public FunctionTableItem[] DFTransform(FunctionTableItem[] original, int direction)
{
FunctionTableItem[] image = new FunctionTableItem[original.Length];
Complex tmp;
Complex power;
for (int i = 0; i < original.Length; i++)
{
image[i] = new FunctionTableItem();
}
ActionCount = 0;
for (int n = 0; n < original.Length; n++)
{
tmp = new Complex(0, 0);
for (int k = 0; k < original.Length; k++)
{
ActionCount++;
power = direction * 2 * Complex.ImaginaryOne * Math.PI * n * k / original.Length;
tmp += original[k].Value * Complex.Exp(power);
}
image[n].Value = tmp / Math.Sqrt((double)original.Length);
}
return(image);
}
public FunctionTableItem[] Transform(FunctionTableItem[] original)
{
FunctionTableItem[] res = DFTransform(original, -1);
for(int i = 0 ; i < res.Length ; i++)
{
res[i].Arg = i;
}
return res;
}
public FunctionTableItem[] Inverse(FunctionTableItem[] image)
{
FunctionTableItem[] res = DFTransform(image, 1);
for(int i = 0 ; i < res.Length ; i++)
{
res[i].Arg = i;
}
return res;
}
public int Butterfly(FunctionTableItem a, FunctionTableItem b, int n, int m, int direction)
{
Complex W = Complex.Exp(direction * Complex.ImaginaryOne * 2 * Math.PI * m / n);
Complex tempa = a.Value + b.Value;
Complex tempb = (a.Value - b.Value) * W;
a.Value = tempa;
b.Value = tempb;
this.ActionCount++;
return 0;
}
public int Butterfly(FunctionTableItem a, FunctionTableItem b, int n, int m, int direction)
{
Complex W = Complex.Exp(direction * Complex.ImaginaryOne * 2 * Math.PI * m / n);
Complex tempa = a.Value + b.Value;
Complex tempb = (a.Value - b.Value) * W;
a.Value = tempa;
b.Value = tempb;
this.ActionCount++;
return(0);
}
public FunctionTableItem[] Transform(FunctionTableItem[] original)
{
FunctionTableItem[] image;
image = FTTransform(original, -1);
image = Swap(image);
for (int i = 0; i < image.Length; i++)
{
image[i].Value /= Math.Sqrt((double) image.Length);
image[i].Arg = i;
}
return image;
}
public FunctionTableItem[] Inverse(FunctionTableItem[] image)
{
FunctionTableItem[] original;
original = FTTransform(image, 1);
original = Swap(original);
for (int i = 0; i < original.Length; i++)
{
original[i].Value /= Math.Sqrt((double) original.Length);
original[i].Arg = i;
}
return original;
}
public FunctionTableItem[] FTTransform(FunctionTableItem[] original, int direction)
{
int dist;
if (original.Length > 1)
{
dist = original.Length / 2;
for (int i = 0; i < dist; i++)
{
Butterfly(original[i], original[i + dist], original.Length, i, direction);
}
FTTransform(original.Take(dist).ToArray(), direction).CopyTo(original, 0);
FTTransform(original.Skip(dist).ToArray(), direction).CopyTo(original, dist);
/*for(int i = 0 ; i < dist ; i++)
{
original[2*i] = fe[i];
original[2*i + 1] = fo[i];
}*/
}
return original;
}
private FunctionTableItem[] Swap(FunctionTableItem[] toSwap)
{
FunctionTableItem[] swapped = new FunctionTableItem[toSwap.Length];
FunctionTableItem tmp;
int[] map;
map = GetBinaryInvertedList(toSwap.Length);
for (int i = 0; i < toSwap.Length / 2; i++)
{
tmp = toSwap[i];
toSwap[i] = toSwap[map[i]];
toSwap[map[i]] = tmp;
toSwap[i].Arg = i;
}
for (int i = 0; i < toSwap.Length; i++)
{
toSwap[i].Arg = i;
}
return(toSwap);
}
public FunctionTableItem[] DFTransform(FunctionTableItem[] original, int direction)
{
FunctionTableItem[] image = new FunctionTableItem[original.Length];
Complex tmp;
Complex power;
for (int i = 0; i < original.Length; i++ )
image[i] = new FunctionTableItem();
ActionCount = 0;
for (int n = 0; n < original.Length; n++)
{
tmp = new Complex(0,0);
for (int k = 0; k < original.Length; k++)
{
ActionCount++;
power = direction * 2 * Complex.ImaginaryOne * Math.PI * n * k / original.Length;
tmp += original[k].Value*Complex.Exp(power);
}
image[n].Value = tmp / Math.Sqrt((double)original.Length);
}
return image;
}
private FunctionTableItem[] Swap(FunctionTableItem[] toSwap)
{
FunctionTableItem[] swapped = new FunctionTableItem[toSwap.Length];
FunctionTableItem tmp;
int[] map;
map = GetBinaryInvertedList(toSwap.Length);
for(int i = 0 ; i < toSwap.Length/2 ; i++)
{
tmp = toSwap[i];
toSwap[i] = toSwap[map[i]];
toSwap[map[i]] = tmp;
toSwap[i].Arg = i;
}
for (int i = 0; i < toSwap.Length; i++)
toSwap[i].Arg = i;
return toSwap;
}
