用C语言对瞬时值进行傅里叶变换的程序怎么写

以下是用C语言对瞬时值进行傅里叶变换的程序：

#include <stdio.h>
#include <math.h>

#define PI 3.14159265358979323846

void fourier(double xr[], double xi[], int n, int inverse)
{
int i, j, k, m, steps;
double tmp, wpr, wpi, wr, wi, theta;

steps = log(n) / log(2); //计算需要计算的轮数

for (i = 0; i < n; i++) {
j = 0;
for (k = 0; k < steps; k++) //反转二进制码
j |= ((i >> k) & 1) << (steps - 1 - k);
if (j > i) {
tmp = xr[i];
xr[i] = xr[j];
xr[j] = tmp;
tmp = xi[i];
xi[i] = xi[j];
xi[j] = tmp;
}
}

for (i = 0; i < steps; i++) {
m = 1 << i;
wpr = cos(PI / m);
if (inverse)
wpi = sin(PI / m);
else
wpi = -sin(PI / m);
wr = 1.0;
wi = 0.0;
for (j = 0; j < m; j++) {
for (k = j; k < n; k += 2 * m) {
tmp = wr * xr[k + m] - wi * xi[k + m];
xi[k + m] = wr * xi[k + m] + wi * xr[k + m];
xr[k + m] = tmp;
}
theta = wpr * wr - wpi * wi;
wi = wpr * wi + wpi * wr;
wr = theta;
}
}
if (inverse) {
for (i = 0; i < n; i++) {
xr[i] /= n;
xi[i] /= n;
}
}
}

int main()
{
double xr[] = {1, 2, 3, 4, 5, 6, 7, 8};
double xi[] = {0, 0, 0, 0, 0, 0, 0, 0};
int n = 8;
int inverse = 0;
int i;

printf("实部 虚部\n");
fourier(xr, xi, n, inverse);
for (i = 0; i < n; i++) {
printf("%lf %lf i\n", xr[i], xi[i]);
}
return 0;
}

注意：这是一个简单的傅里叶变换的实例代码，并不考虑实用性和效率问题。在实际应用中，可能需要更高效的算法和实现才能满足要求。