Re: A question Re: Level 1 <---> level 2 mappings; arithmetic versus applications
On 2010-07-01 06:08:54 -0500, Ralph Baker Kearfott wrote:
> However, I can now see what I think is Dan's view on the subject:
> it might be better to have just one such interval type, because
> multiple interval types built on the same floating point type
> (presumably most often an IEEE double) would weaken the standard
> in the sense that we would still have a proliferation of arithmetics,
> making reproducibility and portability more difficult. I'm not sure
> two interval types can be avoided, however, if we have strict
> accuracy requirements and require both mid-rad and inf-sup. We may
> need to make a decision or whether we want two types or to relax
> the accuracy requirement. If we relax the accuracy requirement and
> require both mid-rad and inf-sup, it may be difficult (or impossible?)
> to define the standard to ensure cross-implementation uniqueness
> (i.e. reproducibility) of results of operations, even at level 2.
I think that the standard should allow an implementation-defined
level 2, and some requirements would apply only for an inf-sup
level 2.
That's also why the standard should specify the operations at level 1
if possible.
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Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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