[gecode-users] rtest_eq_dom doesnt lead to RT_TRUE !?!?!

[Guido Tack]

Hi.

> I found a strange behavior of the Gecode::rel function using IRT_NQ as
> an reified constraint.
>
> I used 2 variables with the following domains:
>
> d1 = (1)
> d2 = (0,2)
>
> also I ve got a reified constraint like that
>
> rel(home, d1, IRT_NQ, d2, isNQ, ICL_DOM)
>
> so isNQ should be true if d1 an d2 are unequal!
>
> BUT: isNQ is NOT assigned!

Giving ICL_DOM as a parameter does not always mean that domain consistency is 
enforced. It only means that propagation will not be stronger than the level 
given.
For (dis)equality, of course domain propagation is easy - nevertheless, it is 
significantly more expensive than bounds propagation. That's why it is 
currently not implemented.

Cheers,
	Guido

-- 
Guido Tack
Programming Systems Lab, Saarland University, Germany
http://www.ps.uni-sb.de/~tack