Re: does mod not work for constrained ranges anymore?

Hi Raphael,

On Tue, Jul 17, 2001 at 08:24:28AM -0400, Raphael Finkel wrote:
> The ECLiPSe banner with the version number and configuration
> (unless visible in the script):

Please do provide this information when reporting problems.

> 	Short description: In the previous version of Eclipse, I had no trouble
> 	using the arithmetic "mod" operator in constraints.  Now I get:

I think you will find that you are mistaken.  To the best of my knowledge,
it has never been legal in any version of ECLiPSe to have a variable in the
argument of a `mod' operator at the time the expression is evaluated.

Note that you can still express these kinds of constraints, but you have to
do it manually.  Normally it's not too difficult (X mod a #= Y can be
transformed to X + a * K #= Y with appropriate constraints on X and Y (and
maybe K) depending on how you want the mod to behave).  Note that this does
not work for #\= constraints though, because the system will just choose K to
make the constraint hold; in this case you may need several constraints
(e.g. X #\= Y, X + a #\= Y, X - a #\= Y).

Cheers,
Warwick