[eclipse-clp-users] Union of real intervals (was Re: Variable Bound Symbols in Embedded)

Meriem Djefel wrote:
> Hi all,
> I want to know can I declare a real variable with a domain union of 
> intervals.
> In the documentation , we have *interval_union / 
> 3*..........lib_public/intervals 
> <http://87.230.22.228/doc/bips/lib_public/intervals/index.html> but 
> there is no description! Is it an obsolete Library?
> 
> Thanks.

Your posting does not seem to be related to the thread you are posting 
to -- you should start a new thread in such a case; I have started a new 
thread (and your message was delayed because you are not subscribed to 
the list, it needed to be manually approved).

I assume by `real variable' you mean a variable with a real interval 
from lib(ic) (a variable with a finite domain can only take integer 
values in lib(ic)). Unlike finite domain, a real interval cannot have 
holes in the interval, so you cannot have an unrestricted `domain 
union'. The closest to a union is to take the largest of the maximums of 
your intervals and the smallest of the minimums of your intervals and 
make these the maximum and minimum of your new interval.

The libraries/files in lib_public are user contributions to ECLiPSe (the 
'public' comes from the days before ECLiPSe was open-sourced, when only 
the source in lib_public were distributed). Some of these contributions, 
including the intervals.pl you refer to, is quite old -- if you look at 
the file, you will see that it dates from 1987. It is completely 
unrelated to the real interval available in lib(ic).

The documentation in the reference/bips manual you are referring to is 
generated from the comments documentation that you can put into your 
ECLiPSe source file. There is no description for intervals.pl because no 
comment documentation exist for intervals.pl. It is a good idea to add 
such documentation to any code that you intend to be used by other 
people, but the lack of such documentation does not necessarily mean the 
code is obsolete.

Cheers,

Kish

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