MatrixRTCoefficients.h

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// ************************************************************************** //
//
//  BornAgain: simulate and fit scattering at grazing incidence
//
//! @file      Sample/RT/MatrixRTCoefficients.h
//! @brief    Defines class MatrixRTCoefficients.
//!
//! @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_RT_MATRIXRTCOEFFICIENTS_H
#define BORNAGAIN_CORE_RT_MATRIXRTCOEFFICIENTS_H
 
#include "Sample/RT/ILayerRTCoefficients.h"
 
//! Specular reflection and transmission coefficients in a layer in case
//! of 2x2 matrix interactions between the layers and the scattered particle.
//! @ingroup algorithms_internal
 
class MatrixRTCoefficients : public ILayerRTCoefficients
{
public:
    MatrixRTCoefficients() : m_kt(0.0) {}
    virtual ~MatrixRTCoefficients() {}
 
    virtual MatrixRTCoefficients* clone() const;
 
    //! The following functions return the transmitted and reflected amplitudes
    //! for different incoming beam polarizations and eigenmodes
    virtual Eigen::Vector2cd T1plus() const;
    virtual Eigen::Vector2cd R1plus() const;
    virtual Eigen::Vector2cd T2plus() const;
    virtual Eigen::Vector2cd R2plus() const;
    virtual Eigen::Vector2cd T1min() const;
    virtual Eigen::Vector2cd R1min() const;
    virtual Eigen::Vector2cd T2min() const;
    virtual Eigen::Vector2cd R2min() const;
    //! Returns z-part of the two wavevector eigenmodes
    virtual Eigen::Vector2cd getKz() const { return kz; }
 
    void calculateTRMatrices();
    void calculateTRWithoutMagnetization();
    void initializeBottomLayerPhiPsi();
 
    // NOTE: exceptionally, this class has member variables without prefix m_
    Eigen::Vector2cd kz;             //!< z-part of the two wavevector eigenmodes
    Eigen::Vector2cd lambda;         //!< positive eigenvalues of transfer matrix
    Eigen::Vector4cd phi_psi_plus;   //!< boundary values for up-polarization
    Eigen::Vector4cd phi_psi_min;    //!< boundary values for down-polarization
    Eigen::Matrix4cd T1m;            //!< matrix selecting the transmitted part of
                                     //!< the first eigenmode
    Eigen::Matrix4cd R1m;            //!< matrix selecting the reflected part of
                                     //!< the first eigenmode
    Eigen::Matrix4cd T2m;            //!< matrix selecting the transmitted part of
                                     //!< the second eigenmode
    Eigen::Matrix4cd R2m;            //!< matrix selecting the reflected part of
                                     //!< the second eigenmode
    Eigen::Matrix2cd m_scatt_matrix; //!< scattering matrix
    complex_t m_a;                   //!< polarization independent part of scattering matrix
    complex_t m_b_mag;               //!< magnitude of magnetic interaction term
    complex_t m_bz;                  //!< z-part of magnetic interaction term
    double m_kt;                     //!< wavevector length times thickness of layer for use when
                                     //!< lambda=0
};
 
#endif // BORNAGAIN_CORE_RT_MATRIXRTCOEFFICIENTS_H