```
input n = 10;
def bar = BarNumber();
def nan = Double.NaN;
input Agg = AggregationPeriod.day;
input Length = 500;
input AverageType = AverageType.SIMPLE;
input ATRMulti = .75;
def h = high(period = Agg);
def l = low(period = Agg);
def c = close(period = Agg);
def PMhrs = RegularTradingStart (GetYYYYMMDD()) > GetTime();
def RMhrs = RegularTradingStart (GetYYYYMMDD()) < GetTime();
def PMStart = RMhrs[1] and PMhrs;
def PMclose = CompoundValue(1, if PMStart then h else if PMhrs then Max(h, PMclose[1]) else PMclose[1], 0);
def PMHigh = CompoundValue(1, if PMStart then h else if PMhrs then Max(h, PMHigh[1]) else PMHigh[1], 0);
def PMLow = CompoundValue(1, if PMStart then l else if PMhrs then Min(l, PMLow[1]) else PMLow[1], 0);
def highBar = if PMhrs and h == PMHigh then bar else nan;
def lowBar = if PMhrs and l == PMLow then bar else nan;
def PMHighBar = if bar == HighestAll(highBar) then PMHigh else PMHighBar[1];
def PMLowBar = if bar == HighestAll(lowBar) then PMLow else PMLowBar[1];
def ONATR = MovingAverage(AverageType, TrueRange(h, c, l), Length) * ATRMulti;
```