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https://github.com/bolero-MURAKAMI/Sprout.git
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59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
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/*=============================================================================
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Copyright (c) 2011-2014 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_NUMERIC_FFT_IFFT_HPP
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#define SPROUT_NUMERIC_FFT_IFFT_HPP
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#include <iterator>
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#include <sprout/config.hpp>
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#include <sprout/complex.hpp>
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#include <sprout/algorithm/cxx14/transform.hpp>
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#include <sprout/numeric/fft/fft.hpp>
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namespace sprout {
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namespace detail {
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struct conj_value {
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public:
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template<typename Complex>
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SPROUT_CONSTEXPR Complex operator()(Complex const& x) const {
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return conj(x);
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}
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};
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template<typename Size>
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struct conj_div_value {
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private:
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Size n_;
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public:
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explicit SPROUT_CONSTEXPR conj_div_value(Size n)
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: n_(n)
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{}
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template<typename Complex>
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SPROUT_CONSTEXPR Complex operator()(Complex const& x) const {
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return conj(x) / typename Complex::value_type(n_);
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}
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};
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template<typename Size>
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SPROUT_CONSTEXPR sprout::detail::conj_div_value<Size>
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conj_div(Size n) {
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return sprout::detail::conj_div_value<Size>(n);
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}
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} // namespace detail
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//
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// ifft
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//
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template<typename RandomAccessIterator>
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inline SPROUT_CXX14_CONSTEXPR void
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ifft(RandomAccessIterator first, RandomAccessIterator last) {
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sprout::transform(first, last, first, sprout::detail::conj_value());
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sprout::fft(first, last);
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sprout::transform(first, last, first, sprout::detail::conj_div(last - first));
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_NUMERIC_FFT_IFFT_HPP
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