Re: Tagged intervals (Was Branch & bound for not everywhere defined constraints)
"Arnold Neumaier" <Arnold.Neumaier@xxxxxxxxxxxx> wrote:
> Corliss, George schrieb:
>
>> Isn't the P1788 standard for the interval that DecoratedInterval would
>> decorate? That is, our class Interval is the SIMPLE interval. Sure, we want
>> it to be as rich and expressive as we can design, but we should expect that
>> in many applications, the expressive power will come from
>> application-specific decorations, so the core class Interval can remain
>> SIMPLE and FAST. Then applications that do not need decorations will enjoy
>> good performance.
>
> We need to specify what support 1722 should rerquire that enables
> programmers later to do with the decorated intervals whatever they want
> to do.
ABSOLUTELY, and I should have made that point. We DO want to include hooks
essential to building class DecoratedInterval. I do not really favor
simplest possible; I just oppose overly complicated.
As in most things, Truth lies somewhere between extremes.
> If no flags or equivalents for PossiblyUndefined etc. are provide
> then a user who wants to program decorated intervals that propagate
> a PossiblyUndefined decoration will have to do that the same way as it
> is done now, which means inefficiently and with lots of effort:
> every operation must be reprogrammed!
Violently agree.
I think one consequence of viewing P1788 as a basis for many classes
DecoratedInterval is to prefer the relative simplicity of a flag
PossiblyUndefined (or equivalent) to the relative complexity of multiple
NaIs, but I'm still listening to the arguments there.
George