class Newral::ProbabilitySet

Attributes

history[R]

Public Class Methods

new( ) click to toggle source
# File lib/newral/probability_set.rb, line 5
def initialize(  )
  @probabilities={}
  @history = []
end

Public Instance Methods

[]( key ) click to toggle source
# File lib/newral/probability_set.rb, line 10
def []( key )
  @probabilities[ key ] || ( @probabilities[key] = compute(key))
end
add( key,other_key, set_value: nil ) click to toggle source
# File lib/newral/probability_set.rb, line 39
def add( key,other_key, set_value: nil )
  computed_key_name = "#{key}+#{other_key}"
  return @probabilities[ computed_key_name] if @probabilities[ computed_key_name ] && set_value.nil?
  set_value ||= compute( key )+compute( other_key )
  set( computed_key_name, set_value )
end
and( key,other_key, set_value: nil ) click to toggle source
# File lib/newral/probability_set.rb, line 60
def and( key,other_key, set_value: nil )
  computed_key_name = "#{key}^#{other_key}"
  return @probabilities[computed_key_name ] if @probabilities[ computed_key_name ] &&set_value.nil?
  set_value ||= compute("#{key}|#{other_key}")*compute(other_key)
  set( computed_key_name, set_value )
end
aposteriori( key,apriori:nil, set_value: nil ) click to toggle source

aposteriori =( Likelihood * Prior )/ marginal likelihood P(A|B) = P(B|A)*P(A)/P(B)

# File lib/newral/probability_set.rb, line 47
def aposteriori( key,apriori:nil, set_value: nil )
  computed_key_name = "#{key}|#{apriori}"
  return @probabilities[ computed_key_name ] if @probabilities[ computed_key_name ] &&set_value.nil?
  set_value ||= compute("#{apriori}|#{key}")*compute(key)/compute(apriori)
 set( computed_key_name, set_value )
end
compute( key ) click to toggle source

P(R|H,S) = P(H|R,S)*P(R|S)/P(H|S) P(R|H,!S) = P(H|R,!S)*P(R|!S)/P(H|!S) 0.9*0.01/(0.9*0.01+0.1*0.99) P(R|H) = P(H|R)*P(R)/P(H) = 0.9*0.01/ =0.097*0.01 P(H) = P 0.5244999999999999

# File lib/newral/probability_set.rb, line 80
def compute( key )
  probability = if @probabilities[key]
    @probabilities[key]
  elsif key.start_with?("!") && @probabilities[key.sub("!","")]
    self.not(key.sub("!",''))
  elsif key.match('\|')
    @history << key unless @history.member?( key )
    key,apriori=key.split("|")
    self.aposteriori( key, apriori: apriori)
  elsif key.match('\^')
    @history << key unless @history.member?( key )
    key,other_key=key.split("^")
    self.and(key,other_key)
  else
    apriori_key = @probabilities.keys.find{|p| p.split("|")[0]==key && !p.split("|")[1].match('!') }
    if apriori_key
      @history << key unless @history.member?( key )
      apriori_key = apriori_key.split("|")[1]
      value = self.total(key,apriori: apriori_key)
      self.set( key, value)
    else 
      raise "not found #{key}"
    end
  end
  probability
end
divide( key,other_key, set_value: nil ) click to toggle source
# File lib/newral/probability_set.rb, line 25
def divide( key,other_key, set_value: nil )
  computed_key_name = "#{key}/#{other_key}"
  return @probabilities[ computed_key_name ] if @probabilities[ computed_key_name] &&set_value.nil?
  set_value ||= compute( key )*compute( other_key )
  set( computed_key_name, set_value )
end
multiply( key,other_key, set_value: nil ) click to toggle source
# File lib/newral/probability_set.rb, line 18
def multiply( key,other_key, set_value: nil )
  computed_key_name = "#{key}*#{other_key}"
  return @probabilities[computed_key_name] if @probabilities[ computed_key_name ] &&set_value.nil?
  set_value ||= compute( key )*compute( other_key )
  set( computed_key_name, set_value )
end
not( key, set_value: nil ) click to toggle source
# File lib/newral/probability_set.rb, line 32
def not( key, set_value: nil )
  computed_key_name = "!#{key}"
  return @probabilities[ computed_key_name ] if @probabilities[computed_key_name ] &&set_value.nil?
  set_value ||= 1-compute( key )
  set( computed_key_name, set_value )
end
or( key,other_key, set_value: nil ) click to toggle source
# File lib/newral/probability_set.rb, line 67
def or(  key,other_key, set_value: nil )
  computed_key_name = "#{key}.#{other_key}"
  return @probabilities[ computed_key_name ] if @probabilities[computed_key_name] &&set_value.nil?
  set_value ||= compute(key)+compute(other_key)-compute("#{key}^#{other_key}")
  set( computed_key_name, set_value )
end
set( key, set_value ) click to toggle source
# File lib/newral/probability_set.rb, line 14
def set( key, set_value )
  @probabilities[ key ] = set_value
end
total( key, apriori: nil ) click to toggle source
# File lib/newral/probability_set.rb, line 55
def total( key, apriori: nil )
  aposteriori(key,apriori: apriori)*compute(apriori)+self.aposteriori(key,apriori: "!#{apriori}")*self.not(apriori)
end