FCNGradAdapter.h

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// @(#)root/minuit2:$Id$
// Author: L. Moneta    10/2006
 
/**********************************************************************
 *                                                                    *
 * Copyright (c) 2006 ROOT Foundation,  CERN/PH-SFT                   *
 *                                                                    *
 **********************************************************************/
 
#ifndef ROOT_Minuit2_FCNGradAdapter
#define ROOT_Minuit2_FCNGradAdapter
 
#include "Minuit2/FCNGradientBase.h"
 
//#define DEBUG
#ifdef DEBUG
#include <iostream>
#endif
 
namespace ROOT {
 
   namespace Minuit2 {
 
/**
 
 
template wrapped class for adapting to FCNBase signature a IGradFunction
 
@author Lorenzo Moneta
 
@ingroup Minuit
 
*/
 
template< class Function>
class FCNGradAdapter : public FCNGradientBase {
 
public:
 
   FCNGradAdapter(const Function & f, double up = 1.) :
      fFunc(f) ,
      fUp (up) ,
      fGrad(std::vector<double>(fFunc.NDim() ) )
 
   {}
 
   ~FCNGradAdapter() {}
 
 
   double operator()(const std::vector<double>& v) const {
      return fFunc.operator()(&v[0]);
   }
   double operator()(const double *  v) const {
      return fFunc.operator()(v);
   }
 
   double Up() const {return fUp;}
 
   std::vector<double> Gradient(const std::vector<double>& v) const {
      fFunc.Gradient(&v[0], &fGrad[0]);
 
#ifdef DEBUG
      std::cout << " gradient in FCNAdapter = { " ;
      for (unsigned int i = 0; i < fGrad.size(); ++i)
         std::cout << fGrad[i] << "\t";
      std::cout << "}" << std::endl;
#endif
      return fGrad;
   }
   // forward interface
   //virtual double operator()(int npar, double* params,int iflag = 4) const;
   bool CheckGradient() const { return false; }
 
private:
   const Function & fFunc;
   double fUp;
   mutable std::vector<double> fGrad;
};
 
   } // end namespace Minuit2
 
} // end namespace ROOT
 
 
 
#endif //ROOT_Minuit2_FCNGradAdapter