root/Minuit2/NegativeG2LineSearch.h

0001 // @(#)root/minuit2:$Id$
0002 // Authors: M. Winkler, F. James, L. Moneta, A. Zsenei   2003-2005
0003
0004 /**********************************************************************
0005  *                                                                    *
0006  * Copyright (c) 2005 LCG ROOT Math team,  CERN/PH-SFT                *
0007  *                                                                    *
0008  **********************************************************************/
0009
0010 #ifndef ROOT_Minuit2_NegativeG2LineSearch
0011 #define ROOT_Minuit2_NegativeG2LineSearch
0012
0013 namespace ROOT {
0014
0015 namespace Minuit2 {
0016
0017 class MnFcn;
0018 class MinimumState;
0019 class GradientCalculator;
0020 class MnMachinePrecision;
0021 class FunctionGradient;
0022
0023 /** In case that one of the components of the second derivative g2 calculated
0024     by the numerical Gradient calculator is negative, a 1dim line search in
0025     the direction of that component is done in order to find a better position
0026     where g2 is again positive.
0027  */
0028
0029 class NegativeG2LineSearch {
0030 public:
0031    MinimumState
0032    operator()(const MnFcn &, const MinimumState &, const GradientCalculator &, const MnMachinePrecision &) const;
0033
0034    bool HasNegativeG2(const FunctionGradient &, const MnMachinePrecision &) const;
0035 };
0036
0037 } // namespace Minuit2
0038
0039 } // namespace ROOT
0040
0041 #endif // ROOT_Minuit2_NegativeG2LineSearch