When to use Update() Method

[tornadoatc]

Hello,

I am trying to understand when it is necessary to call the Update() Method for Properties being exposes from an Indicator.

I have an indicator that exposes a List<Objects>. The List is populated from logic within the same indicator. I expose the Object with a simple getter :

[Browsable(false)]
        [XmlIgnore]
        public List<MWBSTRedWavePattern> L_RedWavePatterns
        {
            get {  return RedWavePatterns; }
        }

While I don't believe the Update() Method is required prior to the return in this scenario, I want to understand when it is required?

Thanks,

[NinjaTrader_ChelseaB]

Hello tornadoatc,

Update() works similar to TriggerCustomEvent() to ensure all series are up-to-date and OnBarUpdate() for all hosted scripts has been run, but instead of being from another thread, this is from a calling host script.
https://ninjatrader.com/support/help...nt8/update.htm

If you don't need information from OnBarUpdate() or from a series, this is not necessary to call.

[tornadoatc]

Hello tornadoatc,

Update() works similar to TriggerCustomEvent() to ensure all series are up-to-date and OnBarUpdate() for all hosted scripts has been run, but instead of being from another thread, this is from a calling host script.
https://ninjatrader.com/support/help...nt8/update.htm

If you don't need information from OnBarUpdate() or from a series, this is not necessary to call.

So my understanding is that any exposes property that is not populated from the Values[x] should call Update() from getter. If values are already upto date then no performance penalty as it would not be called if properties are up to date.

Is this correct?

Furthermore, this sentence from the link generates questions regarding realtime vs historical: "When indicators are embedded (called) within a NinjaScript strategy, they are optimized to calculate only when they are called upon in a historical backtest." So what is the difference in behavior between historical and realtime bars regarding the need for Update()?

Thanks,

[NinjaTrader_ChelseaB]

Hello tornadoatc,

If the property is set in OnBarUpdate() and is not a plot, then use Update() to run OnBarUpdate() to update the value before it is returned.

In historical, an indicator doesn't actually run through the historical data until it is called and then it will process all of the historical data (pretty much at once) for efficiency. In real-time it will calculate even when not called.

However, if the script needs a value updated in OnBarUpdate() before being returned, use Update() in both historical and real-time.