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Suboptimal solution returned as optimal in MIP

Awaiting user input

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2 comments

  • Sofia Perez-Guzman
    Gurobi-versary
    First Comment
    First Question

    Sending the log again: 

    Changed value of parameter NonConvex to 2

       Prev: -1  Min: -1  Max: 2  Default: -1

    Changed value of parameter DUAL_REDUCTIONS to 0

       Prev: 1  Min: 0  Max: 1  Default: 1

    Changed value of parameter InfUnbdInfo to 1

       Prev: 0  Min: 0  Max: 1  Default: 0

    Changed value of parameter FuncPieces to -1

       Prev: 0  Min: -2  Max: 200000000  Default: 0

    Changed value of parameter FuncPieceError to 0.01

       Prev: 0.001  Min: 1e-06  Max: 1000000.0  Default: 0.001

    Changed value of parameter FuncPieceRatio to 0.0

       Prev: -1.0  Min: -1.0  Max: 1.0  Default: -1.0

    Changed value of parameter MIPFocus to 2

       Prev: 0  Min: 0  Max: 3  Default: 0

    Changed value of parameter Presolve to 1

       Prev: -1  Min: -1  Max: 2  Default: -1

    No parameters matching 'IntFeasRol' found

    Changed value of parameter timeLimit to 100000.0

       Prev: inf  Min: 0.0  Max: inf  Default: inf

    Gurobi Optimizer version 9.0.2 build v9.0.2rc0 (win64)

    Optimize a model with 743 rows, 578 columns and 1591 nonzeros

    Model fingerprint: 0x57b0b44f

    Model has 170 quadratic constraints

    Model has 11 general constraints

    Variable types: 471 continuous, 107 integer (104 binary)

    Coefficient statistics:

      Matrix range     [1e-01, 1e+04]

      QMatrix range    [6e-02, 2e+00]

      QLMatrix range   [1e+00, 1e+04]

      Objective range  [1e+00, 1e+00]

      Bounds range     [1e-01, 1e+03]

      RHS range        [1e+00, 1e+04]

      QRHS range       [1e+00, 1e+04]

     

    Warning: Completing partial solution with 105 unfixed non-continuous variables out of 107

    User MIP start did not produce a new incumbent solution

     

    Presolve added 0 rows and 2037 columns

    Presolve removed 83 rows and 0 columns

    Presolve time: 0.04s

    Presolved: 1520 rows, 2851 columns, 9974 nonzeros

    Presolved model has 9 SOS constraint(s)

    Presolved model has 25 bilinear constraint(s)

    Variable types: 2753 continuous, 98 integer (96 binary)

     

    Root relaxation: objective 5.544015e+03, 346 iterations, 0.01 seconds

    Another try with MIP start

     

        Nodes    |    Current Node    |     Objective Bounds      |     Work

     Expl Unexpl |  Obj  Depth IntInf | Incumbent    BestBd   Gap | It/Node Time

     

