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add C++11constexpr fft

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Stockham DIT fft algorithm written in C++11constexpr
This commit is contained in:
lpha-z 2016-09-12 18:13:01 +09:00
parent f08464943f
commit e6af368c77
9 changed files with 575 additions and 169 deletions
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48
sprout/numeric/fft/ifft.hpp
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@ -8,51 +8,9 @@
#ifndef SPROUT_NUMERIC_FFT_IFFT_HPP
#define SPROUT_NUMERIC_FFT_IFFT_HPP
#include <iterator>
#include <sprout/config.hpp>
#include <sprout/complex.hpp>
#include <sprout/algorithm/cxx14/transform.hpp>
#include <sprout/numeric/fft/fft.hpp>
namespace sprout {
namespace detail {
struct conj_value {
public:
template<typename Complex>
SPROUT_CONSTEXPR Complex operator()(Complex const& x) const {
return conj(x);
}
};
template<typename Size>
struct conj_div_value {
private:
Size n_;
public:
explicit SPROUT_CONSTEXPR conj_div_value(Size n)
: n_(n)
{}
template<typename Complex>
SPROUT_CONSTEXPR Complex operator()(Complex const& x) const {
return conj(x) / typename Complex::value_type(n_);
}
};
template<typename Size>
SPROUT_CONSTEXPR sprout::detail::conj_div_value<Size>
conj_div(Size n) {
return sprout::detail::conj_div_value<Size>(n);
}
} // namespace detail
//
// ifft
//
template<typename RandomAccessIterator>
inline SPROUT_CXX14_CONSTEXPR void
ifft(RandomAccessIterator first, RandomAccessIterator last) {
sprout::transform(first, last, first, sprout::detail::conj_value());
sprout::fft(first, last);
sprout::transform(first, last, first, sprout::detail::conj_div(last - first));
}
} // namespace sprout
#include <sprout/numeric/fft/fixed/ifft.hpp>
#include <sprout/numeric/fft/fit/ifft.hpp>
#include <sprout/numeric/fft/cxx14/ifft.hpp>
#endif // #ifndef SPROUT_NUMERIC_FFT_IFFT_HPP