277 lines
11 KiB
C++
277 lines
11 KiB
C++
#include <algorithm>
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#include <cmath>
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#include <vector>
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#include <xsimd/xsimd.hpp>
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#include "trigdx/lookup_xsimd.hpp"
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template <std::size_t NR_SAMPLES> struct lookup_table {
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static constexpr std::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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static constexpr float PI_FRAC = 2.0f * M_PIf32 / NR_SAMPLES;
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static constexpr float TERM1 = 1.0f; // 1
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static constexpr float TERM2 = 0.5f; // 1/2!
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static constexpr float TERM3 = 1.0f / 6.0f; // 1/3!
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static constexpr float TERM4 = 1.0f / 24.0f; // 1/4!
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constexpr lookup_table() : sin_values{}, cos_values{} {
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for (uint_fast32_t i = 0; i < NR_SAMPLES; i++) {
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sin_values[i] = sinf(i * PI_FRAC);
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cos_values[i] = cosf(i * PI_FRAC);
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}
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}
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std::array<float, NR_SAMPLES> cos_values;
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std::array<float, NR_SAMPLES> sin_values;
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};
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template <std::size_t NR_SAMPLES> struct cosf_dispatcher {
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constexpr cosf_dispatcher() : lookup_table_(){};
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template <class Tag, class Arch>
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void operator()(Arch, const size_t n, const float *a, float *c, Tag) const {
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using b_type = xsimd::batch<float, Arch>;
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using m_type = xsimd::batch<int32_t, Arch>;
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constexpr uint_fast32_t VL = b_type::size;
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const uint_fast32_t VS = n - n % VL;
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const uint_fast32_t Q_PI = NR_SAMPLES / 4U;
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const b_type scale = b_type::broadcast(lookup_table_.SCALE);
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const b_type pi_frac = b_type::broadcast(lookup_table_.PI_FRAC);
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const m_type mask = m_type::broadcast(lookup_table_.MASK);
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const b_type term1 = b_type::broadcast(lookup_table_.TERM1); // 1
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const b_type term2 = b_type::broadcast(lookup_table_.TERM2); // 1/2!
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const b_type term3 = b_type::broadcast(lookup_table_.TERM3); // 1/3!
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const b_type term4 = b_type::broadcast(lookup_table_.TERM4); // 1/4!
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const m_type quarter_pi = m_type::broadcast(Q_PI);
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uint_fast32_t i;
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for (i = 0; i < VS; i += VL) {
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const b_type vx = b_type::load(a + i, Tag());
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const b_type scaled = xsimd::mul(vx, scale);
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m_type idx = xsimd::to_int(scaled);
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const b_type f_idx = xsimd::to_float(idx);
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idx = xsimd::bitwise_and(idx, mask);
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b_type cosv = b_type::gather(lookup_table_.cos_values.data(), idx);
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b_type sinv = b_type::gather(lookup_table_.sin_values.data(), idx);
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const b_type dx = xsimd::sub(vx, xsimd::mul(f_idx, pi_frac));
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const b_type dx2 = xsimd::mul(dx, dx);
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const b_type dx3 = xsimd::mul(dx2, dx);
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const b_type dx4 = xsimd::mul(dx2, dx);
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const b_type t2 = xsimd::mul(dx2, term2);
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const b_type t3 = xsimd::mul(dx3, term3);
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const b_type t4 = xsimd::mul(dx4, term3);
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const b_type cosdx = xsimd::add(xsimd::sub(term1, t2), t4);
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const b_type sindx = xsimd::sub(dx, t3);
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cosv = xsimd::sub(xsimd::mul(cosv, cosdx), xsimd::mul(sinv, sindx));
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cosv.store(c + i, Tag());
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}
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for (; i < n; i++) {
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std::size_t idx = static_cast<std::size_t>(a[i] * lookup_table_.SCALE);
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std::size_t masked = idx & lookup_table_.MASK;
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const float cosv = lookup_table_.cos_values[masked];
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const float sinv = lookup_table_.sin_values[masked];
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const float dx = a[i] - idx * lookup_table_.PI_FRAC;
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const float dx2 = dx * dx;
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const float dx3 = dx2 * dx;
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const float dx4 = dx3 * dx;
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const float cosdx =
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1.0f - lookup_table_.TERM2 * dx2 + lookup_table_.TERM4 * dx4;
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const float sindx = dx - lookup_table_.TERM3 * dx3;
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c[i] = cosv * cosdx - sinv * sindx;
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}
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}
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lookup_table<NR_SAMPLES> lookup_table_;
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};
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template <std::size_t NR_SAMPLES> struct sinf_dispatcher {
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constexpr sinf_dispatcher() : lookup_table_(){};
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template <class Tag, class Arch>
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void operator()(Arch, const size_t n, const float *a, float *s, Tag) const {
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using b_type = xsimd::batch<float, Arch>;
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using m_type = xsimd::batch<int32_t, Arch>;
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constexpr uint_fast32_t VL = b_type::size;
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const uint_fast32_t VS = n - n % VL;
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const uint_fast32_t Q_PI = NR_SAMPLES / 4U;
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const b_type scale = b_type::broadcast(lookup_table_.SCALE);
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const b_type pi_frac = b_type::broadcast(lookup_table_.PI_FRAC);
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const m_type mask = m_type::broadcast(lookup_table_.MASK);
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const b_type term1 = b_type::broadcast(lookup_table_.TERM1); // 1
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const b_type term2 = b_type::broadcast(lookup_table_.TERM2); // 1/2!
