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How to get the fractional values of the root node relaxation solution?

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  • 正式なコメント
    Simranjit Kaur
    • Gurobi Staff Gurobi Staff
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  • Jaromił Najman
    • Gurobi Staff Gurobi Staff

    Hi Farin,

    Could you post the LOG of your optimization run and/or some output showing the behavior? Are you sure that you are in the MIPNODE callback? Please note that if the relaxation solution is integral, no MIPNODE will be performed, since we can directly terminate the optimization process.

    Best regards,
    Jaromił

    0
  • Farin Rastgar Amini
    • Gurobi-versary
    • First Comment
    • First Question

    Hi Jaromil,

    Thank you for the feedback. It seems that the relaxation solution is not integral. Here is the LOG from the moment after sifting:

    Root relaxation: objective 5.247974e+04, 508821 iterations, 204.58 seconds 
    Total elapsed time = 645.08s
    Total elapsed time = 681.20s Total elapsed time = 728.88s
    Total elapsed time = 766.43s
    Nodes | Current Node | Objective Bounds | Work Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time
    0 0 52479.7442 0 72 - 52479.7442 - - 811s
    []
    0 0 52500.1714 0 301 - 52500.1714 - - 916s
    []
    0 0 52598.8421 0 290 - 52598.8421 - - 1045s
    []
    0 0 52620.0000 0 178 - 52620.0000 - - 1144s
    []
    0 0 52620.0000 0 181 - 52620.0000 - - 1157s
    []
    0 0 52620.0000 0 200 - 52620.0000 - - 1208s
    []
    * 0 0 0 52620.000000 52620.0000 0.00% - 1344s
    Cutting planes:
    Cover: 1
    Clique: 10
    MIR: 5
    StrongCG: 6
    GUB
    cover: 26
    Zero half: 4
    Relax-and-lift: 4
    Explored 1 nodes (783910 simplex iterations) in 1345.40 seconds Thread count was 1 (of 8 available processors) Solution count 1: 52620 Optimal solution found (tolerance 1.00e-04) Best objective 5.262000000000e+04, best bound 5.262000000000e+04, gap 0.0000% User-callback calls 16806, time in user-callback 1.46 sec
    0

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