/****************************************************************************
* TrimFFT
* Trim FFT array prior to Lorentzian fitting based on user specifications
****************************************************************************/
public FFTData TrimFFT(FFTData fftData, LorentzSettings lorentzSettings)
{
FFTData fftTrimData = new FFTData();
int startIndex = Array.FindIndex(fftData.freq, x => x >= lorentzSettings.trimStartFreq);
int stopIndex = Array.FindIndex(fftData.freq, x => x >= lorentzSettings.trimStopFreq);
fftTrimData.fft = fftData.fft.ToList().Skip(startIndex + 1).Take(stopIndex - startIndex).ToArray();
fftTrimData.freq = fftData.freq.ToList().ToList().Skip(startIndex + 1).Take(stopIndex - startIndex).ToArray();
return(fftTrimData);
}
// LORENTZIAN FITTING //
/****************************************************************************
* GetLorentzParams
* Get lorentzian fitting parameters
****************************************************************************/
public void GetLorentzParams(FFTData fftData, LorentzSettings lorentzSettings, ref LorentzParams lorentzParams)
{
double[][] dataPoints = new double[][] { fftData.freq, fftData.fft };
LMA algorithm;
if (lorentzSettings.isYShiftLorentz)
{
LMAFunction lorentzShift = new LorenzianFunctionShift();
double[] startPoint = new double[4];
try
{
startPoint[0] = lorentzSettings.startPointLP.A;
}
catch (Exception)
{
startPoint[0] = 10;
}
try
{
startPoint[1] = lorentzSettings.startPointLP.f0;
}
catch (Exception)
{
startPoint[1] = 25;
}
try
{
startPoint[2] = lorentzSettings.startPointLP.gamma;
}
catch (Exception)
{
startPoint[2] = 1;
}
try
{
startPoint[3] = lorentzSettings.startPointLP.up;
}
catch (Exception)
{
startPoint[3] = 1;
}
algorithm = new LMA(lorentzShift, startPoint,
dataPoints, null, new GeneralMatrix(4, 4), 1d - 20, lorentzSettings.nIter);
algorithm.Fit();
lorentzParams.A = algorithm.Parameters[0];
lorentzParams.gamma = algorithm.Parameters[2];
lorentzParams.f0 = algorithm.Parameters[1];
lorentzParams.up = algorithm.Parameters[3];
}
else
{
LMAFunction lorentz = new LorenzianFunction();
double[] startPoint = new double[3];
try
{
startPoint[0] = lorentzSettings.startPointLP.A;
}
catch (Exception)
{
startPoint[0] = 10;
}
try
{
startPoint[1] = lorentzSettings.startPointLP.f0;
}
catch (Exception)
{
startPoint[1] = 25;
}
try
{
startPoint[2] = lorentzSettings.startPointLP.gamma;
}
catch (Exception)
{
startPoint[2] = 1;
}
algorithm = new LMA(lorentz, startPoint,
dataPoints, null, new GeneralMatrix(3, 3), 1d - 20, lorentzSettings.nIter);
algorithm.Fit();
lorentzParams.A = algorithm.Parameters[0];
lorentzParams.gamma = algorithm.Parameters[2];
lorentzParams.f0 = algorithm.Parameters[1];
lorentzParams.up = 0;
}
}
