TF1Helper.h

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// @(#)root/hist:$Id$
// Author: Lorenzo Moneta 12/06/07
 
/**********************************************************************
 *                                                                    *
 * Copyright (c) 2007  LCG ROOT Math Team, CERN/PH-SFT                *
 *                                                                    *
 *                                                                    *
 **********************************************************************/
 
// helper functions used internally by TF1
 
#ifndef ROOT_TF1Helper
#define ROOT_TF1Helper
 
#include "TF1.h"
 
namespace ROOT {
 
   namespace TF1Helper {
 
      double IntegralError(TF1 * func, int dim, const double * a, const double * b, const double * params, const double * covmat, double eps);
 
  /**
     function class representing the derivative with respect a parameter of a given TF1
  */
      class TGradientParFunction {
 
      public:
 
         TGradientParFunction(int ipar, TF1 * f)  :
            fPar(ipar),
            fFunc(f)
         {}
 
         double operator() (double * x, double *) const
         {
            // evaluate gradient vector of functions at point x
            return fFunc->GradientPar(fPar,x);
         }
 
      private:
 
         unsigned int fPar;
         mutable TF1 * fFunc;
      };
 
 
   } // end namespace TF1Helper
 
} // end namespace TF1
 
#endif