RootResidualFunction.h

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// ************************************************************************** //
//
//  BornAgain: simulate and fit scattering at grazing incidence
//
//! @file      Fit/RootAdapter/RootResidualFunction.h
//! @brief     Declares class RootResidualFunction.
//!
//! @homepage  http://www.bornagainproject.org
//! @license   GNU General Public License v3 or higher (see COPYING)
//! @copyright Forschungszentrum Jülich GmbH 2018
//! @authors   Scientific Computing Group at MLZ (see CITATION, AUTHORS)
//
// ************************************************************************** //
 
#ifndef BORNAGAIN_FIT_ROOTADAPTER_ROOTRESIDUALFUNCTION_H
#define BORNAGAIN_FIT_ROOTADAPTER_ROOTRESIDUALFUNCTION_H
 
#include "Fit/Kernel/KernelTypes.h"
 
#ifdef _WIN32
#include <Math/FitMethodFunction.h>
#else
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#include <Math/FitMethodFunction.h>
#pragma GCC diagnostic pop
#endif
 
//! Minimizer function with access to single data element residuals,
//! required by Fumili2 and GSLMultiMin minimizers.
 
class RootResidualFunction : public ROOT::Math::FitMethodFunction
{
public:
    typedef ROOT::Math::BasicFitMethodFunction<ROOT::Math::IMultiGenFunction>::Type_t Type_t;
 
    //! Constructs RootResidualFunction
    RootResidualFunction(scalar_function_t objective_fun, gradient_function_t gradient_fun,
                         size_t npars, size_t ndatasize);
 
    Type_t Type() const override;
 
    ROOT::Math::IMultiGenFunction* Clone() const override;
 
    //! Evaluation of single data element residual. Will be called by ROOT minimizer.
    double DataElement(const double* pars, unsigned int index,
                       double* gradients = 0) const override;
 
private:
    //! evaluation of chi2
    double DoEval(const double* pars) const override;
 
    scalar_function_t m_objective_fun;  //!< User function to get value to minimizer.
    gradient_function_t m_gradient_fun; //!< User function to get residual and gradients.
    size_t m_npars;
    size_t m_datasize;
};
 
#endif // BORNAGAIN_FIT_ROOTADAPTER_ROOTRESIDUALFUNCTION_H