/// <summary>Computes the inverse Discrete Fourier Transform of a float2 vector x whose length is a power of 4.
/// x = { Re[x0] Im[x0] Re[x1] Im[x1] ... Re[xn] Im[xn] }, n = power of 4 (Length = 2*pow(4,n))</summary>
public static CLCalc.Program.Variable iFFT4(CLCalc.Program.Variable CLx)
{
if (CLScale == null) CLScale = new CLCalc.Program.Variable(new float[1]);
//Trick: DFT-1 (x) = DFT(x*)*/N;
//Conjugate
float[] vx = new float[CLx.OriginalVarLength];
CLx.ReadFromDeviceTo(vx);
float[] scale = new float[] { 1 };
CLScale.WriteToDevice(scale);
kernelConjugate.Execute(new CLCalc.Program.Variable[] { CLx, CLScale }, CLx.OriginalVarLength >> 1);
CLx.ReadFromDeviceTo(vx);
CLy = FFT4(ref CLx);
scale[0] = 1 / (float)(CLx.OriginalVarLength >> 1);
CLScale.WriteToDevice(scale);
kernelConjugate.Execute(new CLCalc.Program.Variable[] { CLy, CLScale }, CLy.OriginalVarLength >> 1);
return CLy;
}