Mario Ruthmair

Hi Michael, The examples should mainly demonstrate how lazy callbacks (or other features) work within Gurobi. Computational efficiency of the subroutines, as the method subtour() here, is not a pri...

Hi Danial, Unfortunately, due to US export laws, we cannot provide Gurobi software to users while they are located in Iran, irrespective of nationality or origin. This is not a decision made by Gur...

If the time window of some customer has been set in a way that does not allow the vehicle to go back to the depot before the time horizon ends, then it could be infeasible. The time horizon can be ...

Hi Vamsi, Are you saying that the solution for the shown code and model is correct but for different input data you get the same solution? This sounds weird.  We recommend writing the formulated mo...

Hi Taposh Kumar, Several model components are missing that model the trucks' routes in your VRP with time windows. Here are Jupyter notebooks that discuss different ways to model the Capacitated VR...

Hi Dániel, There are several solver parameters that focus on finding feasible solutions while proving optimality is only the secondary goal: MIPFocus=1: search focus on finding good solutions No...

Hi Nan, If the models are completely different from each other and you have to create them from scratch in each iteration, then you should create a new model at the beginning of your loop iteration...

Hi, I am unsure if I understand your case, but let me try to rephrase it: The solutions returned by the solver are not optimal. You can generate solutions that further improve the objective value. ...

Hi Sajjad, Unfortunately, you cannot modify the model in callbacks during optimization. The algorithm requires that the initial model is complete. Otherwise, it would not be correct. There is the p...

I just solved an LP with barrier and was able to query successfully the attribute "DualResidual" after the optimization finished. Could it be that your final state was not "Optimal"?