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MisClassificationError.cxx
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1 // @(#)root/tmva $Id$
2 // Author: Andreas Hoecker, Joerg Stelzer, Helge Voss, Kai Voss
3 
4 /**********************************************************************************
5  * Project: TMVA - a Root-integrated toolkit for multivariate data analysis *
6  * Package: TMVA *
7  * Class : MisClassificationError *
8  * Web : http://tmva.sourceforge.net *
9  * *
10  * Description: Implementation of the MisClassificationError as separation *
11  * criterion: 1-max(p, 1-p) as
12  * *
13  * Authors (alphabetical): *
14  * Andreas Hoecker <Andreas.Hocker@cern.ch> - CERN, Switzerland *
15  * Helge Voss <Helge.Voss@cern.ch> - MPI-K Heidelberg, Germany *
16  * Kai Voss <Kai.Voss@cern.ch> - U. of Victoria, Canada *
17  * *
18  * Copyright (c) 2005: *
19  * CERN, Switzerland *
20  * U. of Victoria, Canada *
21  * Heidelberg U., Germany *
22  * *
23  * Redistribution and use in source and binary forms, with or without *
24  * modification, are permitted according to the terms listed in LICENSE *
25  * (http://tmva.sourceforge.net/LICENSE) *
26  **********************************************************************************/
27 
28 /*! \class TMVA::MisClassificationError
29 \ingroup TMVA
30 Implementation of the MisClassificationError as separation criterion
31 */
32 
33 
34 #include "TMVA/MisClassificationError.h"
35 
36 #include "Rtypes.h"
37 
38 ClassImp(TMVA::MisClassificationError);
39 
40 ////////////////////////////////////////////////////////////////////////////////
41 /// Misclassification error criterion: 1-max(p, 1-p) (p: purity= s/(s+b))
42 
43 Double_t TMVA::MisClassificationError::GetSeparationIndex( const Double_t s, const Double_t b )
44 {
45  if ( s+b <= 0) return 0;
46 
47  Double_t p = s/(s+b);
48  if (p >= 1-p) return 1-p;
49  else return p;
50 }
51 
52