Class: FSelector::OddsRatio
- Inherits:
-
BaseDiscrete
- Object
- Base
- BaseDiscrete
- FSelector::OddsRatio
- 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
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