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Re: Request for motion [Fwd: Input from IFIP WG 2.5 to IEEE Interval Standards Working Group]



Arnold

On 10 Sep 2009, at 12:25, Arnold Neumaier wrote:
Dan Zuras Intervals wrote:
	If we are to pursue this at this time, please include accurate
	versions of all of sum, dot product, sum of squares, & sum of
	absolute values for all supported precisions.
...
I think only interval-valued results for noninterval inputs should be provided by the standard. Then there are no problems.

If some element is NaN or two terms in the sum are +inf and -inf,
the result should be the empty set; otherwise the tightest enclosing
interval of the exact result should be returned.

Am I missing something? Suppose we implement as you say, "interval- valued results for noninterval inputs", and just ONE term of the sum is, say, +inf, the rest being finite numbers. Then the result is +inf, but since P1788 is based on the reals, there is no interval that encloses this. What to do?

John