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armadillo-code/include/armadillo_bits/op_fft_meat.hpp
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// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------
//! \addtogroup op_fft
//! @{
#if defined(ARMA_USE_FFTW3)
template<typename cx_type, bool inverse>
class fft_engine_wrapper
{
public:
static constexpr uword threshold = 512;
fft_engine_kissfft<cx_type,inverse>* worker_kissfft = nullptr;
fft_engine_fftw3 <cx_type,inverse>* worker_fftw3 = nullptr;
inline
~fft_engine_wrapper()
{
arma_debug_sigprint();
if(worker_kissfft != nullptr) { delete worker_kissfft; }
if(worker_fftw3 != nullptr) { delete worker_fftw3; }
}
inline
fft_engine_wrapper(const uword N_samples, const uword N_exec)
{
arma_debug_sigprint();
const bool use_fftw3 = N_samples >= (threshold / N_exec);
worker_kissfft = (use_fftw3 == false) ? new fft_engine_kissfft<cx_type,inverse>(N_samples) : nullptr;
worker_fftw3 = (use_fftw3 == true ) ? new fft_engine_fftw3 <cx_type,inverse>(N_samples) : nullptr;
}
inline
void
run(cx_type* Y, const cx_type* X)
{
arma_debug_sigprint();
if(worker_kissfft != nullptr) { (*worker_kissfft).run(Y,X); }
else if(worker_fftw3 != nullptr) { (*worker_fftw3).run(Y,X); }
}
};
#endif
//
// op_fft_real
template<typename T1>
inline
void
op_fft_real::apply( Mat< std::complex<typename T1::pod_type> >& out, const mtOp<std::complex<typename T1::pod_type>,T1,op_fft_real>& in )
{
arma_debug_sigprint();
typedef typename T1::pod_type in_eT;
typedef typename std::complex<in_eT> out_eT;
// no need to worry about aliasing, as we're going from a real object to complex complex, which by definition cannot alias
const quasi_unwrap<T1> U(in.m);
const Mat<in_eT>& X = U.M;
const uword n_rows = X.n_rows;
const uword n_cols = X.n_cols;
const uword n_elem = X.n_elem;
const bool is_vec = ( (n_rows == 1) || (n_cols == 1) );
const uword N_orig = (is_vec) ? n_elem : n_rows;
const uword N_user = (in.aux_uword_b == 0) ? in.aux_uword_a : N_orig;
#if defined(ARMA_USE_FFTW3)
const uword N_exec = (is_vec) ? uword(1) : n_cols;
fft_engine_wrapper<out_eT,false> worker(N_user, N_exec);
#else
fft_engine_kissfft<out_eT,false> worker(N_user);
#endif
if(is_vec)
{
(n_cols == 1) ? out.set_size(N_user, 1) : out.set_size(1, N_user);
if( (out.n_elem == 0) || (N_orig == 0) ) { out.zeros(); return; }
if( (N_user == 1) && (N_orig >= 1) ) { out[0] = out_eT( X[0] ); return; }
podarray<out_eT> data(N_user, arma_zeros_indicator());
out_eT* data_mem = data.memptr();
const in_eT* X_mem = X.memptr();
const uword N = (std::min)(N_user, N_orig);
for(uword i=0; i < N; ++i) { data_mem[i].real(X_mem[i]); }
worker.run( out.memptr(), data_mem );
}
else
{
// process each column separately
out.set_size(N_user, n_cols);
if( (out.n_elem == 0) || (N_orig == 0) ) { out.zeros(); return; }
if( (N_user == 1) && (N_orig >= 1) )
{
for(uword col=0; col < n_cols; ++col) { out.at(0,col).real( X.at(0,col) ); }
return;
}
podarray<out_eT> data(N_user, arma_zeros_indicator());
out_eT* data_mem = data.memptr();
const uword N = (std::min)(N_user, N_orig);
