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how much does solution pool completion proceeds

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6 comments

  • Tobias Achterberg
    Gurobi Staff Gurobi Staff

    Seeing the progress is not so easy when completing the solution pool. Obviously, the gap doesn't give you any indication anymore. The only relevant statistics that you can look at are the number of open nodes. In your case, this grew up to about 11400 nodes and seems to stay in this range. So, there is not yet any sign of getting done.

    You could install a callback and query the MIP_SOLCNT value to know how many solutions are already in the pool. But if you don't know how many solutions exist for your model, this value won't be very useful either in assessing the progress.

    Regards,

    Tobias

    1
  • Elisabeth Rodríguez Heck
    Gurobi Staff Gurobi Staff

    Hi Akram,

    To find more feasible solutions, in addition to setting the PoolSolutions parameter, you should also set the PoolSearchMode parameter to one of the non-default values. 

    You can find more information on this topic in the Finding Multiple Solutions documentation section. 

    Best regards,

    Elisabeth

    0
  • Akram Kh
    Gurobi-versary
    Conversationalist
    Curious

    Dear Elisabeth,

    Thanks for your reply. I have read those parts and set the corresponding parameters. It seems that is working correct. However, I cannot find that how much has it proceeded (by the Gurobi log)!

    Regards,

    Akram

    0
  • Elisabeth Rodríguez Heck
    Gurobi Staff Gurobi Staff

    Hi Akram,

    The documentation page Solution Pool and Multi-Scenario Logging explains what you should see in the Gurobi log in the second phase (once attention has shifted towards finding solutions beyond that one optimal solution). 

    If this doesn't answer your question, could you share the logfile that you are analyzing?

    Best regards,

    Elisabeth

    0
  • Akram Kh
    Gurobi-versary
    Conversationalist
    Curious

    Hi Elisabeth,

    I heve set the parameters as follows:

    PoolSolutions=2000000000 (max possible value)

    PoolSearchMode=2

    and here is some part of the gurobi log (if it helps):

    Root relaxation: objective 3.000000e+00, 1 iterations, 0.00 seconds

    Nodes | Current Node | Objective Bounds | Work
    Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time

    * 0 0 0 3.0000000 3.00000 0.00% - 0s

    Optimal solution found at node 0 - now completing solution pool...

    Nodes | Current Node | Pool Obj. Bounds | Work
    | | Worst |
    Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time

