By interpolating between values you can get excellent results with LUTs much smaller than 32KB. Will it be faster than the computation from op, that I don't know.
> if you use smaller data types than double or float. Even dropping interpolation worked fine,
That's kinda tautological isn't it? Of course reduced precision is acceptable where reduced precision is acceptable... I guess I'm assuming double precision was used for a good reason, it often isn't :)
About dropping the interpolation: Yes you are right of course. I was thinking about the speed. No noticable speed improvement by dropping interpolation. The asin calls are only a small fraction of everything.