GSLMonteFunctionAdapter.h

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// @(#)root/mathmore:$Id: GSLMonteFunctionAdapter.h 21503 2007-12-19 17:34:54Z moneta $
// Authors: L. Moneta, 08/2007 

 /**********************************************************************
  *                                                                    *
  * Copyright (c) 2004 ROOT Foundation,  CERN/PH-SFT                   *
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// Header file for class GSLMultiMinFunctionAdapter
//
// Generic adapter for gsl_multimin_function signature 
// usable for any c++ class which defines operator( ) 
// 
// Created by: Lorenzo Moneta  at Fri Nov 12 16:58:51 2004
// 
// Last update: Fri Nov 12 16:58:51 2004
// 
#ifndef ROOT_Math_GSLMonteFunctionAdapter
#define ROOT_Math_GSLMonteFunctionAdapter


namespace ROOT {
namespace Math {


  /**
     Class for adapting any multi-dimension C++ functor class to C function pointers used by 
     GSL MonteCarlo integration algorithms. 
     The templated C++ function class must implement: 

    <em> double operator( const double *  x)</em>

    This class defines static methods with will be used to fill the 
    \a gsl_monte_function  used by GSL. 
    See for examples the 
    <A HREF="http://www.gnu.org/software/gsl/manual/html_node/Monte-Carlo-Interface.html">GSL online manual</A>

    @ingroup MCIntegration
  */ 
 typedef double ( * GSLMonteFuncPointer ) ( double *, size_t, void *);    

  template<class UserFunc> 
  struct  GSLMonteFunctionAdapter {
    
    static double F( double * x, size_t, void * p) { 
      
      UserFunc * function = reinterpret_cast< UserFunc *> (p);
      return (*function)( x ); 
    }

  };



} // namespace Math
} // namespace ROOT


#endif /* ROOT_Math_GSLMonteFunctionAdapter */

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