> we are performing an rather imprecise and expensive acos() call No, the acos() call is not expensive at all. There is hardware acceleration.We can calculate

> we are performing an rather imprecise and expensive acos() call No, the acos() call is not expensive at all. There is hardware acceleration.We can calculate acos() with in 12 CPU instructions. https://git.musl-libc.org/cgit/musl/tree/src/math/i386/acos.s https://git.musl-libc.org/cgit/musl/tree/src/math/i386/acos....