Re: Siegfrieds recent paper
On 2012-01-06 13:46:27 +0100, Vincent Lefevre wrote:
> On 2012-01-05 15:33:13 +0100, Siegfried M. Rump wrote:
> > For example, in measure theory people are used to define inf-inf=0. In
> > IEEE754 the choice was inf-inf=NaN. One could also have defined
> > inf-inf=0 with a flag; but the majority of numerical analysts would
> > prefer (or expect) inf-inf=NaN.
>
> IEEE 754 is not for measure theory. The IEEE-754 inf is first a
> consequence of overflow, not the inf of measure theory. In this
> context of floating-point, NaN was the right choice for inf-inf.
BTW, on a similar subject, the middle of [-inf,inf] should be NaN
(IEEE 754) or undefined. Though 0 appears as the center of symmetry
at Level 2, it is not the only one at Level 1 (every real number
could be seen as the middle).
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Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)