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Re: Putting features in vs. leaving them out, especially functions



On Wed, May 25, 2011 10:06, John Pryce wrote:

>   - I rather disagree with George on reverse operations. Constraint
> Programming seems
>     an important application (I know little about it) and it needs
> operations of
>     the form "enclose the set of all x in xx for which f(x) is in yy"
> where f is some
>     elementary operation. In CP applications I guess these are
> performance-critical;
>     if so, that seems a reason to have them in the standard.


>   Stuff like (1-cos x)/x^2: people to whom these are
> important are
>     competent enough to code them themselves; they are unlikely to be
> performance-
>     critical.

They are needed for the efficient implementations of slopes and
second-order slopes, which we use in our COCONUT global optization
environment almost as much as CP.