Mario Ruthmair

Hi Dilip, I can spot two issues: I think your depot is 0 according to the definition of "customers" and "total", but in your formulation you assume customer 1 to be the depot. In the last set of c...

Hi Dilip, Your code for this particular model part looks correct, although you might write the quicksum in a more efficient way: m.addConstr(quicksum(x[i, j, k]*dist_matrix[i,j] for i in total for...

Hi Dilip, You can reformulate the min-max objective by introducing a single additional continuous variable z, and then move the tour distance calculation to a set of constraints, i.e.: $$\min z$$ $...

Hi Lorenzo, You said that you are calling Gurobi in a separate thread. If you have a reference to the model object available in your main thread then you could just call model.terminate() from ther...

Hi Mr. Satender, You could create a one-dimensional binary matrix variable including both variable sets x and z, and then change the type of the x variables to CONTINUOUS afterwards, as demonstrate...

Hi Michael, First of all, which of the constraints and/or variables of the formulation from the other post did you remove such that you get integer solutions in the MIPSOL callback that contain sub...

Hi Michael, If the dual bound of 161 is weak, you might think of improving your model. The fact that you have to open at least one DC could be directly added as constraint, i.e., sum_i y_i >= 1. Ad...

Hi Michael, In general, small changes of the model can have a huge effect on the performance, we observe this behavior regularly. Do you have an idea whether the optimal value for the second model ...

Hi Yansong, Note that the default lower bound for a variable is 0.0, so the first and third code block is more restrictive on the lower bound than in the second one, see the addVars() description. ...

Hi, Are your facility variables y one or two dimensional? They are created for each facility but they seem to be used in the second set of constraints for each facility and product?If they would be...