C# implementation of PeakDet algorithm from: http://www.billauer.co.il/peakdet.html

PeakDet.cs

public static IList<(int pos, double val)> PeakDet(this IList<double> vector, double triggerDelta)
{
    double mn = Double.PositiveInfinity;
    double mx = Double.NegativeInfinity;
    int mnpos = 0;
    int mxpos = 0;
    bool lookformax = true;

    var maxtab_tmp = new List<(int pos, double val)>();
    //var mintab_tmp = new List<(int pos, double val)>();

    for (int i = 0; i < vector.Count; i++)
    {
        double a = vector[i];
        if (a > mx)
        {
            mx = a;
            mxpos = i;
        }
        if (a < mn)
        {
            mn = a;
            mnpos = i;
        }
        if (lookformax)
        {
            if (a < mx - triggerDelta)
            {
                maxtab_tmp.Add((mxpos, mx));
                mn = a;
                mnpos = i;
                lookformax = false;
            }
        }
        else
        {
            if (a > mn + triggerDelta)
            {
                //mintab_tmp.Add((mnpos, ns));
                mx = a;
                mxpos = i;
                lookformax = true;
            }
        }
    }

    return maxtab_tmp;
}