Heuristic not used
回答済みHi there,
I'm using Gurobi to solve a very large problem that may take a few days. However, I observed that in the first 48 hours no heuristic was used, and no feasible solution had been founded so far, which is very different compared to the solving process when I run the same model with smaller sampling data: I usually see the heuristic finds a feasible solution before it reaches the nodes.
Could anyone help to clarify if this is normal and why the heuristic hasn't been used?
I've attached the current log below. Thanks in advance!
Set parameter Cuts to value 2
Set parameter NodefileStart to value 0.5
Gurobi Optimizer version 9.5.1 build v9.5.1rc2 (win64)
Thread count: 8 physical cores, 16 logical processors, using up to 16 threads
Optimize a model with 1824708 rows, 1005265 columns and 15981149 nonzeros
Model fingerprint: 0xa8153788
Model has 3695 quadratic constraints
Variable types: 144 continuous, 1005121 integer (1005108 binary)
Coefficient statistics:
Matrix range [8e-04, 1e+03]
QMatrix range [1e+00, 1e+02]
QLMatrix range [1e+02, 1e+02]
Objective range [1e-01, 1e+02]
Bounds range [1e+00, 1e+00]
RHS range [1e+00, 6e+02]
Presolve removed 1058140 rows and 475310 columns (presolve time = 5s) ...
Presolve removed 1061835 rows and 475310 columns (presolve time = 10s) ...
Presolve removed 1061844 rows and 500747 columns (presolve time = 15s) ...
Presolve removed 1061844 rows and 500747 columns (presolve time = 20s) ...
Presolve removed 1061844 rows and 500747 columns (presolve time = 25s) ...
Presolve removed 1061844 rows and 500747 columns (presolve time = 131s) ...
Presolve removed 1062255 rows and 500902 columns (presolve time = 136s) ...
Presolve removed 1062738 rows and 500902 columns (presolve time = 140s) ...
Presolve removed 1062680 rows and 500844 columns
Presolve time: 142.74s
Presolved: 991614 rows, 730312 columns, 11719844 nonzeros
Variable types: 0 continuous, 730312 integer (504333 binary)
Deterministic concurrent LP optimizer: primal simplex, dual simplex, and barrier
Showing barrier log only...
Root barrier log...
Ordering time: 0.98s
Barrier statistics:
Dense cols : 127
AA' NZ : 3.786e+07
Factor NZ : 9.006e+07 (roughly 1.4 GB of memory)
Factor Ops : 1.334e+10 (less than 1 second per iteration)
Threads : 5
Objective Residual
Iter Primal Dual Primal Dual Compl Time
0 1.50485942e+09 -4.15867733e+10 3.23e+08 1.02e+00 4.04e+06 290s
1 1.19830511e+09 -4.17309479e+10 2.56e+08 1.70e+02 3.09e+06 291s
2 1.07256987e+09 -4.08778766e+10 2.30e+08 5.00e+01 2.47e+06 293s
3 8.74455611e+08 -4.53369735e+10 1.87e+08 3.70e-02 2.04e+06 295s
4 3.25789923e+07 -4.14061399e+10 6.97e+06 2.76e+00 9.19e+04 298s
5 9.84091972e+06 -2.12371202e+10 2.09e+06 5.28e-01 2.95e+04 300s
6 5.22386157e+06 -1.72532428e+10 1.10e+06 4.28e-01 1.78e+04 302s
7 1.54028072e+06 -6.02619147e+09 3.17e+05 1.05e-01 5.29e+03 303s