         0     0 5544.01481    0   39          - 5544.01481      -     -    0s

         0     0 5688.79342    0   86          - 5688.79342      -     -    0s

         0     0 5806.27731    0   74          - 5806.27731      -     -    0s

         0     0 5813.89676    0   80          - 5813.89676      -     -    0s

         0     0 6034.03112    0   91          - 6034.03112      -     -    0s

         0     0 6065.66356    0   91          - 6065.66356      -     -    0s

         0     0 6237.90489    0   80          - 6237.90489      -     -    1s

         0     0 6241.68288    0   83          - 6241.68288      -     -    1s

         0     0 6309.42340    0   86          - 6309.42340      -     -    1s

         0     0 6315.98542    0   86          - 6315.98542      -     -    1s

         0     0 6390.46027    0   79          - 6390.46027      -     -    1s

         0     0 6396.00968    0   77          - 6396.00968      -     -    1s

         0     0 6466.54736    0   73          - 6466.54736      -     -    1s

         0     0 6475.12922    0   82          - 6475.12922      -     -    1s

         0     0 6530.18417    0   82          - 6530.18417      -     -    1s

         0     0 6537.74124    0   88          - 6537.74124      -     -    1s

         0     0 6551.85594    0   73          - 6551.85594      -     -    1s

         0     0 6560.48748    0   78          - 6560.48748      -     -    1s

         0     0 6597.61280    0   73          - 6597.61280      -     -    1s

         0     0 6599.37835    0   73          - 6599.37835      -     -    1s

         0     0 6608.22086    0   82          - 6608.22086      -     -    2s

         0     0 6609.10829    0   77          - 6609.10829      -     -    2s

         0     0 6626.15025    0   70          - 6626.15025      -     -    2s

         0     0 6628.36816    0   80          - 6628.36816      -     -    2s

         0     0 6698.97362    0   80          - 6698.97362      -     -    2s

         0     0 6705.50274    0   80          - 6705.50274      -     -    2s

         0     0 6718.12324    0   77          - 6718.12324      -     -    2s

         0     0 6728.21095    0   83          - 6728.21095      -     -    2s

         0     0 6738.24363    0   76          - 6738.24363      -     -    2s

         0     0 6743.84773    0   80          - 6743.84773      -     -    2s

         0     0 6773.61450    0   80          - 6773.61450      -     -    2s

         0     0 6774.91813    0   80          - 6774.91813      -     -    2s

         0     0 6784.04247    0   83          - 6784.04247      -     -    2s

         0     0 6784.04247    0   83          - 6784.04247      -     -    2s

         0     2 6784.04247    0   83          - 6784.04247      -     -    2s

      1034   686 14384.8076   18   60          - 9952.89104      -  12.9    5s

    * 2159   874              58    28894.280474 9952.89104  65.6%  13.4    5s

    H 2227   815                    28893.374778 9952.89104  65.6%  13.2    6s

    * 3285   929              47    25347.066269 10565.6386  58.3%  11.2    7s

    * 3521  1000              51    25346.516587 10648.6407  58.0%  11.1    7s

    * 3526   999              53    25346.337160 10648.6407  58.0%  11.0    7s

    * 3528   999              53    25346.298861 10648.6407  58.0%  11.0    7s

    * 5348  1498              54    24926.139783 10911.7472  56.2%   9.5    8s

    * 5349  1497              54    24925.519470 10911.7472  56.2%   9.5    8s

    * 7213  2073              60    24907.378887 11234.1390  54.9%   8.6    9s

    H 7492  1994                    23757.556933 11278.8271  52.5%   8.5    9s

      7519  2011 16863.7731   24   13 23757.5569 11278.8271  52.5%   8.5   10s

     14638  3436 infeasible   30      23757.5569 12512.1660  47.3%   7.4   15s

    *16564  3832              85    23530.904517 12885.1354  45.2%   7.3   16s

    *16565  3832              85    23530.902241 12885.1354  45.2%   7.3   16s

    *16566  3832              84    23530.899842 12885.1354  45.2%   7.3   16s

    *16567  3832              83    23530.897315 12885.1354  45.2%   7.3   16s

    *16568  3832              82    23530.894656 12885.1354  45.2%   7.3   16s

    *19009  4221              50    23355.730582 13155.9584  43.7%   7.1   17s

