GSLMultiMinFunctionWrapper.h

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// @(#)root/mathmore:$Id$
// Authors: L. Moneta, 12/2006

 /**********************************************************************
  *                                                                    *
  * 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        *
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  * 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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// Header file for class GSLMultiMinFunctionWrapper
//
// Created by: moneta  at Sat Nov 13 14:54:41 2004
//
// Last update: Sat Nov 13 14:54:41 2004
//
#ifndef ROOT_Math_GSLMultiMinFunctionWrapper
#define ROOT_Math_GSLMultiMinFunctionWrapper

#include "gsl/gsl_multimin.h"

#include "GSLMultiMinFunctionAdapter.h"


#include <cassert>

namespace ROOT {
namespace Math {



   typedef double ( * GSLMultiMinFuncPointer ) ( const gsl_vector *, void *);
   typedef void   ( * GSLMultiMinDfPointer )   ( const gsl_vector *, void *, gsl_vector *);
   typedef void   ( * GSLMultiMinFdfPointer ) ( const gsl_vector *, void *, double *, gsl_vector *);


/**
   wrapper to a multi-dim function withtout  derivatives for multi-dimensional
   minimization algorithm

   @ingroup MultiMin
*/

class GSLMultiMinFunctionWrapper {

public:

   GSLMultiMinFunctionWrapper()
   {
      fFunc.f = 0;
      fFunc.n = 0;
      fFunc.params = 0;
   }

   void SetFuncPointer( GSLMultiMinFuncPointer f) { fFunc.f = f; }
   void SetDim  ( unsigned int n ) { fFunc.n = n; }
   void SetParams ( void * p) { fFunc.params = p; }

   /// Fill gsl function structure from a C++ Function class
   template<class FuncType>
   void SetFunction(const FuncType &f) {
      const void * p = &f;
      assert (p != 0);
      SetFuncPointer(&GSLMultiMinFunctionAdapter<FuncType >::F);
      SetDim( f.NDim() );
      SetParams(const_cast<void *>(p));
   }

   gsl_multimin_function * GetFunc() { return &fFunc; }

    bool IsValid() {
       return (fFunc.f != 0) ? true : false;
    }


  private:

    gsl_multimin_function fFunc;

  };


/**
   Wrapper for a multi-dimensional function with derivatives used in GSL multidim
   minimization algorithm

   @ingroup MultiMin

 */
 class GSLMultiMinDerivFunctionWrapper {

 public:

    GSLMultiMinDerivFunctionWrapper()
    {
       fFunc.f = 0;
       fFunc.df = 0;
       fFunc.fdf = 0;
       fFunc.n = 0;
       fFunc.params = 0;
    }


    void SetFuncPointer( GSLMultiMinFuncPointer f) { fFunc.f = f; }
    void SetDerivPointer( GSLMultiMinDfPointer f) { fFunc.df = f; }
    void SetFdfPointer( GSLMultiMinFdfPointer f) { fFunc.fdf = f; }
    void SetDim  ( unsigned int n ) { fFunc.n = n; }
    void SetParams ( void * p) { fFunc.params = p; }

    /// Fill gsl function structure from a C++ Function class
    template<class FuncType>
    void SetFunction(const FuncType &f) {
       const void * p = &f;
       assert (p != 0);
       SetFuncPointer(&GSLMultiMinFunctionAdapter<FuncType >::F);
       SetDerivPointer(&GSLMultiMinFunctionAdapter<FuncType >::Df);
       SetFdfPointer(&GSLMultiMinFunctionAdapter<FuncType >::Fdf);
       SetDim( f.NDim() );
       SetParams(const_cast<void *>(p));
     }

    gsl_multimin_function_fdf * GetFunc() { return &fFunc; }

#ifdef NEEDED_LATER
    // evaluate the function
    double operator() (const double * x) {
       // vx must be a gsl_vector
       return GSL_MULTIMIN_FN_EVAL(&fFunc, vx);
    }
#endif

   /// check if function is valid (has been set)
    bool IsValid() {
       return (fFunc.f != 0) ? true : false;
    }

 private:

    gsl_multimin_function_fdf fFunc;

  };




} // namespace Math
} // namespace ROOT

#endif /* ROOT_Math_GSLMultiMinFunctionWrapper */