Hi, Co-incidence: I have been adding a naïve (but better than the decomposition) version of the constraint to Gecode recently. I will move that code to the trunk this week (there are still some glitches to fix before that).
The plan is to eventually improve to a state-of-the-art implementation. Taking code directly from Jacop into Gecode will not work due to their license. Maybe you would even be interested to contribute? At least you would have a nice structure to start from. We will release soonish a new version that will incorporate that but there are more things to be done before a release. Best Christian -- Christian Schulte, KTH, web.it.kth.se/~cschulte/ -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Sandro Pirkwieser Sent: Wednesday, May 25, 2011 9:01 PM To: [email protected] Subject: [gecode-users] diffn constraint for Gecode Hello, I'm using Gecode to tackle a 2D packing subproblem inside an optimization problem. The subproblem is about packing rectangles (for the meantime without rotation) into a given larger rectangle and many instances of moderate size need to be solved. Fortunately I was able to start with the perfect-square example, where the adapted variant already performs quite good (using the cumulatives constraint). Also enabling branching on intervals yielded a speed-up. Now I was wondering if someone of you already implemented a suitable diffn constraint (see http://www.emn.fr/z-info/sdemasse/gccat/Cdiffn.html) in Gecode. In this way the non-overlapping part would (presumably) be tackled more efficiently and give an additional performance boost. Do you think having a look at the diff/diff2 implementation in JaCoP is useful for implementing it in Gecode? Thanks! Best regards, Sandro _______________________________________________ Gecode users mailing list [email protected] https://www.gecode.org/mailman/listinfo/gecode-users _______________________________________________ Gecode users mailing list [email protected] https://www.gecode.org/mailman/listinfo/gecode-users
