Source Code for Module tipy.mrgr

 1  #!/usr/bin/env python3 
 2  # -*- coding: utf-8 -*- 
 3   
 4  """Merger classes to merge results from several predictors.""" 
 5   
 6  import tipy.prdct 
 7  from abc import ABCMeta, abstractmethod 
 8   
 9   
10 -class Merger(object): 
11      """Base class for all Mergers. 
12   
13      G{classtree Merger} 
14      """ 
15   
16      __metaclass__ = ABCMeta 
17      MIN_PROBABILITY = 0.0 
18      MAX_PROBABILITY = 1.0 
19   
20 -    def __init__(self): 
21          """Merger creator.""" 
22          self.name = "Merger 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      @abstractmethod 
55 -    def merge(self, predictionList): 
56          """Method for merging predictors's prediction list. 
57   
58          The merge() method is the main method of the Merger. It must be 
59          implemented by every Mergers. 
60          """ 
61          raise NotImplementedError("Method must be implemented") 
62   
63   
64 -class ProbabilisticMerger(Merger): 
65      """Simple Merger which merge suggestions based on their probabilities. 
66   
67      This Merger does not modify the suggestions probabilities. Thus, they are 
68      sorted in descending order according to their probabilities. 
69   
70      G{classtree ProbabilisticMerger} 
71      """ 
72 -    def __init__(self): 
73          """ProbabilisticMerger creator.""" 
74          super(self.__class__, self).__init__() 
75          self.name = 'ProbabilisticMerger' 
76   
77 -    def merge(self, predictionList): 
78          """merge 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 merged 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