public static unsafe DwtOutput Forward(double[] input, Wavelet wavelet, Int32 level)
{
Int32 Len = wavelet.DecompositionLow.Length;
Int32 CircleInd;
double[] output = new Double[input.Length];
Double[] Buff = new Double[input.Length];
Buffer.BlockCopy(input, 0, output, 0, input.Length * 8);
Double BufScal = 0;
Double BufDet = 0;
Double *DecLow = stackalloc Double[Len];
Double *DecHigh = stackalloc Double[Len];
for (int i = 0; i < Len; i++)
{
DecLow[i] = wavelet.DecompositionLow[i];
DecHigh[i] = wavelet.DecompositionHigh[i];
}
fixed(Double *pout = output, pbuf = Buff)
{
for (int lvl = 0; lvl < level; lvl++)
{
Int32 Bound = input.Length >> lvl;
Int32 StartIndex = -((Len >> 1) - 1);
Buffer.BlockCopy(output, 0, Buff, 0, Bound * 8);
for (int i = 0; i < Bound >> 1; i++)
{
for (int j = StartIndex, k = 0; k < Len; j++, k++)
{
if ((StartIndex < 0) || j >= Bound)
{
CircleInd = ((j % Bound) + Bound) % Bound;
}
else
{
CircleInd = j;
}
BufScal += DecLow[k] * pout[CircleInd];
BufDet += DecHigh[k] * pout[CircleInd];
}
StartIndex += 2;
pbuf[i] = BufScal;
pbuf[i + (Bound >> 1)] = BufDet;
BufScal = 0;
BufDet = 0;
}
Buffer.BlockCopy(Buff, 0, output, 0, Bound * 8);
}
}
DwtOutput res = new DwtOutput(output, level, wavelet);
return(res);
}
public DwtOutput(double[] output, int level, Wavelet wavelet)
{
Level = level;
Wavelet = wavelet;
ApproximationCoefficients = new double[output.Length / (level + 1)];
Array.Copy(output, ApproximationCoefficients, ApproximationCoefficients.Length);
DetailCoefficients = new double[output.Length - ApproximationCoefficients.Length];
Array.Copy(output, ApproximationCoefficients.Length, DetailCoefficients, 0, output.Length - ApproximationCoefficients.Length);
FullVector = output;
}