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const b_type term3 = b_type::broadcast(lookup_table_.TERM3); // 1/3!
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const b_type term4 = b_type::broadcast(lookup_table_.TERM4); // 1/4!
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const m_type quarter_pi = m_type::broadcast(Q_PI);
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uint_fast32_t i;
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for (i = 0; i < VS; i += VL) {
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const b_type vx = b_type::load(a + i, Tag());
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const b_type scaled = xsimd::mul(vx, scale);
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m_type idx = xsimd::to_int(scaled);
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b_type f_idx = xsimd::to_float(idx);
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const b_type dx = xsimd::sub(vx, xsimd::mul(f_idx, pi_frac));
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const b_type dx2 = xsimd::mul(dx, dx);
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const b_type dx3 = xsimd::mul(dx2, dx);
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const b_type dx4 = xsimd::mul(dx2, dx);
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const b_type t2 = xsimd::mul(dx2, term2);
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const b_type t3 = xsimd::mul(dx3, term3);
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const b_type t4 = xsimd::mul(dx4, term4);
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const b_type cosdx = xsimd::add(xsimd::sub(term1, t2), t4);
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const b_type sindx = xsimd::sub(dx, t3);
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idx = xsimd::bitwise_and(idx, mask);
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b_type sinv = b_type::gather(lookup_table_.sin_values.data(), idx);
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const b_type cosv = b_type::gather(lookup_table_.cos_values.data(), idx);
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sinv = xsimd::add(xsimd::mul(cosv, sindx), xsimd::mul(sinv, cosdx));
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sinv.store(s + i, Tag());
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}
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for (; i < n; i++) {
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std::size_t idx = static_cast<std::size_t>(a[i] * lookup_table_.SCALE);
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std::size_t masked = idx & lookup_table_.MASK;
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const float cosv = lookup_table_.cos_values[masked];
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const float sinv = lookup_table_.sin_values[masked];
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const float dx = a[i] - idx * lookup_table_.PI_FRAC;
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const float dx2 = dx * dx;
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const float dx3 = dx2 * dx;
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const float dx4 = dx3 * dx;
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const float cosdx =
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1.0f - lookup_table_.TERM2 * dx2 + lookup_table_.TERM4 * dx4;
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const float sindx = dx - lookup_table_.TERM3 * dx3;
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s[i] = sinv * cosdx + cosv * sindx;
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}
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}
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lookup_table<NR_SAMPLES> lookup_table_;
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};
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template <std::size_t NR_SAMPLES> struct sin_cosf_dispatcher {
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template <class Tag, class Arch>
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void operator()(Arch, const size_t n, const float *a, float *s, float *c,
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Tag) const {
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using b_type = xsimd::batch<float, Arch>;
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using m_type = xsimd::batch<int32_t, Arch>;
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constexpr uint_fast32_t VL = b_type::size;
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const uint_fast32_t VS = n - n % VL;
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const uint_fast32_t Q_PI = NR_SAMPLES / 4U;
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const b_type scale = b_type::broadcast(lookup_table_.SCALE);
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const m_type mask = m_type::broadcast(lookup_table_.MASK);
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const b_type pi_frac = b_type::broadcast(lookup_table_.PI_FRAC);
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const b_type term1 = b_type::broadcast(lookup_table_.TERM1); // 1
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const b_type term2 = b_type::broadcast(lookup_table_.TERM2); // 1/2!
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const b_type term3 = b_type::broadcast(lookup_table_.TERM3); // 1/3!
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const b_type term4 = b_type::broadcast(lookup_table_.TERM4); // 1/4!
