GSLFunctionWrapper.h

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// @(#)root/mathmore:$Id$
// Authors: L. Moneta, A. Zsenei   08/2005
 
 /**********************************************************************
  *                                                                    *
  * Copyright (c) 2004 ROOT Foundation,  CERN/PH-SFT                   *
  *                                                                    *
  * This library is free software; you can redistribute it and/or      *
  * modify it under the terms of the GNU General Public License        *
  * as published by the Free Software Foundation; either version 2     *
  * of the License, or (at your option) any later version.             *
  *                                                                    *
  * This library is distributed in the hope that it will be useful,    *
  * but WITHOUT ANY WARRANTY; without even the implied warranty of     *
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU   *
  * General Public License for more details.                           *
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  * You should have received a copy of the GNU General Public License  *
  * along with this library (see file COPYING); if not, write          *
  * to the Free Software Foundation, Inc., 59 Temple Place, Suite      *
  * 330, Boston, MA 02111-1307 USA, or contact the author.             *
  *                                                                    *
  **********************************************************************/
 
// Header file for class GSLFunctionWrapper
//
// Created by: moneta  at Sat Nov 13 14:54:41 2004
//
// Last update: Sat Nov 13 14:54:41 2004
//
#ifndef ROOT_Math_GSLFunctionWrapper
#define ROOT_Math_GSLFunctionWrapper
 
#include "gsl/gsl_math.h"
 
#include "Math/GSLFunctionAdapter.h"
 
#include <cassert>
 
namespace ROOT {
namespace Math {
 
 
 
typedef double ( * GSLFuncPointer ) ( double, void *);
typedef void ( * GSLFdfPointer ) ( double, void *, double *, double *);
 
 
/**
   Wrapper class to the gsl_function C structure.
   This class to fill the GSL C structure  gsl_function with
   the C++ function objcet.
   Use the class ROOT::Math::GSLFunctionAdapter to adapt the
   C++ function object to the right signature (function pointer type)
   requested by GSL
*/
class GSLFunctionWrapper {
 
public:
 
   GSLFunctionWrapper()
   {
      fFunc.function = nullptr;
      fFunc.params = nullptr;
   }
 
   /// set in the GSL C struct the pointer to the function evaluation
   void SetFuncPointer( GSLFuncPointer f) { fFunc.function = f; }
 
   /// set in the GSL C struct the extra-object pointer
   void SetParams ( void * p) { fFunc.params = p; }
 
   /// fill the GSL C struct from a generic C++ callable object
   /// implementing operator()
   template<class FuncType>
   void SetFunction(const FuncType &f) {
      const void * p = &f;
      assert (p != nullptr);
      SetFuncPointer(&GSLFunctionAdapter<FuncType >::F);
      SetParams(const_cast<void *>(p));
   }
 
   gsl_function * GetFunc() { return &fFunc; }
 
   GSLFuncPointer FunctionPtr() { return fFunc.function; }
 
   // evaluate the function
   double operator() (double x) {  return GSL_FN_EVAL(&fFunc, x); }
 
   /// check if function is valid (has been set)
   bool IsValid() {
      return (fFunc.function != nullptr) ? true : false;
   }
 
private:
   gsl_function fFunc;
 
 
};
 
 
   /**
     class to wrap a gsl_function_fdf (with derivatives)
   */
  class GSLFunctionDerivWrapper {
 
  public:
 
     GSLFunctionDerivWrapper()
     {
        fFunc.f = nullptr;
        fFunc.df = nullptr;
        fFunc.fdf = nullptr;
        fFunc.params = nullptr;
     }
 
 
    void SetFuncPointer( GSLFuncPointer f) { fFunc.f = f; }
    void SetDerivPointer( GSLFuncPointer f) { fFunc.df = f; }
    void SetFdfPointer( GSLFdfPointer f) { fFunc.fdf = f; }
    void SetParams ( void * p) { fFunc.params = p; }
 
 
    gsl_function_fdf * GetFunc() { return &fFunc; }
 
    // evaluate the function and derivatives
    double operator() (double x) {  return GSL_FN_FDF_EVAL_F(&fFunc, x); }
 
    double Derivative (double x) { return GSL_FN_FDF_EVAL_DF(&fFunc, x); }
 
    void Fdf(double x, double & f, double & df) {
      return GSL_FN_FDF_EVAL_F_DF(&fFunc, x, &f, &df);
    }
 
   /// check if function is valid (has been set)
   bool IsValid() {
      return (fFunc.f != nullptr ) ? true : false;
   }
 
  private:
    gsl_function_fdf fFunc;
 
  };
 
 
 
} // namespace Math
} // namespace ROOT
 
#endif /* ROOT_Math_GSLFunctionWrapper */