Note: With this refactoring, `math/utils' no longer depends on `rackunit'.
* (flexp2 x) computes (flexpt 2.0 x) but in about 1/3 the time for integer
`x' using a lookup table. Written for exact argument reduction in `fllog2'
after discovering that (flexpt 2.0 x) was the main performance bottleneck.
* (fllog2 x) computes (/ (fllog x) (fllog 2.0)) with near perfect accuracy.
Invented an algorithm to compute it with at least 8 extra bits before
final rounding; quite pleased with the result. Needed `fllog2' to ensure
(fllogb 2.0 x) would be exact when `x' is a power of two.
* (fllogb b x) computes (/ (fllog x) (fllog b)) with better accuracy, and
also handles limit values in a way that's consistent with the mathematical
limits. When those are ambiguous, it's consistent with `flexpt', which
follows IEEE 754 and C99. Otherwise returns +nan.0. See docs for details.
* `bflogb' is currently just for testing `fllogb'.
* Refactored FPU testing and documented it. So far, the only documented way
to do it is by calling `test-floating-point', which runs a comprehensive
deterministic+randomized suite of tests and returns a list representing
failed tests. I'll document individual tests after I document flonum
expansions and result/error functions like `fl+/error'.
* Added `fllog2' and `fllogb' to the flonum tests.
