Quad1F.h

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// @(#)root/minuit2:$Id: Quad1F.h 20880 2007-11-19 11:23:41Z rdm $
// Authors: M. Winkler, F. James, L. Moneta, A. Zsenei   2003-2005  

/**********************************************************************
 *                                                                    *
 * Copyright (c) 2005 LCG ROOT Math team,  CERN/PH-SFT                *
 *                                                                    *
 **********************************************************************/

#include "Minuit2/FCNGradientBase.h"

namespace ROOT {

   namespace Minuit2 {


class Quad1F : public FCNGradientBase {

public:

  Quad1F() : fErrorDef(1.) {}

  ~Quad1F() {}

  double operator()(const std::vector<double>& par) const {

    double x = par[0];

    return ( x*x );
  }
  
  std::vector<double> Gradient(const std::vector<double>& par) const {
    
    double x = par[0];
    
    return ( std::vector<double>(1, 2.*x) );  
  }

  void SetErrorDef(double up) {fErrorDef = up;}

  double Up() const {return fErrorDef;}

  const FCNBase* Base() const {return this;}

private:
  double fErrorDef;
};


  }  // namespace Minuit2

}  // namespace ROOT

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