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).
//
// License for the specific language governing rights and limitations under
// 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/BasicUtils/NekManager.hpp>
#include <LibUtilities/BasicUtils/SharedArray.hpp>
#include <LibUtilities/Memory/NekMemoryManager.hpp>
#include <LibUtilities/BasicConst/NektarUnivTypeDefs.hpp>
#include <LibUtilities/BasicConst/NektarUnivConsts.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 boost::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
            virtual ~NekFFTW();
            
            
            
            virtual void v_FFTFwdTrans(Array<OneD,NekDouble> &inarray, Array<OneD,NekDouble> &outarray);
            
            virtual void v_FFTBwdTrans(Array<OneD,NekDouble> &inarray, Array<OneD,NekDouble> &outarray);
            
            
            
        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> phys;
            Array<OneD,NekDouble> coef;

            Array<OneD,NekDouble> m_wsp;     // Workspace area for transforms

            fftw_plan plan_backward;         // plan to execute a backward FFT in FFTW
            fftw_plan 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);
            
            

        private:
        };

    }//end namespace LibUtilities
}//end of namespace Nektar
#endif //NEKTAR_LIB_UTILIITIES_FFT_NEKFFTW_H