    0 0 - 0 - 3.00000 - - 0s
    0 0 - 0 - 3.00000 - - 0s
    0 2 - 0 - 3.00000 - - 0s
    72883 5972 cutoff 138 - 3.00000 - 0.0 7s
    88899 6362 - 135 - 3.00000 - 0.0 10s
    120931 6886 cutoff 138 - 3.00000 - 0.0 19s
    136947 7186 - 137 - 3.00000 - 0.0 26s
    152963 7400 - 137 - 3.00000 - 0.0 33s
    168979 7656 cutoff 138 - 3.00000 - 0.0 41s
    184995 7956 cutoff 138 - 3.00000 - 0.0 52s
    201011 8202 cutoff 138 - 3.00000 - 0.0 63s
    217027 8380 - 134 - 3.00000 - 0.0 76s
    233043 8886 - 137 - 3.00000 - 0.0 90s
    249059 9038 cutoff 138 - 3.00000 - 0.0 106s
    265075 9290 - 137 - 3.00000 - 0.0 123s
    281091 9454 - 136 - 3.00000 - 0.0 141s
    297107 9622 cutoff 138 - 3.00000 - 0.0 160s
    313123 9760 - 135 - 3.00000 - 0.0 181s
    329139 9936 - 131 - 3.00000 - 0.0 203s
    345155 10170 - 136 - 3.00000 - 0.0 227s
    361171 10288 - 137 - 3.00000 - 0.0 252s
    377187 10356 cutoff 138 - 3.00000 - 0.0 279s
    393203 10472 cutoff 138 - 3.00000 - 0.0 308s
    409219 10626 cutoff 138 - 3.00000 - 0.0 338s
    425235 10718 cutoff 138 - 3.00000 - 0.0 370s
    441251 10796 - 136 - 3.00000 - 0.0 403s
    457267 10868 cutoff 138 - 3.00000 - 0.0 437s
    473283 10940 cutoff 138 - 3.00000 - 0.0 474s
    489299 11024 cutoff 138 - 3.00000 - 0.0 510s
    505315 11082 cutoff 138 - 3.00000 - 0.0 548s
    521331 11116 cutoff 138 - 3.00000 - 0.0 587s
    537347 11118 cutoff 138 - 3.00000 - 0.0 627s
    553363 11138 cutoff 138 - 3.00000 - 0.0 669s
    569379 11176 cutoff 138 - 3.00000 - 0.0 712s
    585395 11236 cutoff 138 - 3.00000 - 0.0 757s
    601411 11312 - 137 - 3.00000 - 0.0 803s
    617427 11302 - 137 - 3.00000 - 0.0 852s
    633443 11336 cutoff 138 - 3.00000 - 0.0 902s
    649459 11354 - 136 - 3.00000 - 0.0 955s
    665475 11354 - 137 - 3.00000 - 0.0 1009s
    681491 11376 cutoff 138 - 3.00000 - 0.0 1064s
    697507 11402 cutoff 138 - 3.00000 - 0.0 1122s
    713523 11436 - 137 - 3.00000 - 0.0 1180s
    729539 11480 cutoff 138 - 3.00000 - 0.0 1239s
    745555 11448 - 137 - 3.00000 - 0.0 1299s
    761571 11446 - 137 - 3.00000 - 0.0 1361s
    777587 11412 - 137 - 3.00000 - 0.0 1424s
    793603 11338 - 136 - 3.00000 - 0.0 1490s
    809619 11324 - 133 - 3.00000 - 0.0 1562s
    825635 11294 cutoff 138 - 3.00000 - 0.0 1634s
    841651 11294 cutoff 138 - 3.00000 - 0.0 1708s
    857667 11264 - 136 - 3.00000 - 0.0 1783s
    873683 11292 cutoff 138 - 3.00000 - 0.0 1860s
    889699 11282 cutoff 138 - 3.00000 - 0.0 1937s
    905715 11278 - 137 - 3.00000 - 0.0 2017s
    921731 11260 cutoff 138 - 3.00000 - 0.0 2098s
    937747 11274 cutoff 138 - 3.00000 - 0.0 2180s
    953763 11238 - 135 - 3.00000 - 0.0 2263s
    969779 11252 - 136 - 3.00000 - 0.0 2347s
    985795 11294 cutoff 138 - 3.00000 - 0.0 2433s
    1001811 11294 - 130 - 3.00000 - 0.0 2521s
    1017827 11284 - 137 - 3.00000 - 0.0 2610s
    1033843 11250 cutoff 138 - 3.00000 - 0.0 2700s
    1049859 11226 - 137 - 3.00000 - 0.0 2790s
    1065875 11244 cutoff 138 - 3.00000 - 0.0 2882s
    1081891 11200 - 132 - 3.00000 - 0.0 2975s
    1097907 11188 cutoff 138 - 3.00000 - 0.0 3070s
    1113923 11130 cutoff 138 - 3.00000 - 0.0 3166s
    1129939 11128 - 137 - 3.00000 - 0.0 3264s
    1145955 11104 cutoff 138 - 3.00000 - 0.0 3363s
    1161971 11082 cutoff 138 - 3.00000 - 0.0 3464s
    1177987 11098 - 137 - 3.00000 - 0.0 3566s
    1194003 11076 - 134 - 3.00000 - 0.0 3673s
    1210019 11060 cutoff 138 - 3.00000 - 0.0 3782s
    1226035 11052 cutoff 138 - 3.00000 - 0.0 3892s
    1242051 11078 - 134 - 3.00000 - 0.0 4001s
    1258067 11052 cutoff 138 - 3.00000 - 0.0 4112s
    1274083 11006 - 136 - 3.00000 - 0.0 4230s
    1290099 11064 - 137 - 3.00000 - 0.0 4350s
    1306115 11108 - 137 - 3.00000 - 0.0 4471s
    1322131 11122 cutoff 138 - 3.00000 - 0.0 4591s
    1338147 11176 - 137 - 3.00000 - 0.0 4713s
    1354163 11174 - 136 - 3.00000 - 0.0 4835s
    1370179 11262 cutoff 138 - 3.00000 - 0.0 4956s
    1386195 11254 cutoff 138 - 3.00000 - 0.0 5079s
    1402211 11218 - 134 - 3.00000 - 0.0 5204s
    1418227 11256 cutoff 138 - 3.00000 - 0.0 5330s

    .

    .

    .

    -----------------------------------------------------------------------------------

    Do you know how can I understand how is the solution pool completion proceeding?

     

    0
  • Akram Kh
    Gurobi-versary
    Conversationalist
    Curious

    Dear Tobias,

    Thanks for your reply. That was a great guide for me!

    Best regards,

    Akram

    0

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