     22752  4817 14151.4527   26   13 23355.7306 13395.4596  42.6%   6.8   20s

     31189  5956 15755.0571   28   12 23355.7306 13816.8647  40.8%   6.5   25s

     40485  7190 21394.0706   32   16 23355.7306 14162.5339  39.4%   6.3   30s

    *40926  7135              62    23128.678047 14176.8797  38.7%   6.3   30s

    *43716  7479              64    23015.966057 14250.8943  38.1%   6.2   31s

    *45822  7737              72    23010.309911 14300.4162  37.9%   6.2   33s

    *49080  8129              67    23002.271049 14380.4729  37.5%   6.1   34s

     49710  8209 14445.2161   28   10 23002.2710 14391.9058  37.4%   6.1   35s

     58745  9285 15210.6247   29   14 23002.2710 14619.0750  36.4%   6.0   40s

    *68187 10219              66    22926.527633 14899.3675  35.0%   5.9   44s

     68866 10259 14997.1826   29   16 22926.5276 14918.7946  34.9%   5.9   45s

     77277 10867 infeasible   35      22926.5276 15192.8803  33.7%   5.9   50s

     86401 11756 18410.3639   28   16 22926.5276 15452.7230  32.6%   5.9   55s

    *91288 12115              64    22873.532433 15571.5403  31.9%   5.8   57s

     96403 12360 20703.0099   35   12 22873.5324 15732.2383  31.2%   5.8   60s

     105657 12886 17901.8325   27    8 22873.5324 15978.6237  30.1%   5.8   65s

     114004 13055 infeasible   28      22873.5324 16230.9210  29.0%   5.8   70s

     122315 13144 22303.9815   34    8 22873.5324 16468.0075  28.0%   5.8   75s

     129725 13193     cutoff   35      22873.5324 16665.1068  27.1%   5.9   80s

     137485 13301 21300.7452   35   13 22873.5324 16822.2013  26.5%   5.8   85s

     144871 13393     cutoff   27      22873.5324 16946.5411  25.9%   5.8   90s

     150906 13441 18762.5704   27   10 22873.5324 17064.7649  25.4%   5.8   95s

     157352 13389 17213.1779   27   13 22873.5324 17213.1779  24.7%   5.7  100s

     161692 13364 20000.8178   17   11 22873.5324 17331.5252  24.2%   5.7  105s

     168360 13281     cutoff   36      22873.5324 17496.9437  23.5%   5.7  110s

     173902 13115 infeasible   30      22873.5324 17635.6487  22.9%   5.7  115s

    *178803 12998              63    22871.197256 17731.9327  22.5%   5.7  118s

    *178807 12998              64    22871.197104 17731.9327  22.5%   5.7  118s

     180312 13017 infeasible   37      22871.1971 17763.5573  22.3%   5.7  120s

     186632 12986 17886.8643   28   10 22871.1971 17886.8643  21.8%   5.7  125s

     193006 12950 18008.2093   32   10 22871.1971 18008.2093  21.3%   5.6  130s

     199239 12732 20421.5142   30   13 22871.1971 18131.9273  20.7%   5.6  135s

     204380 12597 18245.1857   32   10 22871.1971 18245.1857  20.2%   5.6  140s

     210588 12468     cutoff   34      22871.1971 18393.1956  19.6%   5.6  145s

     215991 12265 20814.5248   28   10 22871.1971 18501.4464  19.1%   5.5  150s

     222037 12087 infeasible   34      22871.1971 18635.6635  18.5%   5.5  155s

     228245 11953 18743.5855   26    9 22871.1971 18743.5855  18.0%   5.5  160s

     233521 11739 19069.3630   31   14 22871.1971 18871.1331  17.5%   5.5  165s

     239766 11499     cutoff   29      22871.1971 19004.6010  16.9%   5.4  170s

     244786 11250 19097.2989   29   10 22871.1971 19097.2989  16.5%   5.4  175s

     250125 10960 infeasible   38      22871.1971 19215.5869  16.0%   5.4  180s

     255419 10716 infeasible   34      22871.1971 19339.0480  15.4%   5.4  185s

     260571 10402     cutoff   26      22871.1971 19446.9218  15.0%   5.3  190s

     265421 10106 19551.4153   29   10 22871.1971 19551.4153  14.5%   5.3  195s

     269835  9767 19671.9962   29   13 22871.1971 19671.9962  14.0%   5.3  200s

     274187  9375 19845.8157   29   12 22871.1971 19781.3743  13.5%   5.3  205s

     278535  9013 20194.8078   19   13 22871.1971 19885.3520  13.1%   5.3  210s

     283848  8577     cutoff   32      22871.1971 19997.5115  12.6%   5.3  215s

     288397  7997 21257.5445   34   12 22871.1971 20173.5093  11.8%   5.3  220s

     291948  7336 infeasible   24      22871.1971 20342.2819  11.1%   5.3  225s

     295624  6691 infeasible   34      22871.1971 20541.0609  10.2%   5.3  230s

    *296408  6527              69    22856.454879 20575.6517  10.0%   5.3  231s

    *296410  6527              70    22856.454853 20575.6517  10.0%   5.3  231s