for(uword col=0; col < n_cols; ++col)
{
for(uword i=0; i < N; ++i) { data_mem[i].real( X.at(i, col) ); }
worker.run( out.colptr(col), data_mem );
}
}
}
//
// op_fft_cx
template<typename T1>
inline
void
op_fft_cx::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_fft_cx>& in)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
const quasi_unwrap<T1> U(in.m);
if(U.is_alias(out))
{
Mat<eT> tmp;
op_fft_cx::apply_noalias<eT,false>(tmp, U.M, in.aux_uword_a, in.aux_uword_b);
out.steal_mem(tmp);
}
else
{
op_fft_cx::apply_noalias<eT,false>(out, U.M, in.aux_uword_a, in.aux_uword_b);
}
}
template<typename eT, bool inverse>
inline
void
op_fft_cx::apply_noalias(Mat<eT>& out, const Mat<eT>& X, const uword a, const uword b)
{
arma_debug_sigprint();
const uword n_rows = X.n_rows;
const uword n_cols = X.n_cols;
const uword n_elem = X.n_elem;
const bool is_vec = ( (n_rows == 1) || (n_cols == 1) );
const uword N_orig = (is_vec) ? n_elem : n_rows;
const uword N_user = (b == 0) ? a : N_orig;
#if defined(ARMA_USE_FFTW3)
const uword N_exec = (is_vec) ? uword(1) : n_cols;
fft_engine_wrapper<eT,inverse> worker(N_user, N_exec);
#else
fft_engine_kissfft<eT,inverse> worker(N_user);
#endif
if(is_vec)
{
(n_cols == 1) ? out.set_size(N_user, 1) : out.set_size(1, N_user);
if( (out.n_elem == 0) || (N_orig == 0) ) { out.zeros(); return; }
if( (N_user == 1) && (N_orig >= 1) ) { out[0] = X[0]; return; }
if(N_user > N_orig)
{
podarray<eT> data(N_user);
eT* data_mem = data.memptr();
arrayops::fill_zeros( &data_mem[N_orig], (N_user - N_orig) );
arrayops::copy(data_mem, X.memptr(), (std::min)(N_user, N_orig));
worker.run( out.memptr(), data_mem );
}
else
{
worker.run( out.memptr(), X.memptr() );
}
}
else
{
// process each column separately
out.set_size(N_user, n_cols);
if( (out.n_elem == 0) || (N_orig == 0) ) { out.zeros(); return; }
if( (N_user == 1) && (N_orig >= 1) )
{
for(uword col=0; col < n_cols; ++col) { out.at(0,col) = X.at(0,col); }
return;
}
if(N_user > N_orig)
{
podarray<eT> data(N_user);
eT* data_mem = data.memptr();
arrayops::fill_zeros( &data_mem[N_orig], (N_user - N_orig) );
const uword N = (std::min)(N_user, N_orig);
for(uword col=0; col < n_cols; ++col)
{
arrayops::copy(data_mem, X.colptr(col), N);
worker.run( out.colptr(col), data_mem );
}
}
else
{
for(uword col=0; col < n_cols; ++col)
{
worker.run( out.colptr(col), X.colptr(col) );
}
}
}
// correct the scaling for the inverse transform
if(inverse)
{
typedef typename get_pod_type<eT>::result T;
const T k = T(1) / T(N_user);
eT* out_mem = out.memptr();
const uword out_n_elem = out.n_elem;
for(uword i=0; i < out_n_elem; ++i) { out_mem[i] *= k; }
}
}
//
// op_ifft_cx
template<typename T1>
inline
void
op_ifft_cx::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_ifft_cx>& in)
{
arma_debug_sigprint();
typedef typename T1::elem_type eT;
const quasi_unwrap<T1> U(in.m);
if(U.is_alias(out))
{
Mat<eT> tmp;
op_fft_cx::apply_noalias<eT,true>(tmp, U.M, in.aux_uword_a, in.aux_uword_b);
out.steal_mem(tmp);
}
else
{
op_fft_cx::apply_noalias<eT,true>(out, U.M, in.aux_uword_a, in.aux_uword_b);
}
}
//! @}