8 9.36368013e+05 -2.81314574e+09 1.90e+05 3.85e-02 2.66e+03 305s
9 8.14588222e+05 -1.78586345e+09 1.65e+05 2.10e-02 1.91e+03 307s
10 4.18523274e+05 -1.29901126e+09 7.50e+04 1.20e-02 1.03e+03 310s
11 1.21828807e+05 -4.83240402e+08 5.99e+03 3.66e-03 2.31e+02 312s
12 1.18493689e+05 -7.96578017e+07 5.22e+03 5.08e-04 5.19e+01 314s
13 9.88301629e+04 -6.55288211e+07 4.57e+02 4.51e-04 2.87e+01 316s
14 9.76323957e+04 -1.35567046e+07 5.06e+01 7.84e-05 5.77e+00 318s
15 9.24001834e+04 -1.30235761e+06 3.02e+00 5.01e-06 5.81e-01 320s
16 8.40776217e+04 -7.55528020e+05 2.21e+00 7.60e-08 3.51e-01 322s
17 8.08773490e+04 -6.22033572e+05 1.82e+00 8.00e-08 2.94e-01 324s
18 6.89440479e+04 -4.29632411e+05 1.10e+00 3.53e-06 2.08e-01 326s
19 5.73108326e+04 -3.18883569e+05 7.34e-01 7.98e-06 1.57e-01 328s
20 5.74810537e+04 -2.90134730e+05 7.19e-01 1.06e-05 1.45e-01 330s
21 5.15323849e+04 -2.13479045e+05 5.83e-01 1.36e-07 1.11e-01 333s
22 5.15292122e+04 -2.04744590e+05 5.61e-01 1.25e-07 1.07e-01 335s
23 4.60451763e+04 -1.69475801e+05 4.32e-01 1.07e-07 9.00e-02 338s
24 3.63850541e+04 -1.36802039e+05 2.64e-01 8.45e-08 7.21e-02 340s
25 3.19302747e+04 -1.01280743e+05 2.13e-01 6.94e-08 5.55e-02 343s
26 2.99608766e+04 -8.72371960e+04 1.87e-01 7.09e-08 4.89e-02 345s
27 2.49219486e+04 -7.36488793e+04 1.33e-01 6.74e-08 4.10e-02 348s
28 2.31240789e+04 -5.89245062e+04 1.16e-01 6.60e-08 3.42e-02 350s
29 2.23642240e+04 -5.43912416e+04 1.07e-01 7.07e-08 3.20e-02 352s
30 2.01357748e+04 -4.81535017e+04 8.57e-02 6.45e-08 2.84e-02 355s
31 1.84911097e+04 -4.01942609e+04 7.15e-02 2.40e-07 2.44e-02 357s
32 1.64842510e+04 -3.07261448e+04 5.55e-02 5.23e-06 1.97e-02 360s
33 1.54666701e+04 -2.20083634e+04 4.85e-02 4.57e-06 1.56e-02 362s 34 1.30461575e+04 -1.74935842e+04 3.15e-02 6.37e-06 1.27e-02 365s 35 1.24057436e+04 -1.27371787e+04 2.75e-02 2.82e-06 1.05e-02 367s 36 1.12469125e+04 -9.23135215e+03 2.05e-02 4.70e-06 8.53e-03 370s 37 1.06670622e+04 -6.96399832e+03 1.72e-02 3.60e-06 7.34e-03 372s 38 1.02019752e+04 -5.85088235e+03 1.46e-02 3.86e-06 6.68e-03 374s 39 9.90610673e+03 -5.25676969e+03 1.29e-02 3.06e-06 6.31e-03 377s 40 9.64019472e+03 -4.33268473e+03 1.14e-02 2.43e-06 5.81e-03 379s 41 9.29531928e+03 -3.18082472e+03 9.47e-03 2.72e-06 5.19e-03 382s 42 9.15824686e+03 -1.67326448e+03 8.69e-03 2.26e-06 4.51e-03 385s 43 9.02072435e+03 -1.13949385e+03 7.96e-03 3.11e-06 4.23e-03 387s 44 8.93070987e+03 6.09569859e+01 7.48e-03 1.44e-06 3.69e-03 390s 45 8.78850110e+03 6.08977467e+02 6.74e-03 2.62e-06 3.40e-03 392s 46 8.59718034e+03 1.43207806e+03 5.75e-03 2.59e-07 2.98e-03 395s 47 8.45549533e+03 2.16440419e+03 5.03e-03 1.98e-08 2.62e-03 397s 48 8.32756885e+03 2.57024578e+03 4.40e-03 1.71e-08 2.40e-03 400s 49 8.26623890e+03 3.51586955e+03 4.09e-03 1.86e-07 1.98e-03 402s 50 8.17373140e+03 3.75069777e+03 3.64e-03 9.07e-07 