Usage is as simple as HistVolAny(numberofbars)[0].
The other histvol indicator only lets you find x day (session) moving historical volatility while in a minute or smaller timeframe.
You may of course combine the use of the two, but this one gives a more accurate (and volatile) measure of HV possibly in a very short time period. (Fascinating and useful to know the practically instantaneous HV when entering a trade) In some ways this result could be correlated to bollinger band sizes as a percentage of the instrument.
Comment