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Weaker constraint returns worse solution

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1 comment

  • Jaromił Najman
    Gurobi Staff Gurobi Staff

    Hi Gabriel and Lovisa,

    Just from looking at the Coefficient statistics of your model, it is very likely that the algorithm runs into numerical issues and can as a result provide contradicting results. We provide a lot of details about scaling and good model formulations in our Guidelines for Numerical Issues. You should definitely try playing with the NumericFocus parameter.

    the model returns a worse solution than when this constraint was tighter.

    Did you try writing out the solution to a sol file and providing it as MIP Start for the other formulation? You can write the solution from command line via the ResultFile parameter or via the write method if you are using gurobipy.

    Best regards, 


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