On Fri, Oct 10, 2008 at 5:55 AM, David Przybilla <[EMAIL PROTECTED]> wrote: > Is there any document about how to use/implement Advisors in Gecode?
There is no introductory documentation. The design and reasoning behind advisors is reported in "Advisors for Incremental Propagation" [1]. For examples of how to use advisors there are some propagators that use them, for example the layered graph propagator (for regular constraints, gecode/int/extensional/layered-graph.icc), the GAC-Schema propagator (table constraints, gecode/int/extensional/incremental.icc), and the Boolean linear in-equation propagator (gecode/int/linear/bool-int.icc). In general (not knowing what you intend to use it for), the typical case is that a set of subscriptions to variables are replaced with a corresponding set of advisors that react to modifications to the variables. Typical use-cases might be to maintain some propagator state and/or avoid scheduling the propagator when no propagation can be done. There are a couple of things to keep in mind when writing a propagator that uses advisors: * The advise-function should follow the information in the documentation [2] * The delta-information may be empty if the modifications to the variable is very complex. * The propagator should take care to recognize when it is subsumed. * If an initial run of propagation is needed, a propagator not using subscriptions needs to schedule itself on creation. * Advisors are maintained in propagators using a Council, and if needed are accessed using the Advisors-iterator. And also, as always when doing a propagator, be sure to test it thoroughly. Cheers, Mikael [1] http://www.gecode.org/paper.html?id=LagerkvistSchulte:CP:2007 [2] http://www.gecode.org/gecode-doc-latest/classGecode_1_1Propagator.html#93f6a78f3613c3afa9a7afe7984da89d -- Mikael Zayenz Lagerkvist, http://www.ict.kth.se/~zayenz/ _______________________________________________ Gecode users mailing list [EMAIL PROTECTED] https://www.gecode.org/mailman/listinfo/gecode-users
