Mario Ruthmair

Hi JC, In which sense does it not scale? Is the runtime not reasonable anymore for larger instances? Of course, if you have cycles of odd length in your graph, then the problem is infeasible. But y...

Hi JC, Ok, now I got it. This might be related to the graph-theoretical concept of an independent (or stable) set. The term "circle" puzzled me, actually you mean a vertex or a node in a graph. You...

Hi JC, Sorry, but it is impossible for me to understand the actual optimization problem. Could you please be a bit more detailed, probably by providing a formal problem description? Best regards,Mario

Hi Luca! If you are not experienced with callbacks, I would suggest to start with an easier modeling approach to eliminate subtours without need for callbacks, e.g., by using Big-M constraints with...

Hi Ashrafur, The lower and upper bounds to variable L(r,i) are basically defined by constants (vehicle capacity Q(r) and customer demand q(i)), right? So the min and max operators can be applied in...

Hi Dilip, Yes, this looks correct. Mario

Hi Dilip, Did you try it and analyze the solutions? 2nd model: I do not think that it works since you just added a single constraint, instead of one constraint for each vehicle k. 12 days ago you a...

Hi Dilip, We already discussed how you can model a min-max objective function, see the messages above. So, could you be a bit more precise about what does not work with the approach I suggested? Be...

Hi Dilip, I am not sure if I can follow your last messages. Do you still have problems? Best regards,Mario

Hi Lorenzo, We had a discussion with our developers and the following is the answer my colleague Silke already told your colleague Luca. I just add it here for completeness: "The exception is ignor...