// @(#)root/minuit2:$Id$
// Authors: M. Winkler, F. James, L. Moneta, A. Zsenei   2003-2005  

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

#ifndef ROOT_Minuit2_BasicFunctionGradient
#define ROOT_Minuit2_BasicFunctionGradient

#include "Minuit2/MnMatrix.h"

#include "Minuit2/StackAllocator.h"

namespace ROOT {

   namespace Minuit2 {


//extern StackAllocator gStackAllocator;

class BasicFunctionGradient {

private:

public:
  
  explicit BasicFunctionGradient(unsigned int n) :
    fGradient(MnAlgebraicVector(n)), fG2ndDerivative(MnAlgebraicVector(n)),
    fGStepSize(MnAlgebraicVector(n)), fValid(false), 
    fAnalytical(false) {}
  
  explicit BasicFunctionGradient(const MnAlgebraicVector& grd) : 
    fGradient(grd), fG2ndDerivative(MnAlgebraicVector(grd.size())),
    fGStepSize(MnAlgebraicVector(grd.size())), fValid(true), 
    fAnalytical(true) {}

  BasicFunctionGradient(const MnAlgebraicVector& grd, const MnAlgebraicVector& g2, const MnAlgebraicVector& gstep) : 
    fGradient(grd), fG2ndDerivative(g2),
    fGStepSize(gstep), fValid(true), fAnalytical(false) {}
  
  ~BasicFunctionGradient() {}
  
  BasicFunctionGradient(const BasicFunctionGradient& grad) : fGradient(grad.fGradient), fG2ndDerivative(grad.fG2ndDerivative), fGStepSize(grad.fGStepSize), fValid(grad.fValid) {}

  BasicFunctionGradient& operator=(const BasicFunctionGradient& grad) {
    fGradient = grad.fGradient;
    fG2ndDerivative = grad.fG2ndDerivative;
    fGStepSize = grad.fGStepSize;
    fValid = grad.fValid;
    return *this;
  }

  void* operator new(size_t nbytes) {
    return StackAllocatorHolder::Get().Allocate(nbytes);
  }
  
  void operator delete(void* p, size_t /*nbytes */) {
    StackAllocatorHolder::Get().Deallocate(p);
  }

  const MnAlgebraicVector& Grad() const {return fGradient;}
  const MnAlgebraicVector& Vec() const {return fGradient;}
  bool IsValid() const {return fValid;}

  bool IsAnalytical() const {return fAnalytical;}
  const MnAlgebraicVector& G2() const {return fG2ndDerivative;}
  const MnAlgebraicVector& Gstep() const {return fGStepSize;}

private:

  MnAlgebraicVector fGradient;
  MnAlgebraicVector fG2ndDerivative;
  MnAlgebraicVector fGStepSize;
  bool fValid;
  bool fAnalytical;
};

  }  // namespace Minuit2

}  // namespace ROOT

#endif  // ROOT_Minuit2_BasicFunctionGradient