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muSpectre_proto/src/system/fftw_engine_r2c.hh
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fftw_engine_r2c.hh
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/**
* file fftw_engine_r2c.hh
*
* @author Till Junge <till.junge@epfl.ch>
*
* @date 13 May 2017
*
* @brief implementation of fft_engine usinge r2c and c2r transforms
*
* @section LICENCE
*
* Copyright (C) 2017 Till Junge
*
* µSpectre is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, either version 3, or (at
* your option) any later version.
*
* µSpectre is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Emacs; see the file COPYING. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "system/fft_engine.hh"
#include <fftw3.h>
#include <tuple>
#ifndef FFTW_ENGINE_R2C_H
#define FFTW_ENGINE_R2C_H
namespace muSpectre {
template <Dim_t DimS, Dim_t DimM>
class FFTW_EngineR2C: public FFT_Engine<DimS, DimM> {
public:
using Ccoord = Ccoord_t<DimS>;
FFTW_EngineR2C(Ccoord nb_pixels, FFT_PlanFlags flags);
virtual ~FFTW_EngineR2C();
virtual Real * convolve(const Real * const Ghat, const Real * const arr) override {if (true || Ghat == arr){}; return nullptr;};
virtual void convolve (const Real * const Ghat, const Real * const in, Real * out) override;
protected:
virtual void init(FFT_PlanFlags flags) override;
class index_iterator{
public:
index_iterator(const FFTW_EngineR2C & parent, bool begin=true);
// tuple contains index in real-row-major-array, then complex-row-major-array
inline std::tuple<size_t, size_t> operator*();
inline index_iterator & operator++();
inline bool operator !=(const index_iterator & other) const;
protected:
const FFTW_EngineR2C & parent;
size_t index;
Ccoord full_strides;
Ccoord half_strides;
};
index_iterator begin();
index_iterator end();
size_t nb_hermitian;
fftw_complex * work_space;
fftw_plan plan_fft;
fftw_plan plan_ifft;
};
//----------------------------------------------------------------------------//
template<Dim_t DimS, Dim_t DimM>
bool FFTW_EngineR2C<DimS, DimM>::index_iterator::operator!=(const index_iterator & other) const {
return this->index != other.index;
}
//----------------------------------------------------------------------------//
template<Dim_t DimS, Dim_t DimM>
std::tuple<size_t, size_t> FFTW_EngineR2C<DimS, DimM>::index_iterator::operator*() {
size_t tmp_index = this->index;
Ccoord actual_index;
for (Dim_t i = DimS-1; i > 0; --i) {
actual_index[i] = tmp_index%half_strides[i-1];
tmp_index/=half_strides[i-1];
}
actual_index[0] = tmp_index;
return {std::inner_product(full_strides.begin(), full_strides.end(),
actual_index.begin(), 0), this->index};
}
//----------------------------------------------------------------------------//
template<Dim_t DimS, Dim_t DimM>
typename FFTW_EngineR2C<DimS, DimM>::index_iterator &
FFTW_EngineR2C<DimS, DimM>::index_iterator::operator++() {
this->index++;
return *this;
}
} // muSpectre
#endif /* FFTW_ENGINE_R2C_H */
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