Re: fwd from Jim Demmel: More on repeatability
On 2011-08-18 14:01:38 +0200, Vincent Lefevre wrote:
> On 2011-08-18 13:30:31 +0200, Arnold Neumaier wrote:
> > On 08/18/2011 12:04 PM, Vincent Lefevre wrote:
> > >The main problem can be the performance on some functions, e.g. for
> > >sin/cos/tan on large arguments. One solution would be to return [-1,1]
> > >for sin and cos when the argument is large enough.
> >
> > This wouldn't be an optimal rounding if the argument is [realmax,realmax].
>
> I know, but there isn't much choice if for instance, realmax ~ 2^64.
Oops, I meant Exponent(realmax) ~ 2^64, i.e. realmax ~ 2^(2^64).
> However, for the IEEE 754 basic formats, correct rounding should
> be OK if reproducibility is a must.
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Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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