Hi all, I have a modeling/implementation question that maybe somebody has faced before, or that gecode developers could help me answer. I'm trying to implement a symmetry-breaking strategy that works when the search engine backtracks. I have a set of items that need to be allocated in a set of bins (bin-packing problem) and I branch over the items to find for each item a possible bin where it can be allocated.
When it is no possible to allocate an item in a selected bin (the search engine backtracks), i'd like to avoid trying to allocate the item in bins with the same available capacity as the bin that has just been discarded, since i already know it won't be possible. This should be as simple as identifying the bins with the same available capacity as the bin selected by the branching, and posting rel constraints to remove these bins from the domain of the item. I thought about doing this in the commit method, and instead of just posting one constraint to remove the bin that couldn't allocate the item being considered, also remove the bins with the same available capacity. The problem is that if i follow this approach i think i'll screw up recomputation , and that's just if i'm able to get the information i need to the commit method. Do you guys have any suggestions on how to implement this in gecode? any hints are welcome. Best, Alberto _______________________________________________ Gecode users mailing list us...@gecode.org https://www.gecode.org/mailman/listinfo/gecode-users