1.84e-03 405s 51 8.13409941e+03 3.83802643e+03 3.45e-03 4.52e-07 1.79e-03 407s 52 8.06694708e+03 4.00300605e+03 3.13e-03 4.53e-07 1.69e-03 409s 53 8.03210306e+03 4.18412107e+03 2.97e-03 6.06e-07 1.60e-03 412s 54 7.97550837e+03 4.42089631e+03 2.71e-03 2.78e-06 1.48e-03 414s 55 7.91080398e+03 4.65473669e+03 2.41e-03 3.10e-06 1.36e-03 417s 56 7.88527727e+03 4.90663217e+03 2.29e-03 1.80e-06 1.24e-03 420s 57 7.86517949e+03 4.98146708e+03 2.19e-03 1.65e-06 1.20e-03 422s 58 7.82630430e+03 5.19908123e+03 2.01e-03 2.82e-06 1.09e-03 425s 59 7.79243450e+03 5.32467570e+03 1.86e-03 2.74e-06 1.03e-03 428s 60 7.75958946e+03 5.48786340e+03 1.72e-03 4.49e-06 9.46e-04 431s 61 7.72447435e+03 5.62863558e+03 1.58e-03 5.58e-06 8.72e-04 434s 62 7.69914095e+03 5.73272846e+03 1.47e-03 4.87e-06 8.19e-04 438s 63 7.68803182e+03 5.75871477e+03 1.43e-03 5.11e-06 8.03e-04 441s 64 7.67217983e+03 5.77311884e+03 1.36e-03 5.11e-06 7.90e-04 445s 65 7.64933032e+03 5.88422029e+03 1.27e-03 5.35e-06 7.34e-04 448s 66 7.63509085e+03 5.92871019e+03 1.21e-03 4.73e-06 7.10e-04 452s 67 7.61968483e+03 5.99323349e+03 1.15e-03 4.34e-06 6.77e-04 455s 68 7.60484194e+03 6.06413455e+03 1.09e-03 4.51e-06 6.41e-04 459s 69 7.58415072e+03 6.13259789e+03 1.01e-03 4.76e-06 6.04e-04 463s 70 7.56830595e+03 6.15066103e+03 9.47e-04 4.69e-06 5.89e-04 467s 71 7.55473692e+03 6.19392845e+03 8.95e-04 4.46e-06 5.66e-04 471s 72 7.54305954e+03 6.28411920e+03 8.53e-04 4.98e-06 5.24e-04 475s 73 7.52414483e+03 6.31598529e+03 7.80e-04 4.84e-06 5.02e-04 479s 74 7.51590201e+03 6.37078430e+03 7.48e-04 3.93e-06 4.76e-04 483s 75 7.50521984e+03 6.42065090e+03 7.06e-04 3.13e-06 4.51e-04 487s 76 7.49169961e+03 6.46643244e+03 6.54e-04 2.77e-06 4.26e-04 491s 77 7.48630790e+03 6.50887848e+03 6.35e-04 2.88e-06 4.06e-04 495s 78 7.48056440e+03 6.54212408e+03 6.15e-04 2.41e-06 3.90e-04 499s 79 7.47212150e+03 6.56097458e+03 5.85e-04 2.20e-06 3.79e-04 503s 80 7.46355803e+03 6.58987152e+03 5.53e-04 2.37e-06 3.63e-04 507s 81 7.45867451e+03 6.60533205e+03 5.36e-04 2.65e-06 3.55e-04 511s 82 7.45128685e+03 6.63376840e+03 5.09e-04 2.26e-06 3.40e-04 514s 83 7.44503579e+03 6.66649892e+03 4.89e-04 1.32e-06 3.24e-04 519s 84 7.43749265e+03 6.68141027e+03 4.66e-04 1.57e-06 3.14e-04 523s 85 7.43085517e+03 6.70779523e+03 4.43e-04 1.11e-06 3.00e-04 527s
86 7.42582619e+03 6.72667470e+03 4.26e-04 8.90e-07 2.90e-04 531s 87 7.41775091e+03 6.75880688e+03 4.02e-04 1.61e-06 2.74e-04 536s 88 7.41097657e+03 6.79237769e+03 3.83e-04 2.08e-06 2.57e-04 540s 89 7.40601577e+03 6.81059776e+03 3.69e-04 2.15e-06 2.47e-04 544s 90 7.40084629e+03 6.83832147e+03 3.55e-04 1.69e-06 2.34e-04 548s 91 7.39201684e+03 6.86443646e+03 3.31e-04 1.26e-06 2.19e-04 553s 92 7.38612129e+03 6.88337938e+03 3.15e-04 1.10e-06 2.09e-04 557s 93 7.38133815e+03 6.91351980e+03 3.02e-04 1.43e-06 1.94e-04 562s 94 7.37493596e+03 6.93146194e+03 