[std-interval] Comments on the Interval Standard Proposal

R. Baker Kearfott rbk at louisiana.edu
Sat Sep 30 21:50:27 PDT 2006


At 01:26 AM 10/1/2006 +0200, Gabriel Dos Reis wrote:
>Sylvain Pion <Sylvain.Pion at sophia.inria.fr> writes:
>
>| Gabriel Dos Reis a écrit :
>| > | For implementations which do not support infinity, how do you check if
>| > | an interval is bounded ?  Currently we can't.
>| > Hmm, I'm unclear about this one.  If the implementation does not
>| > support infinity, does not it follow all intervals are bounded?
>| 
>| I was thinking that implementations could store extra data members
>| specifying if a bound is infinite.  You can't return it through
>| .lower(), because the floating-point type does not have a value
>| for infinity, but is_positively_bounded() can return the
>| information.
>
>Aha.  So, is it accurate to summarize the issue as to how to support
>unbounded intervals even where the implementation has bounded
>arithmetic for scalar arithmetic types?
>
Oh, I see:  Intervals can support such arithmetic when the 
floating point (presumably hardware) does not.  Hmmm....

Baker

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R. Baker Kearfott,    rbk at louisiana.edu   (337) 482-5346 (fax)
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Department of Mathematics, University of Louisiana at Lafayette
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