Class: Newral::ProbabilitySet

Inherits:
Object
  • Object
show all
Defined in:
lib/newral/probability_set.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ProbabilitySet

Returns a new instance of ProbabilitySet.



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# File 'lib/newral/probability_set.rb', line 5

def initialize(  )
  @probabilities={}
  @history = []
end

Instance Attribute Details

#history ⇒ Object (readonly)

Returns the value of attribute history.



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# File 'lib/newral/probability_set.rb', line 4

def history
  @history
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/newral/probability_set.rb', line 10

def []( key )
  @probabilities[ key ] || ( @probabilities[key] = compute(key))
end

#add(key, other_key, set_value: nil) ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object

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



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# 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) ⇒ Object

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®/P(H) = 0.9*0.01/ =0.097*0.01 P(H) = P 0.5244999999999999



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# 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) ⇒ Object 



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# File 'lib/newral/probability_set.rb', line 14

def set( key, set_value )
  @probabilities[ key ] = set_value
end

#total(key, apriori: nil) ⇒ Object 



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# 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