NumericalDerivative.h

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#ifndef GAUDIMATH_NUMERICALDERIVATIVE_H
#define GAUDIMATH_NUMERICALDERIVATIVE_H 1
// ============================================================================
// Include files
// ============================================================================
// GaudiKernel
// ============================================================================
#include "GaudiKernel/StatusCode.h"
// ============================================================================
// CLHEP
// ============================================================================
#include "CLHEP/GenericFunctions/AbsFunction.hh"
// ============================================================================

#include <memory>

#if defined( __clang__ ) || defined( __CLING__ )
#  pragma clang diagnostic push
#  pragma clang diagnostic ignored "-Winconsistent-missing-override"
#elif defined( __GNUC__ ) && __GNUC__ >= 5
#  pragma GCC diagnostic push
#  pragma GCC diagnostic ignored "-Wsuggest-override"
#endif

namespace Genfun {
  namespace GaudiMathImplementation {
    class GAUDI_API NumericalDerivative : public AbsFunction {
    public:
      enum Type { Central, Forward, Backward };

    public:
      FUNCTION_OBJECT_DEF( NumericalDerivative )

    public:
      NumericalDerivative( const AbsFunction& function, const size_t index, const Type& type = Central );

      NumericalDerivative( const NumericalDerivative& right );

      unsigned int dimensionality() const override { return m_DIM; }

      double operator()( double argument ) const override;
      double operator()( const Argument& argument ) const override;

      bool hasAnalyticDerivative() const override { return true; }

      Derivative partial( unsigned int index ) const override;

    public:
      const AbsFunction& function() const { return *m_function; }
      size_t index() const { return m_index; }
      const Type& type() const { return m_type; }

      const Type& setType( const Type& value );

      double result() const { return m_result; }
      double error() const { return m_error; }

    protected:
      StatusCode Exception( const std::string& message, const StatusCode& sc = StatusCode::FAILURE ) const;

    private:
      // default constructor  is disabled
      NumericalDerivative();
      // assignement operator is disabled
      NumericalDerivative& operator=( const NumericalDerivative& );

    private:
      std::unique_ptr<const AbsFunction> m_function;
      size_t                             m_index;
      size_t                             m_DIM;
      Type                               m_type;
      //
      mutable Argument m_argument;
      mutable double   m_result;
      mutable double   m_error;
    };
    FUNCTION_OBJECT_IMP( NumericalDerivative )

  } // end of namespace GaudiMathImplementation
} // namespace Genfun

#if defined( __clang__ ) || defined( __CLING__ )
#  pragma clang diagnostic pop
#elif defined( __GNUC__ ) && __GNUC__ >= 5
#  pragma GCC diagnostic pop
#endif

// ============================================================================
// The END
// ============================================================================
#endif // GAUDIMATH_NUMERICALDERIVATIVE_H