[gecode-users] Ordering of propagators

[Peter Tiedemann]

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 <cschulte at kth.se> 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: peter.tiedemann at gmail.com [mailto:peter.tiedemann at gmail.com] On Behalf
> Of Peter Tiedemann
> Sent: Tuesday, April 10, 2007 3:40 PM
> To: cschulte at kth.se
> Cc: users at gecode.org
> 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
>
>