Ronald van der Velden
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Recent activity by Ronald van der Velden-
Hi Mike, One use case could be, when you have a MIP model but want to calculate dual values (see this question). Those are not available for a MIP model, but when you fix all integer variables, the...
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Official comment Hi Yongtao, You can find suggestions in our article How do I resolve the error "Model is infeasible or unbounded"? ; one possible reason might be that your model is not infeasible but unbounded. Ki...
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Hi Sudheer, Here's a few more thoughts. Unfortunately we cannot go much further with modeling assistance, but other users of this community forum might be happy to jump in. If the number of loads ...
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Dear Sudheer, Should this problem be approached as a vehicle routing problem (VRP) where the goal is to optimize the routes and truck assignments for deliveries, or should it be modeled as a logis...
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Hi Rui, Just to be sure - Unless you're using the solution pool functionality, Gurobi does not necessarily return all optimal solutions. In general, if you feel a solution should be returned (and c...
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Hi, My first guess would be that there is a problem with build_RMP. I believe you're constructing a completely new model in each iteration, which could be a bit slow and makes it a bit harder to co...
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Hi Keyu, Thanks for posting here! In your example, all copies of the model live in the same (default) Gurobi environment, which is not thread-safe. Each model should live in its own, dedicated Guro...
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Hi Julia, If the problem is a minimization problem and all you do between iterations is adding a column, this should not happen indeed, since the optimal solution from the previous iteration is sti...
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Hi Sompol, Actually I believe the problem is not in your own code, but in Pyomo. It looks like this version of Pyomo calls a Gurobi function that has been removed in version 12. However, I don't se...
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Hi Shesha, Then it comes down to debugging. Your next step would be to find the (i,j) and (k,l) pair that overlap and then request/print the corresponding variable values including the AUX variable...