www.pudn.com > firev0.01.rar > chisquaredistance.hpp

/*
This file is part of the FIRE -- Flexible Image Retrieval System

FIRE is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

FIRE is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with FIRE; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#ifndef __chisquaredistance_hpp
#define __chisquaredistance_hpp

#include 
#include "basedist.hpp"
/** 
 * This class implements the Chi-square distance as subclass of
 * BaseDist. The functions itself are not documented. @see BaseDist
 * for further information.
 */
class ChiSquareDistance : public BaseDist {

public:
  ChiSquareDistance() {};

  virtual double dist(const BaseFeature *a, const BaseFeature *b) const {
    double result=.0;
    double tmp;
    unsigned int nOfBins=a->size();
    double n1, n2;
    for(unsigned int i=0;ioperator[](i);
      n2=b->operator[](i);
      
      if(n1+n2!=0) {
        tmp=n1-n2;
        tmp*=tmp;
        tmp/=(n1+n2);
        
        result+=tmp;
      }
    }
    return result;
  }

  virtual double dist(const BaseFeature *a, const vector &b) const {
    double result=.0;
    double tmp;
    unsigned int nOfBins=a->size();
    double n1, n2;
    for(unsigned int i=0;ioperator[](i);
      n2=b[i];
      
      if(n1+n2!=0) {
        tmp=n1-n2;
        tmp*=tmp;
        tmp/=(n1+n2);
        
        result+=tmp;
      } 
    }
    

    return result;
  }
  virtual std::string name() {
    return "chisquare";
  }


};


#endif