ZigZag issue

December 24th, 2020, 08:41 AM

Hello All!

I'm working on translating some code from Metastock to Ninjatrader 8.

So MS function TroughBars(1,C,2) finds the most recent (1) Trough with 2 percent (2) deviation from Close dataseries (C)and calculate number of bars since it.

Ninjatrader function ZigZag(Close,DeviationType.Percent,2.0,false).LowB ar(0,1,1000) does the same. (1000 - is look back period)

Should do. But actually it works different it seems, as you can see. Also it is clear that MS function is correct, but NT not.

Please, help to understand the origin of difference and how to fix it.
Or may be there is another way to calculate it exactly.

Thanks in advance

January 3rd, 2021, 07:10 PM

The MetaTrader indicator is repainting.It does not start counting from every low bar, but only starts counting when there is a final low. However, the final low can only be identified with hindsight knowledge.

Often it is not understood that the Zigzag indicator is a repainting plot itself. The last leg which is printed can be extended, and the new leg in the opposite direction is only drawn once the selected minimum deviation - 2 percent in your example - has been exceeded. Extension of the current leg requires redrawing the entire leg. Adding a new leg in the opposite direction requires drawing the new leg across several data points.

The NinjaTrader indicator does not wait until the final high point or low point is drawn, but starts counting from each preliminary swing high or swing low. It is non-repainting.
By the way you can easily created a repainting version of the LowBar function to match the MetaTrader algorithm.

In my opinion both concepts are insatisfactory for determining the size of a swing leg. There is a better way of doing this. I would count the number of bars of a swing leg from the revelation point (the price bar for which it is revealed that the prior high or low has becomes a final swing high or swing low) to the next revelation bar. To understand that concept, it is useful to add a two percent trailing stop to the zigzag indicator. The chart attached shows the MetaTrader count which can only be identified with hindsight, and compares it to the actual direction of the current swing leg, which only changes direction once the 2% threshold has been exceeded.

It is all about repainting or non-repainting plots.

ES 03-21 (D-Renko T20) 2021_01_04 (01_08_16)

ZigZag issue

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ZigZag issue