Re: Motion 46: finalise interval literals, amendments
Replying to Dima, Vincent wrote:
> > Arbitrary precision library is not a trouble.
> > Conversion of decimal string to binary floating-point with
> > correct rounding already requires arbitrary precision library.
>
> Multiple precision, yes. But arbitrary precision is not necessary,
> as the needed precision is bounded, AFAIK.
True for decimal string input (max precision needed for binary64 is
less than 800 digits), but it gets tricky for rational input, which
was the actual context here.
Consider a/b to be an exactly-representable FP number (e.g. b is a
power of two and a is less than 2**53), and consider (a*(K+1))/(b*K)
for K very large, vs (a*(K-1))/(b*K).
Michel.
---Sent: 2013-07-09 15:48:59 UTC