Source Code for Module tipy.cmbn

 1  #!/usr/bin/env python3 
 2  # -*- coding: utf-8 -*- 
 3   
 4  """Combiner classes to merge results from several predictors.""" 
 5   
 6  import tipy.prdct 
 7  import abc 
 8   
 9   
10 -class Combiner(object): 
11      """Base class for all combiners. 
12   
13      G{classtree Combiner} 
14      """ 
15   
16      __metaclass__ = abc.ABCMeta 
17      MIN_PROBABILITY = 0.0 
18      MAX_PROBABILITY = 1.0 
19   
20 -    def __init__(self): 
21          """Combiner creator.""" 
22          self.name = "Combiner dosen't set any name" 
23   
24 -    def filter(self, prediction): 
25          """Sort the tokens according to their probabilities. 
26   
27          The duplicate tokens are merged to a single token (their probabilities 
28          are summed). 
29   
30          @param prediction: 
31              It is a list of Suggestion instances. 
32          @type prediction: L{prdct.Prediction} 
33   
34          @return: 
35              The sorted Prediction instance. 
36          @rtype: Prediction 
37          """ 
38          seen_tokens = set() 
39          result = tipy.prdct.Prediction() 
40          for i, suggestion in enumerate(prediction): 
41              token = suggestion.word 
42              if token not in seen_tokens: 
43                  for j in range(i + 1, len(prediction)): 
44                      if token == prediction[j].word: 
45                          suggestion.probability += prediction[j].probability 
46                          if suggestion.probability > self.MAX_PROBABILITY: 
47                              suggestion.probability = self.MAX_PROBABILITY 
48                          elif suggestion.probability < self.MIN_PROBABILITY: 
49                              suggestion.probability = self.MIN_PROBABILITY 
50                  seen_tokens.add(token) 
51                  result.add_suggestion(suggestion) 
52          return result 
53   
54      @abc.abstractmethod 
55 -    def combine(self, predictionList): 
56          """Method for combining predictors's prediction list. 
57   
58          The combine() method is the main method of the Combiner. It must be 
59          implemented by every combiners. 
60          """ 
61          raise NotImplementedError("Method must be implemented") 
62   
63   
64 -class ProbabilisticCombiner(Combiner): 
65      """Simple combiner which combine suggestions based on their probabilities. 
66   
67      This combiner does not modify the suggestions probabilities. Thus, they are 
68      sorted in descending order according to their probabilities. 
69   
70      G{classtree ProbabilisticCombiner} 
71      """ 
72 -    def __init__(self): 
73          """ProbabilisticCombiner creator.""" 
74          super(self.__class__, self).__init__() 
75          self.name = 'ProbabilisticCombiner' 
76   
77 -    def combine(self, predictionList): 
78          """Combine the suggestions in a single list and sort them. 
79   
80          @param predictionList: 
81              The list of Prediction instances. Each predictors return a 
82              Prediction instance which is added to the list by the 
83              PredictorActivator. 
84          @type predictionList: list 
85   
86          @return: 
87              The combined Prediction instance containing every suggestions of 
88              every Prediction instances sorted in descending order according to 
89              their probabilities. 
90          @rtype: L{prdct.Prediction} 
91          """ 
92          result = tipy.prdct.Prediction() 
93          for prediction in predictionList: 
94              for suggestion in prediction: 
95                  result.add_suggestion(suggestion) 
96          return(self.filter(result)) 
97