AnalyticalGradientCalculator.cxx

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// @(#)root/minuit2:$Id$
// Authors: M. Winkler, F. James, L. Moneta, A. Zsenei   2003-2005
 
/**********************************************************************
 *                                                                    *
 * Copyright (c) 2005 LCG ROOT Math team,  CERN/PH-SFT                *
 *                                                                    *
 **********************************************************************/
 
#include "Minuit2/AnalyticalGradientCalculator.h"
#include "Minuit2/FCNGradientBase.h"
#include "Minuit2/MnUserTransformation.h"
#include "Minuit2/FunctionGradient.h"
#include "Minuit2/MinimumParameters.h"
#include "Minuit2/MnMatrix.h"
#include "Minuit2/MnPrint.h"
 
namespace ROOT {
namespace Minuit2 {
 
FunctionGradient AnalyticalGradientCalculator::operator()(const MinimumParameters &par) const
{
   // evaluate analytical gradient. take care of parameter transformations
 
   std::vector<double> grad = fGradCalc.Gradient(fTransformation(par.Vec()));
   assert(grad.size() == fTransformation.Parameters().size());
 
   MnAlgebraicVector v(par.Vec().size());
   for (unsigned int i = 0; i < par.Vec().size(); i++) {
      unsigned int ext = fTransformation.ExtOfInt(i);
      if (fTransformation.Parameter(ext).HasLimits()) {
         // double dd = (fTransformation.Parameter(ext).Upper() -
         // fTransformation.Parameter(ext).Lower())*0.5*cos(par.Vec()(i));
         //       const ParameterTransformation * pt = fTransformation.transformation(ext);
         //       double dd = pt->dInt2ext(par.Vec()(i), fTransformation.Parameter(ext).Lower(),
         //       fTransformation.Parameter(ext).Upper() );
         double dd = fTransformation.DInt2Ext(i, par.Vec()(i));
         v(i) = dd * grad[ext];
      } else {
         v(i) = grad[ext];
      }
   }
 
   MnPrint print("AnalyticalGradientCalculator");
   print.Debug("User given gradient in Minuit2", v);
 
   return FunctionGradient(v);
}
 
FunctionGradient AnalyticalGradientCalculator::operator()(const MinimumParameters &par, const FunctionGradient &) const
{
   // needed from base class
   return (*this)(par);
}
 
bool AnalyticalGradientCalculator::CheckGradient() const
{
   // check to be sure FCN implements analytical gradient
   return fGradCalc.CheckGradient();
}
 
} // namespace Minuit2
 
} // namespace ROOT