lib/ankusa/naive_bayes.rb in ankusa-0.0.13 vs lib/ankusa/naive_bayes.rb in ankusa-0.0.14

@@ -11,11 +11,11 @@
     
     # Classes is an array of classes to look at
     def classifications(text, classnames=nil)
       result = log_likelihoods text, classnames
       result.keys.each { |k|
-        result[k] = (result[k] == INFTY) ? 0 : Math.exp(result[k])
+        result[k] = (result[k] == -INFTY) ? 0 : Math.exp(result[k])
       }
 
       # normalize to get probs
       sum = result.values.inject { |x,y| x+y }
       result.keys.each { |k| result[k] = result[k] / sum }
@@ -28,11 +28,11 @@
       result = Hash.new 0
 
       TextHash.new(text).each { |word, count|
         probs = get_word_probs(word, classnames)
         classnames.each { |k| 
-          # log likelihood should be infinity if we've never seen the klass
-          result[k] += probs[k] > 0 ? (Math.log(probs[k]) * count) : INFTY
+          # log likelihood should be negative infinity if we've never seen the klass
+          result[k] += probs[k] > 0 ? (Math.log(probs[k]) * count) : -INFTY
         }
       }
 
       # add the prior
       doc_counts = doc_count_totals.select { |k,v| classnames.include? k }.map { |k,v| v }