molecules to the total number of features, i.e.

    ( A intersect B ) / ( A + B - ( A intersect B ) ) # the same as Jaccard

    The range is 0 to 1 inclusive.

  Dice coefficient
    The Dice coefficient is the number of features in common to both
    molecules relative to the average size of the total number of features
    present, i.e.

    ( A intersect B ) / 0.5 ( A + B ) # the same as sorensen

    The weighting factor comes from the 0.5 in the denominator. The range is
    0 to 1.

METHODS
  new
      $object = Set::Similarity->new();

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

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

  from_sets
      my $similarity = $object->from_sets({'a' => undef},{'b' => undef});

  intersection
      my $intersection_size = $object->intersection({'a' => undef},{'b' => undef});

  combined_length
      my $set_size_sum = $object->combined_length({'a' => undef},{'b' => undef});

  min
      my $min_set_size = $object->min({'a' => undef},{'b' => undef});

  ngrams
      my $bigrams = $object->ngrams('abc',2);

SOURCE REPOSITORY
    <http://github.com/wollmers/Set-Similarity>

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

COPYRIGHT AND LICENSE
    Copyright (C) 2013 by Helmut Wollmersdorfer

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