Function fft_c2r

src/backend/oneapi/fft.cpp:244–275

template<typename Tr, typename Tc>
Array<Tr> fft_c2r(const Array<Tc> &in, const dim4 &odims, const int rank) {
    const dim4 idims    = in.dims();
    const dim4 istrides = in.strides();
    Array<Tr> out       = createEmptyArray<Tr>(odims);
    const dim4 ostrides = out.strides();

    constexpr bool is_single = std::is_same_v<Tr, float>;
    constexpr auto precision = (is_single)
                                   ? ::oneapi::mkl::dft::precision::SINGLE
                                   : ::oneapi::mkl::dft::precision::DOUBLE;
    using desc_ty =
        ::oneapi::mkl::dft::descriptor<precision,
                                       ::oneapi::mkl::dft::domain::REAL>;

    std::vector<std::int64_t> fft_input_strides =
        computeStrides(rank, istrides, in.getOffset());
    std::vector<std::int64_t> fft_output_strides =
        computeStrides(rank, ostrides, out.getOffset());

    int batch = 1;
    for (int i = rank; i < 4; i++) { batch *= odims[i]; }

    const bool isInPlace = false;
    PlanType descP = findPlan<precision, ::oneapi::mkl::dft::domain::REAL>(
        rank, isInPlace, odims.get(), fft_input_strides.data(), ostrides[rank],
        fft_output_strides.data(), istrides[rank], batch);

    desc_ty *desc = (desc_ty *)descP.get();

    ::oneapi::mkl::dft::compute_backward(*desc, *in.get(), *out.get());
    return out;
}

#define INSTANTIATE(T) \
    template void fft_inplace<T>(Array<T> &, const int, const bool);