Use Open[-1] in NT 8 Error

[ale.pari]

Hello, I build my strategy on NT7 and now I try migrate this, But I have a problem whit the Open[-1]. When I run with historical data it shows this error:

Strategy 'Opti': Error on calling 'OnBarUpdate' method on bar 62: You are accessing an index with a value that is invalid since it is out-of-range. I.E. accessing a series [barsAgo] with a value of 5 when there are only 4 bars on the chart.

I searched about this but I couldn't resolve the problem. I use the Open[-1] to compare whit the Open[0] in a Conditional.


Help plsss I am lost!!!

[traderpards]

Hello, I build my strategy on NT7 and now I try migrate this, But I have a problem whit the Open[-1]. When I run with historical data it shows this error.

The way indices work in Ninja-land, is you use [0] for the current bar that just closed, assuming your Calculate variable is OnBarClose. (it gets a little complicated if Calculate = anything else). For the next bar in history, that is the next bar before the current bar that just closed, the index is 1. The index for the bar after that is 2, then 3 and so on throughout the past.

You are actually technically asking for information on a bar that is in the future where no information exists yet. In programming-land, arrays don't have indexes with a negative number and that's why the application threw an out-of-bounds exception.

I would guess you meant to compare the current bar with the bar before it, so you would want to compare [0] with [1].

[agenor]

Hi ale.pari,

I had a similar problem.

Try to compare Bars.GetOpen(CurrentBar+1) with Open[0]