Dynamically changing an indicators parameter

[Louis335]

Dear team,

I'd like to change the parameter of an indicator from within another indicator's OnBarUpdate(),
e.g. change the period of the SMA indicator by Ninjascript, determined by some logic of my current indicator, at the completion of each bar,

What would be the recommended approach ?

Thank you for your support throughout the year.
Louis

[NinjaTrader_Jim]

Hello Louis365,

Thanks for your post.

You could call the indicator dynamically in OnBarUpdate, modifying the indicator parameters as needed. For example, your hosting script can calculate a value for the Period needed for SMA, and then the hosting script can call the SMA with SMA(YourPeriodVariable)[0] in OnBarUpdate.

        protected override void OnBarUpdate()
        {
            int YourPeriodVariable = (CurrentBar % 2 + 1) * 10; // Some value calculated in hosting script
            Print(SMA(YourPeriodVariable)[0]);
        }

SMA syntax - https://ninjatrader.com/support/help...simple_sma.htm

Please let me know if I can be of further assistance.

[Louis335]

Thank you Jim.
Supposed I wanted to change the period of the SMA that has already been called as an indicator to a bar type on a chart; would it be possible to modify the period of the existing instance of that visible SMA indicator by NinjaScript rather than though the UI ?

[NinjaTrader_Jim]

Hello Louis365,

This would not be supported. While it may be possible to search for the indicator in the ChartControl.Indicators collection, it would not be supported to assign a new parameter programmatically.

You could consider having your parent indicator add a plot for what would be displayed by a child indicator, and then assign the parent's plot value to the output calculated from the called child indicator.

protected override void OnBarUpdate()
{
    int YourPeriodVariable = (CurrentBar % 2 + 1) * 10; // Some value calculated in hosting script            
    Values[0][0] = SMA(YourPeriodVariable)[0]; // Values[0][0] would need to reflect the plot added in this (parent) indicator    
}

I look forward to being of any further assistance.

[Louis335]

Thanks for the clarification, Jim.
Best, Louis