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gurobi struggles to narrow the gap of MIP

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4 comments

  • Riley Clement
    Gurobi Staff Gurobi Staff

    Hi Suyue,

    This is certainly not unusual.  Perhaps consider experimenting with MIPFocus and Cuts parameters to try and focus on improving the lower bound?  Since you have a large B&B tree perhaps try different BranchDir values, although it's not likely to help.

    - Riley

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  • Suyue Xu
    Curious
    Gurobi-versary
    Conversationalist

    Hi Riley

    I've tried to experiment with MIPFocus and Cuts to set them to 3,and try different branch direction,but all these measures make no difference.What do you mean by "improving the lower bound", say improving the lower bound of matrix range?

    Thanks in advance!

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  • Riley Clement
    Gurobi Staff Gurobi Staff

    Hi Suyue,

    The "lower bound" here refers to the BestBd value in the node log.  In this case "lower" because this is a minimization problem.  It seems to be steadily improving so it would be nice if it improved a little faster.

    You could always try our Parameter Tuning Tool - perhaps tuning for MIP gap with a 10 minute time limit.

    - Riley

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  • Suyue Xu
    Curious
    Gurobi-versary
    Conversationalist

    Thank you for your advice!

    0

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