     298664  6030 21162.3697   30   10 22856.4549 20694.0302  9.46%   5.3  235s

     301722  5285 infeasible   27      22856.4549 20877.5152  8.66%   5.3  240s

     305531  4375 infeasible   31      22856.4549 21139.2608  7.51%   5.3  245s

     308661  3681 infeasible   36      22856.4549 21380.9499  6.46%   5.3  250s

     311837  2865     cutoff   30      22856.4549 21652.3544  5.27%   5.3  255s

     315652  1985 22497.4404   44   12 22856.4549 22017.4032  3.67%   5.3  261s

     318672  1400 22530.0737   42   13 22856.4549 22294.9389  2.46%   5.3  265s

    *321943   972              66    22856.369995 22549.5557  1.34%   5.3  268s

    *322528   943              72    22855.884193 22591.0019  1.16%   5.3  269s

    *322529   943              72    22855.864959 22591.0019  1.16%   5.3  269s

     323250   876 22633.6560   44   16 22855.8650 22632.5928  0.98%   5.3  270s

    *327034   436              75    22855.168540 22790.6060  0.28%   5.2  274s

    *327044   432              79    22855.050942 22790.6060  0.28%   5.2  274s

    *327045   432              79    22855.044936 22790.6060  0.28%   5.2  274s

    *327046   430              78    22855.038619 22790.6060  0.28%   5.2  274s

     328824   230     cutoff   56      22855.0386 22839.8348  0.07%   5.2  275s

    *328922   230              77    22855.034849 22839.8348  0.07%   5.2  275s

    *328924   230              75    22855.009242 22839.8348  0.07%   5.2  275s

    *330323   203              80    22854.957680 22848.6399  0.03%   5.2  276s

    *330327   203              82    22854.957672 22848.6399  0.03%   5.2  276s

    *330329   203              83    22854.957666 22848.6399  0.03%   5.2  276s

    *330342   203              90    22854.957133 22848.6399  0.03%   5.2  276s

     

    Cutting planes:

      Gomory: 9

      Cover: 25

      Implied bound: 99

      Projected implied bound: 2

      Clique: 7

      MIR: 14

      Flow cover: 95

      RLT: 37

      Relax-and-lift: 26

      BQP: 2

     

    Explored 331712 nodes (1727866 simplex iterations) in 277.19 seconds

    Thread count was 8 (of 8 available processors)

     

    Solution count 10: 22855 22855 22855 ... 22855.2

     

    Optimal solution found (tolerance 1.00e-04)

    Warning: max constraint violation (2.9212e-03) exceeds tolerance

    Warning: max general constraint violation (2.9212e-03) exceeds tolerance

             (model may be infeasible or unbounded - try turning presolve off)

    Best objective 2.285495713262e+04, best bound 2.285462660876e+04, gap 0.0014%

     

    0
  • Jaromił Najman
    Gurobi Staff Gurobi Staff

    Hi Sofia,

    Please note that your code is not reproducible because values for parameters \(\texttt{mobil, populations, epoch_e, epoch_l, pods, dcs, sub_e2, ...}\) are missing.

    The final solution is not feasible because it has a high constraint and general constraint violation

    Warning: max constraint violation (2.9212e-03) exceeds tolerance
    Warning: max general constraint violation (2.9212e-03) exceeds tolerance
    (model may be infeasible or unbounded - try turning presolve off)

    There are multiple things you might want to try to avoid this. You should try updating to the latest version of Gurobi. You are setting the FuncPieceError parameter to a quite high value. In order to increase accuracy you should rather decrease this value. In general, I would recommend experimenting with the FuncPieces value instead of the FuncPieceError parameter. Note that increasing the value of FuncPieces also increases the size of the model and may hurt performance (this always holds when playing with tolerances). I am not sure whether you really need the FuncPieceRatio parameter, I would just leave it at default. Then, I would recommend strictly bounding all variables participating in general constraints (both \(x\) and \(y\) variables), e.g., variables \(\texttt{auxX}\) should all have a tight upper bound. We discuss tackling numerical issues and constraint violations in our Guidelines for Numerical Issues.

    In case that your model is declared infeasible, the article How do I determine why my model is infeasible? should be of interest.

    Best regards, 
    Jaromił

    0

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