Indicator that calls itself

[Picita]

Good day to you all,
Is there an instruction that invokes the indicator that is being built of the precedent bar?

similar to the instruction "PREV" of MetaStock:

"Self Referencing Formulas Using PREV
The PREV constant allows you to create self-referencing formulas. A self referencing formula is one that is able to reference the "previous" period's value of itself.
For example, the following is an example of a self referencing formula:
((H+L+C)/3) + PREV
This simple formula divides the high, low, and closing prices by 3 and then adds this value to yesterday's value of the ((H+L+C)/3)."


thank you very much

[NinjaTrader_Austin]

Hi Picita, there is no PREV function, but you can certainly access the previous value of an indicator. The EMA indicator would be a good example of this, it uses Value[1] to get the last value of itself, which is then used in the new calculation.

If you wanted to sum the close of a bar series, for example, you could do something like this:

dataSeries.Set(Close[0] + dataSeries[1]);

[Picita]

I think the situation is more complicated
because in this case there is a call to the function itself:

in Metastock
pr:= (H+L)/2;
sp:= (pr+(2*Ref(pr,-1))+(2*Ref(pr,-2))+Ref(pr,-3))/6;
cycle:= Mov(Power(1-(.5*a),2)*(sp-(2*Ref(sp,-1))+Ref(sp,-2))+(2*(1-a))*PREV-(Power(1-a,2)*Ref(PREV,-1)) , a*1000,S);


in this case
PREV = cycle[1]

[NinjaTrader_Austin]

Picita, we can't provide support for MetaStock features/methods. In this example, Ref() just pulls a previous value from some "data series" (not sure the metastock name for it).

You could basically re-write the code you just posted with cycle[1] instead of PREV, as you've mentioned. If you need the sp value from two bars ago, you could do sp[2] instead of Ref(sp, -2).

[koganam]

The syntax is certainly different: the functionality is the same. The previous value of any indicator to the CurrentBar is the reference PlotSeries[1], or, alternatively, Value[1] if there is only one plot.