This is an awesome reference, thanks. I'll be using a few of these. The pi calculation uncovered a rainbow weakness: rainbow relies on java "long" integers for 'int types; but these are 64-bit signed integers and the algorithm fails at the 5th digit. So I'll need to think of a way to incorporate arbitrary-precision maths before I can run this benchmark. One thing is certain: using java's BigXXX family of numeric types is going to hurt.