CrossEntropy.h

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// @(#)root/tmva $Id$       
// Author: Andreas Hoecker, Joerg Stelzer, Helge Voss, Kai Voss 
 
/**********************************************************************************
 * Project: TMVA - a Root-integrated toolkit for multivariate data analysis       *
 * Package: TMVA                                                                  *
 * Class  : CrossEntropy                                                          *
 *                                             *
 *                                                                                *
 * Description: Implementation of the CrossEntropy as separation criterion        *
 *                                                                                *
 * Authors (alphabetical):                                                        *
 *      Andreas Hoecker <Andreas.Hocker@cern.ch> - CERN, Switzerland              *
 *      Helge Voss      <Helge.Voss@cern.ch>     - MPI-K Heidelberg, Germany      *
 *      Kai Voss        <Kai.Voss@cern.ch>       - U. of Victoria, Canada         *
 *                                                                                *
 * Copyright (c) 2005:                                                            *
 *      CERN, Switzerland                                                         * 
 *      U. of Victoria, Canada                                                    * 
 *      Heidelberg U., Germany                                                    * 
 *                                                                                *
 * Redistribution and use in source and binary forms, with or without             *
 * modification, are permitted according to the terms listed in LICENSE           *
 * (see tmva/doc/LICENSE)                                          *
 **********************************************************************************/
 
#ifndef ROOT_TMVA_CrossEntropy
#define ROOT_TMVA_CrossEntropy
 
//////////////////////////////////////////////////////////////////////////
//                                                                      //
// CrossEntropy                                                         //
//                                                                      //
// Implementation of the CrossEntropy as separation criterion           //
//  -p log (p) - (1-p)log(1-p);     p=purity = s/(s+b)                  // 
//                                                                      //
//////////////////////////////////////////////////////////////////////////
 
#include "TMVA/SeparationBase.h"
 
namespace TMVA {
 
   class CrossEntropy : public SeparationBase {
 
   public:
    
      // default constructor
   CrossEntropy(): SeparationBase()  { fName = "CE"; }
 
      // copy constructor
   CrossEntropy( const CrossEntropy& g): SeparationBase(g) {}
 
      // destructor
      virtual ~CrossEntropy(){}
 
      // return the separation Index  -p log (p) - (1-p)log(1-p);     p=purity = s/(s+b) 
      virtual Double_t GetSeparationIndex( const Double_t s, const Double_t b );
    
   protected:
    
      ClassDef(CrossEntropy,0); // Implementation of the CrossEntropy as separation criterion
   };
 
} // namespace TMVA
 
#endif