Re: Motion 6
On 2009-09-16 18:35:54 -0700, Dan Zuras Intervals wrote:
> In particular, the semi infinite sets have no representation
> in midrad. An important subset in need of representation.
That's not a problem. If you have a semi-infinite set, this means
that the error bound is infinite. So, this isn't much different
from the whole set R of the real numbers.
> These two sets are not interconvertable
Well, if need be, you can still do conversions that just preserve
the inclusions.
> Still, this does not mean that midrad won't have a place in
> intervals. In particular, in many of the algorithms for
> which you use it, you likely choose a midrad for reasons of
> computational efficiency. And for those problems that are
> sufficiently intractable as to require such an approach, I
> would have every expectation that a midrad would be used by
> the implementor internally to accomplish that.
Not just internally.
> If you feel that such a thing needs to be standardized for
> that reason alone, I would support it. But, if so, I would
> like to make the language of our support to be written in
> such a way that means we are not recommending midrad be used
> for 'general' interval problems.
Perhaps.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/>
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Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)