void convo2d()
{
/*ID FFT Row wise*/
for (i = 0; i<MAXN; i++)
{
fft1d(data1[i], MAXN, -1);
fft1d(data2[i], MAXN, -1);
}
/*Transpose*/
for (i = 0; i < MAXN; i++)
{
for (j = i; j < MAXN; j++)
{
C_SWAP(data1[i][j], data1[j][i]);
C_SWAP(data2[i][j], data2[j][i]);
}
}
/*1D FFT Row wise (Transposed Column)*/
for (i = 0; i<MAXN; i++)
{
fft1d(data1[i], MAXN, -1);
fft1d(data2[i], MAXN, -1);
}
/*Point Multiplication*/
for (i = 0; i < MAXN; i++)
{
for (j = 0; j < MAXN; j++)
{
data3[i][j].r = data1[i][j].r * data2[i][j].r - data1[i][j].i * data2[i][j].i;
data3[i][j].i = data1[i][j].r * data2[i][j].i + data1[i][j].i * data2[i][j].r;
}
}
/*1D IFFT Row wise*/
for (i = 0; i<MAXN; i++)
{
fft1d(data3[i], MAXN, 1);
}
/*Transpose*/
for (j = 0; j < MAXN; j++)
{
for (i = j; i < MAXN; i++)
{
C_SWAP(data3[i][j], data3[j][i]);
}
}
/*1D IFFT Row wise (Transposed Column)*/
for (i = 0; i<MAXN; i++)
{
fft1d(data3[i], MAXN, 1);
}
}
void c_vector_swap(c_pvector thiz, c_pvector V)
{
c_vector tmp;
C_SWAP(*thiz, *V, tmp);
}
void c_fft1d(complex *r, int n, int isign)
{
int m,i,i1,j,k,i2,l,l1,l2;
float c1,c2,z;
complex t, u;
if (isign == 0) return;
/* Do the bit reversal */
i2 = n >> 1;
j = 0;
for (i=0;i<n-1;i++) {
if (i < j)
C_SWAP(r[i], r[j]);
k = i2;
while (k <= j) {
j -= k;
k >>= 1;
}
j += k;
}
/* m = (int) log2((double)n); */
for (i=n,m=0; i>1; m++,i/=2);
/* Compute the FFT */
c1 = -1.0;
c2 = 0.0;
l2 = 1;
for (l=0;l<m;l++) {
l1 = l2;
l2 <<= 1;
u.r = 1.0;
u.i = 0.0;
for (j=0;j<l1;j++) {
for (i=j;i<n;i+=l2) {
i1 = i + l1;
/* t = u * r[i1] */
t.r = u.r * r[i1].r - u.i * r[i1].i;
t.i = u.r * r[i1].i + u.i * r[i1].r;
/* r[i1] = r[i] - t */
r[i1].r = r[i].r - t.r;
r[i1].i = r[i].i - t.i;
/* r[i] = r[i] + t */
r[i].r += t.r;
r[i].i += t.i;
}
z = u.r * c1 - u.i * c2;
u.i = u.r * c2 + u.i * c1;
u.r = z;
}
c2 = sqrt((1.0 - c1) / 2.0);
if (isign == -1) /* FWD FFT */
c2 = -c2;
c1 = sqrt((1.0 + c1) / 2.0);
}
/* Scaling for inverse transform */
if (isign == 1) { /* IFFT*/
for (i=0;i<n;i++) {
r[i].r /= n;
r[i].i /= n;
}
}
}
