@ustk
python, julia or matlab is your friend.
There are many scientific libraries for LUT generation, which can do curve fitting and other clever thingies.
I have an entire custom app built in python that can reverse engineer waveshapers from any linear shaper vst. I've reverse engineered many algorithms automatically using this tool.
BTW, use JuceVectorizedMath if using c++
You can do multiply add operations on a whole buffer. Efficient.