Class: Bayes::PaulGraham

Inherits:
FilterBase show all
Defined in:
lib/bayes.rb

Defined Under Namespace

Classes: Corpus

Instance Attribute Summary

Attributes inherited from FilterBase

#charset, #db_name, #ham, #spam

Instance Method Summary collapse

Methods inherited from FilterBase

#[], #convert, #initialize, #save

Constructor Details

This class inherits a constructor from Bayes::FilterBase

Instance Method Details

#estimate(tokens, take = 15) ⇒ Object 



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# File 'lib/bayes.rb', line 224

def estimate(tokens, take=15)
  s = tokens.uniq.map{|i| score(i)}.compact.sort{|a, b| (0.5-a).abs <=> (0.5-b)}.reverse[0...take]
  return nil if s.empty? || s.include?(1.0) && s.include?(0.0)

  prod = s.inject(1.0){|r, i| r*i}
  return prod/(prod+s.inject(1.0){|r, i| r*(1-i)})
end

#score(token) ⇒ Object 



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# File 'lib/bayes.rb', line 216

def score(token)
  return 0.4 unless @spam.include?(token) or @ham.include?(token)
  g = @ham.count==0 ? 0.0 : [1.0, 2*@ham[token]/@ham.count.to_f].min
  b = @spam.count==0 ? 0.0 : [1.0, @spam[token]/@spam.count.to_f].min
  r = [0.01, [0.99, b/(g+b)].min].max
  r
end