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/*
* Copyright (c) 2002, 2017 Jens Keiner, Stefan Kunis, Daniel Potts
*
* This program 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 2 of the License, or (at your option) any later
* version.
*
* This program 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
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/** @defgroup nnfft NNFFT - Nonequispaced in time and frequency FFT
* Direct and fast computation of the discrete nonequispaced in time and
* frequency Fourier transform.
* @{
*/
/*! \struct nnfft_plan
* NNFFT transform plan
*/
/*! \fn nnfft_init(nnfft_plan *ths_plan, int d, int N_total, int M_total, int *N)
* Creates a transform plan.
*
* \arg ths_plan The plan for the transform
* \arg d The dimension
* \arg N_total The number of nodes \f$v\f$
* \arg M_total The number of nodes \f$x\f$
* \arg N The bandwidth \f$N\f$
*
* \author Tobias Knopp
*/
/*! \fn void nnfft_init_guru(nnfft_plan *ths_plan, int d, int N_total, int M_total, int *N, int *N1, int m, unsigned nnfft_flags)
* Creates a transform plan.
*
* \arg ths_plan The plan for the transform
* \arg d The dimension
* \arg N_total The number of nodes \f$v\f$
* \arg M_total The number of nodes \f$x\f$
* \arg N The bandwidth \f$N\f$
* \arg N1 The oversampled bandwidth \f$N\f$
* \arg m The cut-off parameter
* \arg nnfft_flags The flags
*
* \author Tobias Knopp
*/
/*! \fn void nnfft_direct_trafo(nnfft_plan *ths_plan)
* Executes a direct NNDFT, i.e. computes for \f$j=0,...,M_{total}-1\f$
* \f[
* f(x_j) = \sum_{k = 0}^{N_{total}-1} \hat{f}(v_k) {\rm e}^{-2 \pi
* \mbox{\rm\scriptsize i} v_k x_j \odot N}
* \f]
*
* \arg ths_plan The plan
*
* \author Tobias Knopp
*/
/*! \fn void nnfft_direct_adjoint(nnfft_plan *ths_plan)
* Executes a direct adjoint NNDFT, i.e. computes for \f$k=0,...,N_{total}-1\f$
* \f[
* \hat{f}(v_k) = \sum_{j = 0}^{M_{total}-1} f(x_j) {\rm e}^{2 \pi
* \mbox{\rm\scriptsize i} v_k x_j \odot N}
* \f]
*
* \arg ths_plan The plan
*
* \author Tobias Knopp
*/
/*! \fn void nnfft_trafo(nnfft_plan *ths_plan)
* Executes a NNFFT, i.e. computes for \f$j=0,...,M_{total}-1\f$
* \f[
* f(x_j) = \sum_{k = 0}^{N_{total}-1} \hat{f}(v_k) {\rm e}^{-2 \pi
* \mbox{\rm\scriptsize i} v_k x_j \odot N}
* \f]
*
* \arg ths_plan The plan
*
* \author Tobias Knopp
*/
/*! \fn void nnfft_adjoint(nnfft_plan *ths_plan)
* Executes a adjoint NNFFT, i.e. computes for \f$k=0,...,N_{total}-1\f$
* \f[
* \hat{f}(v_k) = \sum_{j = 0}^{M_{tota}l-1} f(x_j) {\rm e}^{2 \pi
* \mbox{\rm\scriptsize i} v_k x_j \odot N}
* \f]
*
* \arg ths_plan The plan
*
* \author Tobias Knopp
*/
/*! \fn void nnfft_precompute_lin_psi(nnfft_plan *ths_plan)
* Precomputation for a transform plan.
*
* \arg ths_plan The pointer to a nfft plan
*
* \author Tobias Knopp
*
* precomputes equally spaced values of the window function psi
*
* if PRE_LIN_PSI is set the application program has to call this routine
*/
/*! \fn void nnfft_precompute_psi(nnfft_plan *ths_plan)
* Precomputation for a transform plan.
*
* \arg ths_plan The pointer to a nfft plan
*
* \author Tobias Knopp
*
* precomputes the values of the window function psi in a tensor product form
*
* if PRE_PSI is set the application program has to call this routine after
* setting the nodes x
*/
/*! \fn void nnfft_precompute_full_psi(nnfft_plan *ths_plan)
* Precomputation for a transform plan.
*
* \arg ths_plan The pointer to a nfft plan
*
* \author Tobias Knopp
*
* precomputes the values of the window function psi and their indices in
* non tensor product form
*
* if PRE_FULL_PSI is set the application program has to call this routine
* after setting the nodes x
*/
/*! \fn void nnfft_precompute_phi_hut(nnfft_plan *ths_plan)
* Precomputation for a transform plan.
*
* \arg ths_plan The pointer to a nfft plan
*
* \author Tobias Knopp
*
* precomputes the values of the fourier transformed window function, i.e. phi_hut
*
* if PRE_PHI_HUT is set the application program has to call this routine
* after setting the nodes v
*/
/*! \fn void nnfft_finalize(nnfft_plan *ths_plan)
* Destroys a plan.
*
* \arg ths_plan The plan
*
* \author Tobias Knopp
*/
/*! \def MALLOC_V
* If this flag is set, (de)allocation of the frequency node vector is done.
*
* \see nnfft_init
* \see nnfft_init_guru
* \see nnfft_finalize
* \author Tobias Knopp
*/
/** @}
*/
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