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main.cpp
219 lines (217 loc) · 6.55 KB
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main.cpp
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#include <algorithm>
#include <array>
#include <cmath>
#include <complex>
#include <iomanip>
#include <iostream>
#include <sys/time.h>
enum Constants { M_MAG_N = 32 };
std::array<std::complex<float>, M_MAG_N> m_fft_in = {
{(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f)}};
std::array<std::complex<float>, M_MAG_N> m_fft_out = {
{(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f)}};
std::array<std::complex<float>, M_MAG_N> m_fft_out2 = {
{(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f)}};
std::array<float, M_MAG_N> m_fft_out_mag = {
{(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f), (0.0e+0f),
(0.0e+0f), (0.0e+0f)}};
static inline uint64_t current_time() {
{
struct timeval tv;
gettimeofday(&tv, nullptr);
return ((tv.tv_sec * 1000000) + tv.tv_usec);
}
}
template <std::size_t N>
void ft(const std::array<std::complex<float>, N> &in,
std::array<std::complex<float>, N> &out) {
for (unsigned int k = 0; (k < N); k += 1) {
out[k] = 0;
}
for (unsigned int k = 0; (k < N); k += 1) {
for (unsigned int n = 0; (n < N); n += 1) {
out[k] +=
(std::exp(std::complex<float>((0.0e+0f), ((M_PI * -2 * k * n) / N))) *
in[n]);
}
}
}
template <std::size_t N>
void bit_reverse_copy(const std::array<std::complex<float>, N> &in,
std::array<std::complex<float>, N> &out) {
out[0] = in[0];
out[16] = in[1];
out[8] = in[2];
out[24] = in[3];
out[4] = in[4];
out[20] = in[5];
out[12] = in[6];
out[28] = in[7];
out[2] = in[8];
out[18] = in[9];
out[10] = in[10];
out[26] = in[11];
out[6] = in[12];
out[22] = in[13];
out[14] = in[14];
out[30] = in[15];
out[1] = in[16];
out[17] = in[17];
out[9] = in[18];
out[25] = in[19];
out[5] = in[20];
out[21] = in[21];
out[13] = in[22];
out[29] = in[23];
out[3] = in[24];
out[19] = in[25];
out[11] = in[26];
out[27] = in[27];
out[7] = in[28];
out[23] = in[29];
out[15] = in[30];
out[31] = in[31];
}
template <std::size_t N>
void fft(const std::array<std::complex<float>, N> &in,
std::array<std::complex<float>, N> &out) {
bit_reverse_copy(in, out);
{
const auto w_m = std::complex<float>((-1.e+0f), (-1.2246469e-16f));
for (auto k = 0; (k < N); k += 2) {
{
std::complex<float> w(1);
for (unsigned int j = 0; (j < 1); j += 1) {
{
auto t((w * out[(k + j + 1)]));
auto u(out[(k + j)]);
out[(k + j)] = (u + t);
out[(k + j + 1)] = (u - t);
w = (w * w_m);
}
}
}
}
}
{
const auto w_m = std::complex<float>((6.123234e-17f), (-1.e+0f));
for (auto k = 0; (k < N); k += 4) {
{
std::complex<float> w(1);
for (unsigned int j = 0; (j < 2); j += 1) {
{
auto t((w * out[(k + j + 2)]));
auto u(out[(k + j)]);
out[(k + j)] = (u + t);
out[(k + j + 2)] = (u - t);
w = (w * w_m);
}
}
}
}
}
{
const auto w_m = std::complex<float>((7.0710677e-1f), (-7.0710677e-1f));
for (auto k = 0; (k < N); k += 8) {
{
std::complex<float> w(1);
for (unsigned int j = 0; (j < 4); j += 1) {
{
auto t((w * out[(k + j + 4)]));
auto u(out[(k + j)]);
out[(k + j)] = (u + t);
out[(k + j + 4)] = (u - t);
w = (w * w_m);
}
}
}
}
}
{
const auto w_m = std::complex<float>((9.238795e-1f), (-3.8268343e-1f));
for (auto k = 0; (k < N); k += 16) {
{
std::complex<float> w(1);
for (unsigned int j = 0; (j < 8); j += 1) {
{
auto t((w * out[(k + j + 8)]));
auto u(out[(k + j)]);
out[(k + j)] = (u + t);
out[(k + j + 8)] = (u - t);
w = (w * w_m);
}
}
}
}
}
{
const auto w_m = std::complex<float>((9.8078525e-1f), (-1.9509032e-1f));
for (auto k = 0; (k < N); k += 32) {
{
std::complex<float> w(1);
for (unsigned int j = 0; (j < 16); j += 1) {
{
auto t((w * out[(k + j + 16)]));
auto u(out[(k + j)]);
out[(k + j)] = (u + t);
out[(k + j + 16)] = (u - t);
w = (w * w_m);
}
}
}
}
}
}
int main() {
for (unsigned int i = 0; (i < M_MAG_N); i += 1) {
m_fft_in[i] = (0.0e+0f);
m_fft_out[i] = (0.0e+0f);
m_fft_out_mag[i] = (0.0e+0f);
}
m_fft_in[1] = (1.e+0f);
{
auto start(current_time());
for (unsigned int i = 0; (i < 10); i += 1) {
ft(m_fft_in, m_fft_out);
}
(std::cout << "time: " << (((1.e+0f) / (1.e+3f)) * (current_time() - start))
<< " ms" << std::endl);
}
for (unsigned int i = 0; (i < M_MAG_N); i += 1) {
m_fft_in[i] = (0.0e+0f);
m_fft_out2[i] = (0.0e+0f);
m_fft_out_mag[i] = (0.0e+0f);
}
m_fft_in[1] = (1.e+0f);
{
auto start(current_time());
for (unsigned int i = 0; (i < 10); i += 1) {
fft(m_fft_in, m_fft_out2);
}
(std::cout << "time: " << (((1.e+0f) / (1.e+3f)) * (current_time() - start))
<< " ms" << std::endl);
}
for (unsigned int i = 0; (i < M_MAG_N); i += 1) {
(std::cout << std::setw(6) << i << std::setw(30) << m_fft_out[i]
<< std::setw(30) << m_fft_out2[i] << std::endl);
}
}