NAME

Algorithm::FeatureSelection -

SYNOPSIS

use Algorithm::FeatureSelection;
my $fs = Algorithm::FeatureSelection->new();

# feature-class data structure ...
my $features = {
  feature_1 => {
      class_a => 10,
      class_b => 2,
  },
  feature_2 => {
      class_b => 11,
      class_d => 32
  },
        .
        .
        .
};

# get pairwise-mutula-information
my $pmi = $fs->pairwise_mutual_information($features);
my $pmi = $fs->pmi($features); # same above

# get information-gain 
my $ig = $fs->information_gain($features);
my $ig = $fs->ig($features); # same above

DESCRIPTION

This library is an perl implementation of 'Pairwaise Mutual Information' and 'Information Gain' that are used as well-known method of feature selection on text mining fields.

METHOD

new()

information_gain( $features )

my $features = {
  feature_1 => {
      class_a => 10,
      class_b => 2,
  },
  feature_2 => {
      class_b => 11,
      class_d => 32
  },
        .
        .
        .
};
my $fs = Algorithm::FeatureSelection->new();
my $ig = $fs->information_gain($features);

ig( $features )

short name of information_gain()

information_gain_ratio( $features )

my $features = {
  feature_1 => {
      class_a => 10,
      class_b => 2,
  },
  feature_2 => {
      class_b => 11,
      class_d => 32
  },
        .
        .
        .
};
my $fs = Algorithm::FeatureSelection->new();
my $igr = $fs->information_gain_ratio($features);

igr( $features )

short name of information_gain_ratio()

pairwise_mutual_information( $features )

my $features = {
  feature_1 => {
      class_a => 10,
      class_b => 2,
  },
  feature_2 => {
      class_b => 11,
      class_d => 32
  },
        .
        .
        .
};
my $fs = Algorithm::FeatureSelection->new();
my $pmi = $fs->pairwise_mutual_information($features);

pmi( $features )

short name of pairwise_mutual_information()

entropy(HASH|ARRAY)

calcurate entropy.

AUTHOR

Takeshi Miki <miki@cpan.org>

SEE ALSO

LICENSE

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