Bayes Net Table Probabilities Generator from Positive Negative Relations

Methods
Public Class methods
get_node_probability_from_boolean_combination(boolean_combination, type_of_position_impact)

returns P(node=yes| parents={boolean_combination}) where parents have relations with the node showed in type_of_position_impact type_of_position_impact is a array of boolean values showing the relation ( positive | negative ) beetwen the node and its parents.

[ show source ]

    # File lib/bn4r/bn_table_probabilities.rb, line 56
56:   def self.get_node_probability_from_boolean_combination(boolean_combination, type_of_position_impact)
57:     num_eq = 0.0
58:     boolean_combination.size.times { |i|
59:       num_eq += 1.0 if type_of_position_impact[i] && boolean_combination[i]
60:       num_eq += 1.0 if !type_of_position_impact[i] && !boolean_combination[i]
61:     }
62:     num_eq / boolean_combination.size.to_f
63:   end
Public Instance methods
table_probabilities_for_node(node, type_of_position_impact)

type_of_position_impact is a array of boolean values showing the relation ( positive | negative ) beetwen the node and its parents.

[ show source ]

    # File lib/bn4r/bn_table_probabilities.rb, line 25
25:   def table_probabilities_for_node(node, type_of_position_impact)
26:     raise "Node parents and type_of_position_impact with different size" if node.parents.size != type_of_position_impact.size
27:     boolean_combinations = []
28:     (2**node.parents.size).times { |i|
29:       boolean_combination = Array.new(node.parents.size, false)
30:       actual_value = i
31:       (node.parents.size).times { |j|
32:         boolean_combination[j] = !(actual_value%2 == 0)
33:         actual_value = actual_value / 2
34:       }
35:       boolean_combinations << boolean_combination
36:     }
37:     #p boolean_combinations

38:     table_probabilities = [] # Array.new(2**(node.parents.size+1))

39:     boolean_combinations.each { |boolean_combination|
40:       [true,false].each { |node_value|
41:         prob = BNTPGFromPositiveNegativeRelations.get_node_probability_from_boolean_combination(boolean_combination, type_of_position_impact)
42:         prob = 1 - prob if node_value == false
43:         table_probabilities[node.get_table_index(node_value, boolean_combination)] = prob
44:         #p "pos :" + node.get_table_index(node_value, boolean_combination).to_s

45:         #p "Ok :" + node.get_table_index(node_value, boolean_combination).to_s if node.get_table_index(node_value, boolean_combination) > 2**node.parents.size

46:       }
47:     }
48:    #p table_probabilities

49:    table_probabilities
50:   end