73 lines
2.1 KiB
C++
73 lines
2.1 KiB
C++
#include <cmath>
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#include <memory>
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#include <vector>
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#include "trigdx/lookup.hpp"
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template <size_t NR_SAMPLES> struct LookupBackend<NR_SAMPLES>::Impl {
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std::vector<float> lookup;
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static constexpr size_t MASK = NR_SAMPLES - 1;
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static constexpr float SCALE = NR_SAMPLES / (2.0f * float(M_PI));
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void init() {
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lookup.resize(NR_SAMPLES);
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for (size_t i = 0; i < NR_SAMPLES; ++i)
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lookup[i] = sinf(i * (2.0f * float(M_PI) / NR_SAMPLES));
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}
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void compute_sinf(size_t n, const float *x, float *s) const {
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for (size_t i = 0; i < n; ++i) {
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size_t idx = static_cast<size_t>(x[i] * SCALE) & MASK;
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s[i] = lookup[idx];
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}
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}
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void compute_cosf(size_t n, const float *x, float *c) const {
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for (size_t i = 0; i < n; ++i) {
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size_t idx = static_cast<size_t>(x[i] * SCALE) & MASK;
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size_t idx_cos = (idx + NR_SAMPLES / 4) & MASK;
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c[i] = lookup[idx_cos];
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}
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}
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void compute_sincosf(size_t n, const float *x, float *s, float *c) const {
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for (size_t i = 0; i < n; ++i) {
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size_t idx = static_cast<size_t>(x[i] * SCALE) & MASK;
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size_t idx_cos = (idx + NR_SAMPLES / 4) & MASK;
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s[i] = lookup[idx];
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c[i] = lookup[idx_cos];
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}
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}
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};
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template <size_t NR_SAMPLES>
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LookupBackend<NR_SAMPLES>::LookupBackend() : impl(std::make_unique<Impl>()) {}
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template <size_t NR_SAMPLES>
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LookupBackend<NR_SAMPLES>::~LookupBackend() = default;
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template <size_t NR_SAMPLES> void LookupBackend<NR_SAMPLES>::init(size_t) {
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impl->init();
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}
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template <size_t NR_SAMPLES>
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void LookupBackend<NR_SAMPLES>::compute_sinf(size_t n, const float *x,
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float *s) const {
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impl->compute_sinf(n, x, s);
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}
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template <size_t NR_SAMPLES>
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void LookupBackend<NR_SAMPLES>::compute_cosf(size_t n, const float *x,
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float *c) const {
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impl->compute_cosf(n, x, c);
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}
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template <size_t NR_SAMPLES>
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void LookupBackend<NR_SAMPLES>::compute_sincosf(size_t n, const float *x,
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float *s, float *c) const {
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impl->compute_sincosf(n, x, s, c);
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}
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template class LookupBackend<16384>;
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template class LookupBackend<32768>;
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