[Haskell-cafe] Default implementation of Floating (**)
ietf-dane at dukhovni.org
Wed May 19 19:39:13 UTC 2021
On Wed, May 19, 2021 at 02:08:06PM -0300, Fabrício Olivetti de França wrote:
> > I guess he expects (-2)**(-2) = 1/4.
> > But defined this way, (**) would be rather discontinuous
> Indeed, that's what I was expecting. For Float and Double (-2)**(-2) =
> 1/4, but for the interval arithmetic library that uses the default
> implementation, it doesn't.
This shows the difference between the math library's
pow(x, y) and exp(log(x)*y)
Indeed pow(x, y) appears to attempt to detect integer-valued floating
point exponents and take the interger-exponent code path in that case.
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