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const m_type quarter_pi = m_type::broadcast(Q_PI);
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uint_fast32_t i;
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for (i = 0; i < VS; i += VL) {
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const b_type vx = b_type::load(a + i, Tag());
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const b_type scaled = xsimd::mul(vx, scale);
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m_type idx = xsimd::to_int(scaled);
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b_type f_idx = xsimd::to_float(idx);
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const b_type dx = xsimd::sub(vx, xsimd::mul(f_idx, pi_frac));
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const b_type dx2 = xsimd::mul(dx, dx);
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const b_type dx3 = xsimd::mul(dx2, dx);
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const b_type dx4 = xsimd::mul(dx2, dx);
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const b_type t2 = xsimd::mul(dx2, term2);
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const b_type t3 = xsimd::mul(dx3, term3);
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const b_type t4 = xsimd::mul(dx4, term4);
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idx = xsimd::bitwise_and(idx, mask);
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b_type sinv = b_type::gather(lookup_table_.sin_values.data(), idx);
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b_type cosv = b_type::gather(lookup_table_.cos_values.data(), idx);
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const b_type cosdx = xsimd::add(xsimd::sub(term1, t2), t4);
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const b_type sindx = xsimd::sub(dx, t3);
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sinv = xsimd::add(xsimd::mul(cosv, sindx), xsimd::mul(sinv, cosdx));
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cosv = xsimd::sub(xsimd::mul(cosv, cosdx), xsimd::mul(sinv, sindx));
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sinv.store(s + i, Tag());
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cosv.store(c + i, Tag());
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}
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for (; i < n; i++) {
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std::size_t idx = static_cast<std::size_t>(a[i] * lookup_table_.SCALE);
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std::size_t masked = idx & lookup_table_.MASK;
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const float cosv = lookup_table_.cos_values[masked];
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const float sinv = lookup_table_.sin_values[masked];
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const float dx = a[i] - idx * lookup_table_.PI_FRAC;
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const float dx2 = dx * dx;
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const float dx3 = dx2 * dx;
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const float dx4 = dx3 * dx;
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const float cosdx =
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1.0f - lookup_table_.TERM2 * dx2 + lookup_table_.TERM4 * dx4;
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const float sindx = dx - lookup_table_.TERM3 * dx3;
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s[i] = sinv * cosdx + cosv * sindx;
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c[i] = cosv * cosdx - sinv * sindx;
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}
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}
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lookup_table<NR_SAMPLES> lookup_table_;
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};
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template <std::size_t NR_SAMPLES> struct LookupXSIMDBackend<NR_SAMPLES>::Impl {
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cosf_dispatcher<NR_SAMPLES> cosf_dispatcher_;
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sinf_dispatcher<NR_SAMPLES> sinf_dispatcher_;
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sin_cosf_dispatcher<NR_SAMPLES> sin_cosf_dispatcher_;
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void init() {}
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void compute_sincosf(std::size_t n, const float *x, float *s,
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float *c) const {
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xsimd::dispatch(sin_cosf_dispatcher_)(n, x, s, c, xsimd::unaligned_mode());
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}
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void compute_sinf(std::size_t n, const float *x, float *s) const {
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xsimd::dispatch(sinf_dispatcher_)(n, x, s, xsimd::unaligned_mode());
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}
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void compute_cosf(std::size_t n, const float *x, float *c) const {
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xsimd::dispatch(cosf_dispatcher_)(n, x, c, xsimd::unaligned_mode());
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}
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};
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template <std::size_t NR_SAMPLES>
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LookupXSIMDBackend<NR_SAMPLES>::LookupXSIMDBackend()
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: impl(std::make_unique<Impl>()) {}
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template <std::size_t NR_SAMPLES>
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LookupXSIMDBackend<NR_SAMPLES>::~LookupXSIMDBackend() = default;
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template <std::size_t NR_SAMPLES>
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void LookupXSIMDBackend<NR_SAMPLES>::init(size_t) {
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impl->init();
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}
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template <std::size_t NR_SAMPLES>
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void LookupXSIMDBackend<NR_SAMPLES>::compute_sinf(const std::size_t n,
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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 <std::size_t NR_SAMPLES>
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void LookupXSIMDBackend<NR_SAMPLES>::compute_cosf(const std::size_t n,
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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 <std::size_t NR_SAMPLES>
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void LookupXSIMDBackend<NR_SAMPLES>::compute_sincosf(const std::size_t n,
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const float *x, float *s,
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float *c) const {
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impl->compute_sincosf(n, x, s, c);
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}
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// Explicit instantiations
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template class LookupXSIMDBackend<16384>;
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template class LookupXSIMDBackend<32768>;
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