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Source Code for Module fuzzy.defuzzify.COG

 1  # -*- coding: utf-8 -*- 
 2  # 
 3  # Copyright (C) 2009  Rene Liebscher 
 4  # 
 5  # This program is free software; you can redistribute it and/or modify it under 
 6  # the terms of the GNU Lesser General Public License as published by the Free  
 7  # Software Foundation; either version 3 of the License, or (at your option) any 
 8  # later version. 
 9  # 
10  # This program is distributed in the hope that it will be useful, but WITHOUT  
11  # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 
12  # FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more 
13  # details. 
14  #  
15  # You should have received a copy of the GNU Lesser General Public License 
16  # along with this program; if not, see <http://www.gnu.org/licenses/>.  
17  # 
18   
19  """Defuzzification which uses the center of gravity method.""" 
20   
21  __revision__ = "$Id: COG.py,v 1.9 2010-03-28 18:40:33 rliebscher Exp $" 
22   
23  from fuzzy.defuzzify.Base import Base 
24   
25 -class COG(Base): 
26      """Defuzzification which uses 
27         the center of gravity method.""" 
28   
29 -    def __init__(self, INF=None, ACC=None, failsafe=None, segment_size=None, *args, **keywords): 
30          """ 
31              @param failsafe: if is not possible to calculate a center of gravity, 
32                               return this value if not None or forward the exception 
33              @param segment_size: maximum length of segment in polygon of accumulated result set 
34          """  
35          super(COG, self).__init__(INF, ACC, *args, **keywords) 
36          self.failsafe = failsafe # which value if COG not calculable 
37          self.segment_size = segment_size # maximum length of segment in polygon of accumulated result set 
38   
39 -    def getValue(self, variable): 
40          """Defuzzification using center of gravity method.""" 
41          temp = self.accumulate(variable, self.segment_size) 
42          try: 
43              return temp.getCOG() 
44          except: 
45              # was not to calculate 
46              if self.failsafe is not None: 
47                  # user gave us a value to return 
48                  return self.failsafe 
49              else: 
50                  # forward exception 
51                  raise 
52   
53 -    def _repr_params(self, params): 
54          """Helper for representation of instance. 
55           
56          Add all own params to given list in params.     
57          """ 
58          super(COG, self)._repr_params(params) 
59          if self.failsafe: params.append("failsafe=%s" % self.failsafe)  
60          if self.segment_size: params.append("segment_size=%s" % self.segment_size) 
61   

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