Re: Motion P1788/M0013.04 - Comparisons - Overflow / Infinity
Ian, 1788:
On 9/20/2010 10:03, Ian McIntosh wrote:
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One problem with that is that you don't know whether you're dealing with an infinite value or with an overflowed value. You need to know to get the semantics of subsequent operations correct.
IEEE Infinity * 0 = NaNQ
NaNQ is the right answer for Infinity resulting from nonzero/0, but should be 0 if the Infinity was the result of an overflow instead. Clearly the two meanings of Infinity need to be distinguished.
Proposed nonzero / 0 = Infinity
*Proposed overflow on any operation = Overflow*
If Interval Arithmetic was based on IEEE 754 with Overflow added, some of the operations would be simplified because they would not have to handle special cases.
As it stands now, we wouldn't base things STRICTLY on 754, since motion 3 passed, and since 754 treats
Infinity as a number. Since motion 3 states that we are only dealing with reals, we would be interpreting
the symbol Infinity the same as overflow, n'est pas?
Baker
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