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Slow MIPS Performance

Ongoing

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  • Official comment
    Simranjit Kaur
    Gurobi Staff Gurobi Staff
    This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.
  • Matthias Miltenberger
    Gurobi Staff Gurobi Staff

    Hi Animesh,

    What makes you think that this is "poor" performance? Just because a model isn't huge doesn't mean that it is easy to solve. From the log, you can see that Gurobi is making steady progress to close the gap after quickly finding a good solution. Often, proving optimality is pretty tough and can result in a large tree even if the optimal solution has been found early.

    For an extreme example, I can recommend the MIPLIB 2017 instance ej. This instance only has 3 variables and one constraint and if you don't solve it in presolving (with Gurobi you need to set Presolving=0), you will build up a very huge tree with very slow progress.

    You might want to look into your model to improve its formulation. Maybe you can find a different way to express the underlying problem and to tighten the LP relaxation.

    Cheers,
    Matthias

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