// @(#)root/minuit2:$Id: NegativeG2LineSearch.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                *
 *                                                                    *
 **********************************************************************/

#ifndef ROOT_Minuit2_NegativeG2LineSearch
#define ROOT_Minuit2_NegativeG2LineSearch

namespace ROOT {

   namespace Minuit2 {


class MnFcn;
class MinimumState;
class GradientCalculator;
class MnMachinePrecision;
class FunctionGradient;

/** In case that one of the components of the second derivative g2 calculated 
    by the numerical Gradient calculator is negative, a 1dim line search in 
    the direction of that component is done in order to find a better position 
    where g2 is again positive. 
 */

class NegativeG2LineSearch {

public:

  NegativeG2LineSearch() {}
  
  ~NegativeG2LineSearch() {}

  MinimumState operator()(const MnFcn&, const MinimumState&, const  GradientCalculator&, const MnMachinePrecision&) const;

  bool HasNegativeG2(const FunctionGradient&, const MnMachinePrecision&) const;

private:

};

  }  // namespace Minuit2

}  // namespace ROOT

#endif  // ROOT_Minuit2_NegativeG2LineSearch
