Class: FSelector::OddsRatio

Inherits:
BaseDiscrete show all
Defined in:
lib/fselector/algo_discrete/OddsRatio.rb

Overview

Odds Ratio (Odd)

           P(f|c) * (1 - P(f|c'))     tpr * (1-fpr)
Odd(f,c) = ----------------------- = ---------------
           (1 - P(f|c)) * P(f|c')     (1-tpr) * fpr

            A*D
         = -----
            B*C

ref: Wikipedia and An extensive empirical study of feature selection metrics for text classification and Optimally Combining Positive and Negative Features for Text Categorization

Method Summary

Methods inherited from BaseDiscrete

#initialize

Methods included from Discretizer

#discretize_by_Chi2!, #discretize_by_ChiMerge!, #discretize_by_MID!, #discretize_by_TID!, #discretize_by_equal_frequency!, #discretize_by_equal_width!

Methods included from Entropy

#get_conditional_entropy, #get_information_gain, #get_joint_entropy, #get_marginal_entropy, #get_symmetrical_uncertainty

Methods included from Consistency

#get_IR, #get_IR_by_count, #get_IR_by_feature, #get_instance_count

Methods inherited from Base

#algo_type, #each_class, #each_feature, #each_sample, #get_class_labels, #get_classes, #get_data, #get_data_copy, #get_feature_ranks, #get_feature_scores, #get_feature_type, #get_feature_values, #get_features, #get_opt, #get_sample_size, #initialize, #select_feature!, #select_feature_by_rank!, #select_feature_by_score!, #set_classes, #set_data, #set_feature_type, #set_features, #set_opt

Methods included from ReplaceMissingValues

#replace_by_fixed_value!, #replace_by_knn_value!, #replace_by_mean_value!, #replace_by_median_value!, #replace_by_most_seen_value!

Methods included from FileIO

#data_from_csv, #data_from_libsvm, #data_from_random, #data_from_url, #data_from_weka, #data_to_csv, #data_to_libsvm, #data_to_weka

Constructor Details

This class inherits a constructor from FSelector::BaseDiscrete