Dear members of the GECODE mailing list, I am trying to model a surgery scheduling problem as a constraint programming model. The problem consists in scheduling a set of surgeries to operating rooms across a one week planning horizon. My testing instance contains 316 surgeries to be scheduled into 10 timeblocks (OR/shift) of 3 operating rooms. Each surgery has a determined surgeon and estimated duration. In some days of the week the 3 ORs are working in parallel and we have to schedule the surgeons among them. The goal is to maximize the number of surgeries scheduled.
I have tried to model the problem using the binpacking constraint, however it is different from a binpacking problem as the number of bins is fixed and I have to select a subset of items, it is more like a knapsack problem, more specifically a multiple knapsack problem. Does anyone know if I can use the binpacking constraint limiting the number of bins and not packing some items? I have also tried to model the problem using the cumulatives constraint, however I have multiple resources of two types, more specificaly 3 ORs and 10 surgeons. I was trying to use cumulatives to deal with the multiple ORs using limit 1, but I am not sure if I can use cumulatives at the same time to schedule the surgeons, also limited to one. The problems is like a multiple knapsack problem with parallel resources. Could you point me to the more efficient way to model this problem? I have modeled the problem in a naive way, but it is not efficient, so I would like to use different constraints to improve performance. Best regards, Fabrício Sperandio
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