public double[] BackwardTransform(Complex[] mas)
{
mas = GetArrayInRightOrder(FFT(mas, false));
var results = new double[mas.Count()];
for (int i = 0; i < results.Length; i++ )
{
results[i] = mas[i].Real/results.Length;
}
return results;
}
private Complex[] FFT(Complex[] mas, bool isForward)
{
int N = mas.Count();
Complex Wn = CalculateWn(isForward, N);
int k = mas.Length;
var y = new Complex[k];
var W = new Complex(1, 0);
for (int j = 0; j < k / 2; j++)
{
y[j] = mas[j] + mas[j + k / 2];
y[j + k / 2] = W * (mas[j] - mas[j + k / 2]);
W = W * Wn;
}
var mas11 = new Complex[N / 2];
var mas22 = new Complex[N / 2];
for (int i = 0; i < N / 2; i++ )
{
mas11[i] = y[i];
mas22[i] = y[i + N / 2];
}
if (N > 2)
{
mas11 = FFT(mas11, isForward);
mas22 = FFT(mas22, isForward);
}
var masRes = new Complex[N];
for (int i = 0; i < N / 2; i ++ )
{
masRes[i] = mas11[i];
masRes[i + N / 2] = mas22[i];
}
return masRes;
}
private Complex[] ButterflyMethod(Complex[] a, bool isForward)
{
Complex Wn = CalculateWn(isForward, a.Count());
int k = a.Length;
var y = new Complex[k];
var W = new Complex(1, 0);
for(int j = 0; j < k / 2; j++)
{
y[j] = a[j] + a[j + k / 2];
y[j + k / 2] = W * (a[j] - a[j + k / 2]);
W = W * Wn;
}
return y;
}
public IIR_Spectrum_Objective(int Filter_Order, Complex[] BasisSpectrum, int samplingFrequency)
{
//Find all local maxima (within 10 points)
List<int> maxima = new List<int>();
freq = new double[BasisSpectrum.Length];
for (int i = 10; i < BasisSpectrum.Length-10; i++)
{
bool max = true;
for (int s = -10; s < 10; s++)
{
if (BasisSpectrum[i].Real < BasisSpectrum[i + s].Real)
{
max = false;
continue;
}
}
if (max) maxima.Add(i);
}
fs = samplingFrequency;
for (int i = 0; i < freq.Length; i++) freq[i] = (double)(i * samplingFrequency) / freq.Length;
pole_phase = new double[maxima.Count];
for (int i = 0; i < maxima.Count; i++) pole_phase[i] = 2 * Math.PI * maxima[i] / BasisSpectrum.Count();
if (Filter_Order < maxima.Count * 2) Filter_Order = maxima.Count * 2;
pzct = Filter_Order;
pno_conj = (int)Math.Floor((double)pzct / 2);
pno_conj_phase = (int)Math.Floor((double)pzct / 2 - maxima.Count());
pno_real = pzct % 2;
zno_real = pzct;
Spectrum = BasisSpectrum;
n = BasisSpectrum.Length;
fs = samplingFrequency;
sampled = new int[24];
sel_Spectrum = new Complex[24];
sel_freq = new double[24];
abs = new Complex[24];
for (int i = 0; i < 24; i++)
{
double f = 24.803 * Math.Pow(2, (double)i/3);
sampled[i] = (int)(f * 2 * BasisSpectrum.Length / samplingFrequency);
sel_Spectrum[i] = Spectrum[sampled[i]];
abs[i] = AbsorptionModels.Operations.Absorption_Coef(sel_Spectrum[i]);
sel_freq[i] = freq[sampled[i]];
}
}