Ehlers ZeroLag EMA

#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Aqua
#property indicator_color2 Red
#property indicator_width2 2

extern int MAPeriod    = 20;
extern int MAGainLimit = 50;

double EMABuffer[];
double ECBuffer[];

double gdAlpha = 0;

int init()
{
    SetIndexStyle(0, DRAW_LINE);
    SetIndexBuffer(0, EMABuffer);
    SetIndexStyle(1, DRAW_LINE);
    SetIndexBuffer(1, ECBuffer);
    IndicatorShortName("ZeroLagMA("+MAPeriod+")");
    SetIndexLabel(0, "EMA");
    SetIndexLabel(1, "EC");

    gdAlpha = 2.0 / (MAPeriod + 1.0);
    return(0);
}

int start()
{
    int    i, j, iCounted, iLimit;
    double dGain, dBestGain, dError, dLeastError, dEC;
    
    iCounted = IndicatorCounted();
    if(iCounted > 0) 
      iCounted--;
    iLimit = Bars - iCounted;
    for(i = iLimit-1; i >= 0; i--)
    {
        EMABuffer[i] = gdAlpha * Close[i] + (1 - gdAlpha) * EMABuffer[i+1];
        dLeastError = 1000000;
        for(j = -MAGainLimit; j <= MAGainLimit; j++)
        {
            dGain = j / 10;
            dEC = gdAlpha * (EMABuffer[i] + dGain*(Close[i] - ECBuffer[i+1])) + (1 - gdAlpha) * ECBuffer[i+1];
            dError = Close[i] - dEC;
            if(MathAbs(dError) < dLeastError)
            {
                dLeastError = MathAbs(dError);
                dBestGain = dGain;
            }
        }
        ECBuffer[i] = gdAlpha * (EMABuffer[i] + dBestGain * (Close[i] - ECBuffer[i+1])) + (1 - gdAlpha) * ECBuffer[i+1];
    }
    return(0);
}