Tradingview already offers a Fisher Transform. I compared your script with the build-in version from TradingView. It seems the signals are not identical:
LastBattle
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Ah. I should have searched for it beforehand, saves time making this script.
Anyway, you can't get the source code of the build in Fisher by TV. Take this as something bonus for you to build with :)
Learned something some Pinescript along the way too...
ChartArt
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I like that you created your own script version, because - as you said - it's not possible to play around with the build-in version without the source code.
LastBattle
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The build in ones seems to be mixed with some moving average or was it a rounding issue for my code? I'll check it out....
ChartArt
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The issue seems to be with your script. Hpotter has also created a Fisher Transform script and his version shows the same signals as the TradingView version. You can compare the code here: