Re: Motion 46: finalise interval literals, 2nd try at "ulp"
On 2013-07-12 18:52:00 +0100, John Pryce wrote:
> So the definition for interval literals needs stating more
> carefully. It is really ulp(s,b) where b is a radix and s is a
> string representing a number in radix b without exponent. Ignoring
> any weird coding that says what b is, s has the form
> {sign}? ( {b-ary digit} | {point} ) +
> where there is at least one b-ary digit and at most one point ".".
>
> The "last place" of s is an integer p ≤ 0.
> If there is no point, or no digits after the point, then p=0.
> Otherwise p = -n where n is the number of digits after the point.
>
> The "unit in the last place" is ulp = b^p.
>
> Example: 0 and 0. have ulp=1, while .0 and 0.0 have ulp=1/b.
>
> Does that do?
Yes, seems fine.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)