BasicFCN.h

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// @(#)root/mathcore:$Id$
// Author: L. Moneta 25 Nov 2014
 
/**********************************************************************
 *                                                                    *
 * Copyright (c) 2006  LCG ROOT Math Team, CERN/PH-SFT                *
 *                                                                    *
 *                                                                    *
 **********************************************************************/
 
// Header file for class BasicFCN
 
#ifndef ROOT_Fit_BasicFCN
#define ROOT_Fit_BasicFCN
 
#include "Math/FitMethodFunction.h"
 
#include "Math/IParamFunction.h"
 
#include "Math/IParamFunctionfwd.h"
 
#include <memory>
 
 
 
namespace ROOT {
 
 
   namespace Fit {
 
 
 
//___________________________________________________________________________________
/**
   BasicFCN class: base class  for the objective functions used in the fits
   It has a reference to the data and the model function used in the fit.
   It cannot be instantiated but constructed from the derived classes
*/
template<class DerivFunType, class ModelFunType, class DataType>
class BasicFCN : public ::ROOT::Math::BasicFitMethodFunction<DerivFunType> {
 
protected:
 
   typedef typename ModelFunType::BackendType T;
 
   typedef  ::ROOT::Math::BasicFitMethodFunction<DerivFunType> BaseObjFunction;
   typedef typename  BaseObjFunction::BaseFunction BaseFunction;
 
   typedef  ::ROOT::Math::IParamMultiFunctionTempl<T> IModelFunction;
   typedef  ::ROOT::Math::IParametricGradFunctionMultiDimTempl<T> IGradModelFunction;
 
   /**
      Constructor from data set  and model function
   */
   BasicFCN (const std::shared_ptr<DataType> & data, const std::shared_ptr<IModelFunction> & func) :
      BaseObjFunction(func->NPar(), data->Size() ),
      fData(data),
      fFunc(func)
   { }
 
 
 
   /**
      Destructor (no operations)
   */
   virtual ~BasicFCN ()  {}
 
public:
 
 
   /// access to const reference to the data
   virtual const DataType & Data() const { return *fData; }
 
   /// access to data pointer
   std::shared_ptr<DataType> DataPtr() const { return fData; }
 
   /// access to const reference to the model function
   virtual const IModelFunction & ModelFunction() const { return *fFunc; }
 
   /// access to function pointer
   std::shared_ptr<IModelFunction> ModelFunctionPtr() const { return fFunc; }
 
   /// flag to indicate if can compute Hessian
   virtual bool HasHessian() const {
      if (!BaseObjFunction::IsAGradFCN()) return false;
      auto gfunc = dynamic_cast<const IGradModelFunction *>( fFunc.get());
      if (!gfunc) return false;
      return gfunc->HasParameterHessian();
   }
 
 
 
 
protected:
 
 
   /// Set the data pointer
   void SetData(const std::shared_ptr<DataType> & data) { fData = data; }
 
      /// Set the function pointer
   void SetModelFunction(const std::shared_ptr<IModelFunction> & func) { fFunc = func; }
 
 
   std::shared_ptr<DataType>  fData;
   std::shared_ptr<IModelFunction>  fFunc;
 
 
 
};
 
 
 
   } // end namespace Fit
 
} // end namespace ROOT
 
 
#endif /* ROOT_Fit_BasicFCN */