Re: Branch & bound for not everywhere defiend constraints
On 2009-09-07 10:36:36 +0200, Arnold Neumaier wrote:
> Vincent Lefevre schrieb:
> >On 2009-09-02 11:26:21 +0200, Arnold Neumaier wrote:
> >>Vincent Lefevre schrieb:
> >>>One could also have a flag attached to the returned interval.
> >>>Alternatively, one could have a function telling whether X' is
> >>>included in the domain of f.
> >>The latter can in general be found out only by evaluating;
> >>so this would double the work whenever one needs both the
> >>evaluation and the domain check.
> >
> >I would have said the opposite, i.e. that the latter doesn't need
> >evaluation in general. For instance, if the domain is R, then the
> >result is always TRUE. For the division, the result is TRUE iff
> >the second argument doesn't contain 0.
>
> I meant the domain of a whole expression.
OK, but then, this is out of the scope of the standard, isn't it?
But of course, if one wants to allow user-defined functions with
complex domains to have exactly the same interface as "common"
functions (whose domain should be known without much work), then
I agree.
> >This is what I've said: a flag *attached to the returned interval*.
>
> I had intended to say something slightly different:
> _all_ flags attached to the returned interval.
I agree that all flags should be handled in the same way (I assumed
that there existed only one flag under the context of this thread).
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/>
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