NekFFTW.h

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///////////////////////////////////////////////////////////////////////////////
//
// File: NekFFTW.h
//
// For more information, please see: http://www.nektar.info
//
// The MIT License
//
// Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
// Department of Aeronautics, Imperial College London (UK), and Scientific
// Computing and Imaging Institute, University of Utah (USA).
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
// Description: Header file for the wrapper around FFTW library
//
///////////////////////////////////////////////////////////////////////////////
 
#ifndef NEKTAR_LIB_UTILIITIES_FFT_NEKFFTW_H
#define NEKTAR_LIB_UTILIITIES_FFT_NEKFFTW_H
 
#include <LibUtilities/FFT/NektarFFT.h>
 
#include <LibUtilities/BasicConst/NektarUnivConsts.hpp>
#include <LibUtilities/BasicConst/NektarUnivTypeDefs.hpp>
#include <LibUtilities/BasicUtils/NekManager.hpp>
#include <LibUtilities/BasicUtils/SharedArray.hpp>
#include <LibUtilities/Memory/NekMemoryManager.hpp>
 
#include <fftw3.h>
 
namespace Nektar
{
template <typename Dim, typename DataType> class Array;
 
namespace LibUtilities
{
class NekFFTW;
 
// A shared pointer to the NekFFTW object
typedef std::shared_ptr<NekFFTW> NekFFTWSharedPtr;
 
class NekFFTW : public NektarFFT
{
public:
    /// Creates an instance of this class
    static NektarFFTSharedPtr create(int N)
    {
        return MemoryManager<NekFFTW>::AllocateSharedPtr(N);
    }
 
    /// Name of class
    static std::string className;
 
    // constructor (initialisation of the FFTW planes and fill up the m_FFTW_w
    // vector)
    NekFFTW(int N);
 
    // Distructor
    ~NekFFTW() override;
 
protected:
    Array<OneD, NekDouble>
        m_FFTW_w; // weights to convert arrays form Nektar++ to FFTW format
    Array<OneD, NekDouble>
        m_FFTW_w_inv; // weights to convert arrays from FFTW to Nektar++ format
 
    Array<OneD, NekDouble> m_phys;
    Array<OneD, NekDouble> m_coef;
 
    Array<OneD, NekDouble> m_wsp; // Workspace area for transforms
 
    fftw_plan m_plan_backward; // plan to execute a backward FFT in FFTW
    fftw_plan m_plan_forward;  // plan to execute a forward FFT in FFTW
    /**
     * Reshuffling routines to put the coefficients in Nektar++/FFTW format.
     * The routines take as an input the number of points N, the vector of
     * coeffcients and the vector containing the weights of the numerical
     * integration. The routines modify directly the coef vector.
     */
    void Reshuffle_FFTW2Nek(Array<OneD, NekDouble> &coef);
 
    void Reshuffle_Nek2FFTW(Array<OneD, NekDouble> &coef);
 
    void v_FFTFwdTrans(Array<OneD, NekDouble> &inarray,
                       Array<OneD, NekDouble> &outarray) override;
 
    void v_FFTBwdTrans(Array<OneD, NekDouble> &inarray,
                       Array<OneD, NekDouble> &outarray) override;
 
private:
};
 
} // end namespace LibUtilities
} // end of namespace Nektar
#endif // NEKTAR_LIB_UTILIITIES_FFT_NEKFFTW_H