Sorry i wasnt more clear. There is two aspects to this. The constraint is pretty expensive to propagate ( this is a different constraint than the one i send you the paper about btw, im using Gecode for two separate projects ), for this i dont care if its placed at the very end. That property is just something i wanted in order to tell whether the constraint im adding is pruning values that would otherwise not be pruned in that search node. Ie, if the other constraints have stabilized and i then prune some values, i know these values would not have been pruned by the other propagators unless a branching occurred.
The other constraints involved are distinct's and they hopefully dont provide a cost of PC_CRAZY_HI :) Regardless, this concept of staged propagation sounds interesting, i will take a more thorough look at the paper. Regards, Peter Tiedemann On 10/04/07, Christian Schulte <[EMAIL PROTECTED]> wrote:
Well, you cannot rely on that no other propagator does it. At least not in real life... What are you trying to do? If you have a propagator composed from a cheap and an expensive stage you might want to consider staged propagation. Just see the paper I mentioned before. We use it regularly in Gecode to great benefit. Cheers Christian -- Christian Schulte, http://www.imit.kth.se/~schulte/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Peter Tiedemann Sent: Tuesday, April 10, 2007 3:40 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: [gecode-users] Ordering of propagators > What do you mean with how the cost function is used? Could you > elaborate, please? I was just wondering how the cost affected the ordering, but it seems that this is explained in the reference you just gave me. From a quick scan of it, it would seem that if i choose the highest cost (and no other propagators do the same), then i am in fact 100% sure that my propagator will only be asked to propagate when all other propagators have stabilized, which is exactly the effect i was hoping for. Thanks for the quick answer, you guys really have short response times :) Regards, Peter Tiedemann
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