Link between strategy and indicator

[YD777]

Generally speaking, what goes on behind the scenes when you use an indicator in a strategy? Take, for instance, the very basic OpenIsClose indicator from the tutorial:

[B]INDICATOR:[/B]
OnBarUpdate()
{
     Plot0.Set(Open[0] == Close[0] ? 1:0);
}

Let's say I don't have that indicator on a chart or active anywhere, but then use it in a strategy:

[B]STRATEGY:[/B]
OnBarUpdate()
{
     If OpenIsClose()[0] == 1
          //other code
}

What is going on? How does my indicator's code, which deals with a plot that doesn't even exist in the strategy, end up giving my strategy a useful value via the "OpenIsClose()[0]" statement?

[NinjaTrader_ZacharyG]

Hello YD777,

Thank you for writing in.

OpenIsClose() is a method call for the indicator OpenIsClose.

Simply, when calling an indicator from a strategy with its method call, the indicator will do its calculations based on the close prices, and then return the result of that calculation. The indexer, [0], refers to a barsAgo value. A value of 0 would be the indicator value for the current bar your script is evaluating. A value of 1 would be the indicator value for the previous bar. So on and so forth.

[YD777]

OK. So behind the scenes, an indicator object is created somewhere? And that same object is used for the entire run of the strategy?

[NinjaTrader_PaulH]

Hello YD777,

Thanks for your reply.

Yes, that is correct.

You may want to review this thread for further understanding: http://ninjatrader.com/support/forum...rs+efficiently

[YD777]

That thread is very useful, thanks for the link. Particularly, that link posted in the thread was the exact kind of think I was looking for:

http://web.archive.org/web/20100428224212/http://www.movethemarkets.com/downloads/rwt/rwt004/

I would suggest that this type of information be included in the standard help files.

[NinjaTrader_PaulH]

Hello YD777,

Thanks for reply and suggestion.