/// <summary>
/// Gets the peak that fits the point at a given index with a Lorentzian fit.
/// </summary>
/// <param name="index">index of the point in the m/z vectors which is the apex of the peak.</param>
/// <param name="mzs">List of raw data of m\zs.</param>
/// <param name="intensities">List of raw data of intensities.</param>
/// <param name="fwhm"></param>
/// <returns>returns the m/z of the peak.</returns>
private double LorentzianFit(List <double> mzs, List <double> intensities, int index, double fwhm)
{
var a = intensities[index];
var vo = mzs[index];
var e = Math.Abs((vo - mzs[index + 1]) / 100);
if (index < 1)
{
return(mzs[index]);
}
if (index == mzs.Count)
{
return(mzs[index]);
}
var lstart = PeakIndex.GetNearest(mzs, vo + fwhm, index) + 1;
var lstop = PeakIndex.GetNearest(mzs, vo - fwhm, index) - 1;
var currentE = LorentzianLS(mzs, intensities, a, fwhm, vo, lstart, lstop);
for (var i = 0; i < 50; i++)
{
var lastE = currentE;
vo = vo + e;
currentE = LorentzianLS(mzs, intensities, a, fwhm, vo, lstart, lstop);
if (currentE > lastE)
{
break;
}
}
vo = vo - e;
currentE = LorentzianLS(mzs, intensities, a, fwhm, vo, lstart, lstop);
for (var i = 0; i < 50; i++)
{
var lastE = currentE;
vo = vo - e;
currentE = LorentzianLS(mzs, intensities, a, fwhm, vo, lstart, lstop);
if (currentE > lastE)
{
break;
}
}
vo = vo + e;
return(vo);
}
/// <summary>
/// Gets the signal to noise for a point.
/// </summary>
/// <param name="mzList">is List of m/z values.</param>
/// <param name="intensityList">is List of intensity values.</param>
/// <param name="peak">is the m/z value at which we want to find the signal to noise ratio.</param>
/// <returns>returns the signal to noise value of the peak.</returns>
public double GetSignalToNoise(List <double> mzList, List <double> intensityList, double peak)
{
var index = PeakIndex.GetNearest(mzList, peak, 0);
return(PeakStatistician.FindSignalToNoise(intensityList[index], intensityList, index));
}
/// <summary>
/// Gets the FWHM for a point.
/// </summary>
/// <param name="mzList">is List of m/z values.</param>
/// <param name="intensityList">is List of intensity values.</param>
/// <param name="peak">is the m/z value at which we want to find FWHM.</param>
/// <returns>returns the m/z value of the peak.</returns>
public double GetFWHM(List <double> mzList, List <double> intensityList, double peak)
{
var index = PeakIndex.GetNearest(mzList, peak, 0);
return(PeakStatistician.FindFwhm(mzList, intensityList, index));
}