Hull moving average
HMA(expr, count) or HAvg(expr, count)
expr - data series formula
count - lookback period
Either HMA or HAvg can be used as the name of this function.
The Hull moving average is calculated using nested weighted moving averages (WMA).
HMA(expr, count) could be calculated as WMA((2 * WMA(expr, count/2) - WMA(expr, count)), SQR(count)).