public void Add(int index, double v)
{
if (index < _stat.Length)
{
RunningStatValue.Add(ref _stat[index], ref _n[index], v);
}
}
public static void Add(ref RunningStatValue stat, ref double n, double x)
{
var np1 = n + 1;
var oldM = stat._oldM;
var oldS = stat._oldS;
var newM = oldM + (x - oldM) / np1;
var newS = oldS + (x - oldM) * (x - newM);
stat._oldM = newM;
stat._oldS = newS;
stat._newM = newM;
stat._newS = newS;
n = np1;
}