• Gurobi Staff

Hi Mike,

Could you try setting the parameter StartNodeLimit to -2? Does this resolve the issue?

Best regards,
Jaromił

Hi Jaromil,

thanks a lot for the answer! It did improve the performance. However, I opted now to simply retreive solution from .sol files that I generate with an easy to solve version of the model.

Related to .sol files, is there a way to query .sol files and select the one as a MIP start that has the best objective value, i.e. the best starting solution?

Thank you and best regards,

Mike

As a follow-up question: When I start from a .sol file I still get the message that the MIP start did not produce a new incumbent solution.

This also happens if I generate the .sol file from the same identical model where I want to use the MIP start. Just for checking the process this should work. However, even though simply generate files with

model.setParam('SolFiles', myPath)

model.read(myPath)

I still get

User MIP start did not produce a new incumbent solution

is there a reasonable explanation, something that I might be missing?

Thank you very much!

• Gurobi Staff

Hi Mike,

You can provide multiple SOL files via the InputFile parameter if you are running from command line, e.g.,

>gurobi_cl InputFile=sol1.sol InputFile=sol2.sol myModel.lp

Setting multiple initial points is explained in the documentation of the Start parameter.

Best regards,
Jaromił

• Gurobi Staff

I don't see a proper explanation for the behavior you describe. Could you provide a minimal working example?

Hi Jaromil,

In the meantime I fixed the issue, I believe it was somehow related to my callback procedure.