public static void FFT1(Complex[] data, int exponent, FFTMode mode)
{
//count; if exponent = 12 -> c = 2^12 = 4096
int c = (int)Math.Pow(2, exponent);
//binary inversion
Inverse(data, c);
int j0, j1, j2 = 1;
float n0, n1, tr, ti, m;
float v0 = -1, v1 = 0;
//move to outer scope to optimize performance
int j, i;
for (int l = 0; l < exponent; l++)
{
n0 = 1;
n1 = 0;
j1 = j2;
j2 <<= 1; //j2 * 2
for (j = 0; j < j1; j++)
{
for (i = j; i < c; i += j2)
{
j0 = i + j1;
//--
tr = n0 * data[j0].Real - n1 * data[j0].Imaginary;
ti = n0 * data[j0].Imaginary + n1 * data[j0].Real;
//--
data[j0].Real = data[i].Real - tr;
data[j0].Imaginary = data[i].Imaginary - ti;
//add
data[i].Real += tr;
data[i].Imaginary += ti;
}
//calc coeff
m = v0 * n0 - v1 * n1;
n1 = v1 * n0 + v0 * n1;
n0 = m;
}
if (mode == FFTMode.Forward)
{
v1 = (float)Math.Sqrt((1f - v0) / 2f);
}
else
{
v1 = (float)-Math.Sqrt((1f - v0) / 2f);
}
v0 = (float)Math.Sqrt((1f + v0) / 2f);
}
if (mode == FFTMode.Forward)
{
Forward(data, c);
}
}
public static void FFT1(Complex[] data, int exponent, FFTMode mode)
{
//count; if exponent = 12 -> c = 2^12 = 4096
int c = (int)Math.Pow(2, exponent);
//binary inversion
Inverse(data, c);
int j0, j1, j2 = 1;
float n0, n1, tr, ti, m;
float v0 = -1, v1 = 0;
//move to outer scope to optimize performance
int j, i;
for (int l = 0; l < exponent; l++)
{
n0 = 1;
n1 = 0;
j1 = j2;
j2 <<= 1; //j2 * 2
for (j = 0; j < j1; j++)
{
for (i = j; i < c; i += j2)
{
j0 = i + j1;
//--
tr = n0 * data[j0].Real - n1 * data[j0].Imaginary;
ti = n0 * data[j0].Imaginary + n1 * data[j0].Real;
//--
data[j0].Real = data[i].Real - tr;
data[j0].Imaginary = data[i].Imaginary - ti;
//add
data[i].Real += tr;
data[i].Imaginary += ti;
}
//calc coeff
m = v0 * n0 - v1 * n1;
n1 = v1 * n0 + v0 * n1;
n0 = m;
}
if (mode == FFTMode.Forward)
{
v1 = (float)Math.Sqrt((1f - v0) / 2f);
}
else
{
v1 = (float)-Math.Sqrt((1f - v0) / 2f);
}
v0 = (float)Math.Sqrt((1f + v0) / 2f);
}
if (mode == FFTMode.Forward)
{
Forward(data, c);
}
}
