SpectralHankelTransformer.H

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/* Copyright 2019-2020 David Grote
 *
 * This file is part of WarpX.
 *
 * License: BSD-3-Clause-LBNL
 */
#ifndef WARPX_SPECTRALHANKELTRANSFORMER_H_
#define WARPX_SPECTRALHANKELTRANSFORMER_H_
 
#include "HankelTransform.H"
 
#include <AMReX_FArrayBox.H>
 
/* \brief Object that allows to transform the fields back and forth between the
 *  spectral and interpolation grid.
 *
 *  Attributes :
 *  - dht0, dhtm, dhtp : the discrete Hankel transform objects for the modes,
 *     operating along r
*/
 
class SpectralHankelTransformer
{
    public:
 
        SpectralHankelTransformer () = default;
 
        SpectralHankelTransformer (int nr,
                                   int n_rz_azimuthal_modes,
                                   amrex::Real rmax);
 
        void
        ExtractKrArray ();
 
        // Returns an array that holds the kr for all of the modes
        [[nodiscard]] HankelTransform::RealVector const & getKrArray () const {return m_kr;}
 
        // Converts a scalar field from the physical to the spectral space
        void
        PhysicalToSpectral_Scalar (amrex::FArrayBox const & F_physical,
                                   amrex::FArrayBox       & G_spectral);
 
        // Converts a vector field from the physical to the spectral space
        void
        PhysicalToSpectral_Vector (amrex::Box const & box,
                                   amrex::FArrayBox & F_r_physical,
                                   amrex::FArrayBox & F_t_physical,
                                   amrex::FArrayBox & G_p_spectral,
                                   amrex::FArrayBox & G_m_spectral);
 
        // Converts a scalar field from the spectral to the physical space
        void
        SpectralToPhysical_Scalar (amrex::FArrayBox const & G_spectral,
                                   amrex::FArrayBox       & F_physical);
 
        // Converts a vector field from the spectral to the physical space
        void
        SpectralToPhysical_Vector (amrex::Box const & box,
                                   amrex::FArrayBox const & G_p_spectral,
                                   amrex::FArrayBox const & G_m_spectral,
                                   amrex::FArrayBox       & F_r_physical,
                                   amrex::FArrayBox       & F_t_physical);
 
    private:
 
        int m_nr;
        int m_n_rz_azimuthal_modes;
        HankelTransform::RealVector m_kr;
 
        amrex::Vector< std::unique_ptr<HankelTransform> > dht0;
        amrex::Vector< std::unique_ptr<HankelTransform> > dhtm;
        amrex::Vector< std::unique_ptr<HankelTransform> > dhtp;
};
 
#endif