# [racket-dev] Sublinear functions of superfloat numbers

I've noticed something interesting about the `log' function. Check out
this interaction:
> (real->double-flonum #e1e400)
+inf.0
> (log #e1e400)
921.0340371976183
It's obviously not just converting to flonum first; it's likely doing
some kind of argument reduction internally.
`sqrt' operates on superfloat numbers when they're perfect squares, and
`sin' doesn't at all:
> (sqrt #e1e400)
[1e200 written out]
> (sqrt #e1e401)
+inf.0
> (sin #e1e400)
+nan.0
I have two questions:
1. I think I have the Mad Skillz to make these work by wrapping the
primitives with something that does argument reduction. Should I? (It
should be especially interesting to do `sin', requiring an
arbitrary-precision `pi' constant. Woo!)
2. Under what circumstances should sublinear `math' library functions do
this? All of them?
Neil ⊥