Re: Motion M0061.02 : YES
On 2014-02-28 09:19:18 +0100, Guillaume Melquiond wrote:
> The last paragraph of 7.5.4 is a bit restrictive too. It might well happen
> that two different implementations are just incomparable. I am thinking in
> particular of elementary functions; which one of two implementations is the
> most accurate presumably depends on the input domain (values close to zero,
> large values, etc) due to their having different argument reduction.
I think that linear ordering may be useful for the end user, and
the current "should" is OK. But IMHO, the ordering should just be
informative, and not necessarily linear: accuracy mode 1 > accuracy
mode 2 when in general f1(X) in included in f2(X), without a guarantee
that this is always the case. The idea is to inform the user that he
will generally get more accurate results by choosing mode 1 instead of
mode 2. The only guaratee is that for inf-sup types (when the hull is
unique), the tightest mode gives the most accurate results.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)