root/Fit/FcnAdapter.h

0001 // @(#)root/mathcore:$Id$
0002 // Author: L. Moneta    10/2005
0003
0004 /**********************************************************************
0005  *                                                                    *
0006  * Copyright (c) 2005 ROOT Foundation,  CERN/PH-SFT                   *
0007  *                                                                    *
0008  **********************************************************************/
0009
0010 #ifndef ROOT_Fit_FcnAdapter_H_
0011 #define ROOT_Fit_FcnAdapter_H_
0012
0013 #include "Math/IFunction.h"
0014
0015
0016 //___________________________________________________________
0017 //
0018 // Adapt the interface used in TMinuit (and the TVirtualFitter) for
0019 // passing the objective function in a IFunction  interface
0020 // (ROOT::Math::IMultiGenFunction)
0021 //
0022
0023 namespace ROOT {
0024
0025    namespace Fit {
0026
0027 class FcnAdapter : public ROOT::Math::IMultiGenFunction {
0028
0029 public:
0030
0031    FcnAdapter(void (*fcn)(int&, double*, double&, double*, int ), int dim = 0) :
0032       fDim(dim),
0033       fFCN(fcn)
0034    {}
0035
0036    ~FcnAdapter() override {}
0037
0038     unsigned int NDim() const override { return fDim; }
0039
0040    ROOT::Math::IMultiGenFunction * Clone() const override {
0041       return new FcnAdapter(fFCN,fDim);
0042    }
0043
0044    void SetDimension(int dim) { fDim = dim; }
0045
0046 private:
0047
0048    double DoEval(const double * x) const override {
0049       double fval = 0;
0050       int dim = fDim;
0051       // call with flag 4
0052       fFCN(dim, nullptr, fval, const_cast<double *>(x), 4);
0053       return fval;
0054    }
0055
0056 private:
0057
0058    unsigned int fDim;
0059    void (*fFCN)(int&, double*, double&, double*, int);
0060
0061 };
0062
0063    } // end namespace Fit
0064
0065 } // end namespace ROOT
0066
0067 #endif //ROOT_Fit_FcnAdapter