FitObjective.h

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// ************************************************************************** //
//
//  BornAgain: simulate and fit scattering at grazing incidence
//
//! @file      Core/Fitting/FitObjective.h
//! @brief     Defines class FitObjective.
//!
//! @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_CORE_FITTING_FITOBJECTIVE_H
#define BORNAGAIN_CORE_FITTING_FITOBJECTIVE_H
 
#include "Core/Fitting/IterationInfo.h"
#include "Core/Fitting/SimDataPair.h"
#include "Device/Intensity/ArrayUtils.h"
#include "Fit/Kernel/MinimizerResult.h"
 
class FitStatus;
class IChiSquaredModule;
class IMetricWrapper;
class ObjectiveMetric;
class PyBuilderCallback;
class PyObserverCallback;
 
//! Holds vector of `SimDataPair`s (experimental data and simulation results) for use in fitting.
//! @ingroup fitting_internal
 
class FitObjective
{
    static simulation_builder_t simulationBuilder(PyBuilderCallback& callback);
 
public:
    FitObjective();
    virtual ~FitObjective();
 
#ifndef SWIG
    void addSimulationAndData(simulation_builder_t builder, const OutputData<double>& data,
                              std::unique_ptr<OutputData<double>> uncertainties,
                              double weight = 1.0);
#endif
    //! Constructs simulation/data pair for later fit.
    //! @param callback: simulation builder capable of producing simulations
    //! @param data: experimental data array
    //! @param weight: weight of dataset in metric calculations
    template <class T>
    void addSimulationAndData(PyBuilderCallback& callback, const T& data, double weight = 1.0)
    {
        addSimulationAndData(simulationBuilder(callback), *ArrayUtils::createData(data), nullptr,
                             weight);
    }
 
    //! Constructs simulation/data pair for later fit.
    //! @param callback: simulation builder capable of producing simulations
    //! @param data: experimental data array
    //! @param uncertainties: data uncertainties array
    //! @param weight: weight of dataset in metric calculations
    template <class T>
    void addSimulationAndData(PyBuilderCallback& callback, const T& data, const T& uncertainties,
                              double weight = 1.0)
    {
        addSimulationAndData(simulationBuilder(callback), *ArrayUtils::createData(data),
                             ArrayUtils::createData(uncertainties), weight);
    }
 
    virtual double evaluate(const Fit::Parameters& params);
 
    virtual std::vector<double> evaluate_residuals(const Fit::Parameters& params);
 
    size_t numberOfFitElements() const;
 
    SimulationResult simulationResult(size_t i_item = 0) const;
    SimulationResult experimentalData(size_t i_item = 0) const;
    SimulationResult uncertaintyData(size_t i_item = 0) const;
    SimulationResult relativeDifference(size_t i_item = 0) const;
    SimulationResult absoluteDifference(size_t i_item = 0) const;
 
    std::vector<double> experimental_array() const;
    std::vector<double> simulation_array() const;
    std::vector<double> uncertainties() const;
    std::vector<double> weights_array() const;
 
    //! Initializes printing to standard output on every_nth fit iteration.
    void initPrint(int every_nth);
 
    //! Initializes observer callback to be called on every_nth fit iteration.
    void initPlot(int every_nth, PyObserverCallback& callback);
 
    IterationInfo iterationInfo() const;
 
    Fit::MinimizerResult minimizerResult() const;
 
    //! Should be explicitely called on last iteration to notify all observers.
    void finalize(const Fit::MinimizerResult& result);
 
    unsigned fitObjectCount() const;
 
    void run_simulations(const Fit::Parameters& params);
 
    void setChiSquaredModule(const IChiSquaredModule& module);
 
    void setObjectiveMetric(const std::string& metric);
    //! Sets objective metric to the FitObjective.
    //! @param metric: metric name
    //! @param norm: metric norm name (defaults to L2-norm)
    void setObjectiveMetric(const std::string& metric, const std::string& norm);
 
    bool containsUncertainties(size_t i_item) const;
    bool allPairsHaveUncertainties() const;
 
    static std::string availableMetricOptions();
 
#ifndef SWIG
    //! Returns a reference to i-th SimDataPair.
    const SimDataPair& dataPair(size_t i_item = 0) const;
 
    void initPlot(int every_nth, fit_observer_t observer);
 
    bool isCompleted() const;
 
    void interruptFitting();
 
    bool isInterrupted() const;
 
    bool isFirstIteration() const;
 
    void setObjectiveMetric(std::unique_ptr<ObjectiveMetric> metric);
#endif // SWIG
 
private:
    typedef std::vector<double> (SimDataPair::*DataPairAccessor)() const;
 
    std::vector<double> composeArray(DataPairAccessor getter) const;
    size_t check_index(size_t index) const;
 
    std::vector<SimDataPair> m_fit_objects;
    std::unique_ptr<IMetricWrapper> m_metric_module;
    std::unique_ptr<FitStatus> m_fit_status;
};
 
#endif // BORNAGAIN_CORE_FITTING_FITOBJECTIVE_H