Tobias Achterberg

Having an empty callback should not deteriorate performance much. If you are using Python, then of course a callback means that we need to always step into the Python interpreter, but even this sho...

It is an interesting coincidence that you are running into this issue now, because I am currently trying to improve this behavior of Gurobi. I think that I found a nice way to do so and will pick u...

Hi Thomas, Jaromils suggestions are of course perfectly fine. But I wonder why it is bad for you to just set a time limit that fits to the difficult scenarios for the overall multi-scenario solve. ...

Thanks for pointing out this bug in our documentation. This is still from Gurobi versions prior to 9.0, where an equality Q constraint would automatically lead to a "non-PSD" error (quadratic equat...

Yes. You really should take a look at the optimization status code in d.status. If it is GRB.INFEASIBLE, then the model is infeasible. If it is GRB.UNBOUNDED, then the model has an unbounded ray (b...

The KeyError is not from Gurobi. I guess this comes directly from Python and is triggered in the gurobipy module. Could it be that there is some j in M and i in N for which S[i,j] or v[j] does not ...

What is d.status? If it is GRB.INF_OR_UNBD or GRB.UNBOUNDED, then you won't be able to compute an IIS. You will only get an IIS for a provably infeasible model. If the status is GRB.INF_OR_UNBD, th...

When you have a minimization problem with optimal value 100, then at any point in time the incumbent objective value will be primalbound >= 100 while the objective bound will be dualbound <= 100 Wh...

Uhh... I fear that in this case you are out of luck. I doubt that we will want to increase the complexity of our parameter settings and combinations (that we have to document and also to test) for ...

A MIP start is a starting solution that is checked at the beginning of a solve whether it is feasible. If so, it will be used as an incumbent solution to speed up the optimization process. This MIP...