Zampelli Stephane wrote: > Suppose one has a non-monotonic propagator P, because the propagator > uses an approximation (of a NP-Hard problem) of the pruning. > How can Gecode accomodate of this situation? > Does this mean that recomputation cannot be used?
Recomputation will almost certainly fail (i.e., segfault or throw an exception) if non-monotonic propagators are present. > Is the result correct if the recomputation is not used (full copying, > c_d=1)? Yes. > What about executing the propag P after the fixpoint of all other > monotonic constraints? That looks like a solution in principle, but won't work in practice. The problem is that the space is not going to be stable (i.e. at a fixpoint) after running P. Spaces in Gecode can only be copied at fixpoints. You could iterate the normal fixpoint computation and the invocation of P until you reach a mutual fixpoint. Still, this is not guaranteed to work with batch recomputation, where only one fixpoint is computed for each backtrack. We have thought a bit about how to accomodate non-monotonic propagators, but it's really not easy. Cheers, Guido _______________________________________________ Gecode users mailing list [EMAIL PROTECTED] https://www.gecode.org/mailman/listinfo/gecode-users