[gecode-users] diffn constraint for Gecode

[Sandro Pirkwieser]

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