Squeeze Momentum Indicator wrong calculation

[Andre0711er]

Hi.

I just add the first unit test for Squeeze Momentum Indicator. I just compare calculated values with Tradingview data and they differ.

Following test data are used:
BTCUDST.P from Bybit
1 day interval

might be cool, to check. i don't see the problem yet.
here are the test:
https://github.com/Andre0711er/ta4j-extended/blob/main/src/test/java/org/ta4j/core/indicators/SqueezeMomentumIndicatorTest.java

I know, my changes, on code basis, based on ta4j 0.8-SNAPSHOT yet, but indicator itself aren't touched.

[Cypher01]

I checked my implementation and the values are indeed a little bit different than on TradingView, even though the "shape" looks correct, also the zero-line crossings seem to be correct.

Yet I couldn't find a bug in my calculation, but indeed LazyBear's original implementation has a bug. It uses the multiplier for the Keltner Channel for the calculation of the Bollinger Bands.

TradingView PineScript:
dev = multKC * stdev(source, length)
should be
dev = mult * stdev(source, length)

Maybe this is the reason for the differences.

[Andre0711er]

Question: Did we open up a Ticket for LazyBear. :-) Hehehe, but how?!

[Cypher01]

I think so, it would make sense. Afaik there is no issue reporting on TradingView, but there is a comment area below the indicator page.

I just noticed that the bug is known. The indicator was released in July 2014, and the bug was discovered in September 2014. The description starts with:

[--- Updated: Sep 29, 2014 ---]

Fixed a typo in the code where BB multiplier was stuck at 1.5. Thanks @ucsgears for bringing it to my notice.

Updated source: pastebin.com/UCpcX8d7

Use the updated source instead of the what TV shows below.

[---- Original Notes ----]
...

I wonder why the source code in TradingView was not updated, but I assume that this was not possible 10 years ago.

When I have time, I'll copy and paste the fixed code to a private indicator to compare the values. @Andre0711er You can also do this if you want.

I'll keep this issue open until we clarified the situation.

[Andre0711er]

@Cypher01 Might be a good idea, to add a comment inside the code. including reference to that page. This will help for the next person who to code review or comparing tests between code and tradingview.

Greets,

André.