Got different results for the same case in two different platforms.

Comments

3 comments

  • Thomas Opfer

    The documentation says:

    • The MIP solver will terminate (with an optimal result) when the gap between the lower and upper objective bound is less than MIPGap times the absolute value of the upper bound.
    • The MIP solver will terminate (with an optimal result) when the gap between the lower and upper objective bound is less than MIPGapAbs.

    While I am not sure, I think it is sufficient if one of these criteria is fulfilled.

    Of course, it can happen that the solver has different solutions on different platforms. Still, if you set both gaps to zero (and if there are no other termination criteria), you should get the same objective value (if no numerical problems are present).

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  • Sonja Mars

    Hi,

    Yes, Thomas is correct, the solver will stop if one termination criterion is fulfilled.

     

    The same is true if you for example set a time limit to 100 seconds and a MIP gap of 1%. It the solver reaches 1% after 60 seconds it will stop, and if the solver still has 5% gap after 100 seconds it will also stop.

    Best regards,

      Sonja

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  • Greg Glockner

    You may also want to see this knowledge base article: "Is Gurobi Optimizer deterministic". (Sorry it wasn't visible when you wrote your post).

     

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