2.84e-04 1.23e-06 1.84e-04 566s 95 7.37409374e+03 6.95167272e+03 2.82e-04 1.47e-06 1.76e-04 571s 96 7.36937544e+03 6.96015410e+03 2.69e-04 1.45e-06 1.70e-04 575s 97 7.36477621e+03 6.97039283e+03 2.58e-04 1.39e-06 1.64e-04 580s 98 7.36027995e+03 6.98478579e+03 2.47e-04 9.78e-07 1.56e-04 584s 99 7.35466872e+03 6.99216462e+03 2.33e-04 1.13e-06 1.51e-04 588s 100 7.35277054e+03 7.00412950e+03 2.29e-04 1.27e-06 1.45e-04 591s 101 7.34753709e+03 7.01729118e+03 2.15e-04 1.72e-06 1.37e-04 596s 102 7.34300008e+03 7.02593015e+03 2.04e-04 1.87e-06 1.32e-04 600s 103 7.33918474e+03 7.03864881e+03 1.94e-04 1.33e-06 1.25e-04 604s 104 7.33702207e+03 7.04455228e+03 1.88e-04 1.40e-06 1.22e-04 608s 105 7.33346752e+03 7.05713977e+03 1.78e-04 1.14e-06 1.15e-04 612s 106 7.32997401e+03 7.07412217e+03 1.70e-04 1.19e-06 1.06e-04 616s 107 7.32773579e+03 7.07959319e+03 1.64e-04 1.26e-06 1.03e-04 620s 108 7.32479578e+03 7.08684500e+03 1.56e-04 1.03e-06 9.90e-05 624s 109 7.32273930e+03 7.09608658e+03 1.51e-04 1.33e-06 9.43e-05 628s 110 7.32027759e+03 7.10238201e+03 1.45e-04 1.51e-06 9.06e-05 632s 111 7.31879733e+03 7.10888474e+03 1.42e-04 9.75e-07 8.73e-05 636s 112 7.31624216e+03 7.11219358e+03 1.36e-04 1.10e-06 8.49e-05 640s 113 7.31449791e+03 7.11356621e+03 1.32e-04 1.10e-06 8.36e-05 645s 114 7.31180612e+03 7.12012055e+03 1.24e-04 1.18e-06 7.97e-05 649s 115 7.30890596e+03 7.12537096e+03 1.16e-04 1.19e-06 7.63e-05 653s 116 7.30780206e+03 7.12964122e+03 1.13e-04 1.19e-06 7.41e-05 657s 117 7.30669004e+03 7.13262634e+03 1.11e-04 9.54e-07 7.24e-05 661s 118 7.30415000e+03 7.13714312e+03 1.04e-04 1.05e-06 6.94e-05 665s 119 7.30127701e+03 7.14228891e+03 9.75e-05 1.20e-06 6.61e-05 669s 120 7.30016364e+03 7.14506762e+03 9.49e-05 1.04e-06 6.45e-05 673s 121 7.29905341e+03 7.14937805e+03 9.21e-05 1.11e-06 6.22e-05 677s 122 7.29680901e+03 7.15313194e+03 8.53e-05 9.97e-07 5.97e-05 681s 123 7.29558320e+03 7.15594325e+03 8.18e-05 1.00e-06 5.80e-05 685s 124 7.29388349e+03 7.16186984e+03 7.73e-05 5.39e-07 5.48e-05 690s 125 7.29160604e+03 7.16771142e+03 7.22e-05 5.49e-07 5.15e-05 694s 126 7.29040100e+03 7.17110758e+03 6.93e-05 7.37e-07 4.96e-05 698s 127 7.28928259e+03 7.17422481e+03 6.65e-05 7.06e-07 4.78e-05 701s 128 7.28816428e+03 7.17839328e+03 6.38e-05 5.57e-07 4.56e-05 705s 129 7.28731586e+03 7.18303018e+03 6.18e-05 1.14e-06 4.33e-05 708s 130 7.28520504e+03 7.18791177e+03 5.75e-05 9.85e-07 4.04e-05 711s 131 7.28363255e+03 7.19303857e+03 5.46e-05 9.89e-07 3.77e-05 715s 132 7.28201873e+03 7.19747105e+03 5.15e-05 1.31e-06 3.51e-05 718s 133 7.27994276e+03 7.20084846e+03 4.74e-05 1.21e-06 3.29e-05 721s 134 7.27897406e+03 7.20281346e+03 4.55e-05 1.20e-06 3.17e-05 725s 135 7.27748327e+03 7.20564103e+03 4.23e-05 9.71e-07 2.99e-05 728s 136 7.27654169e+03 7.20635561e+03 4.05e-05 9.20e-07 2.92e-05 731s 137 7.27634786e+03 7.20906398e+03 4.01e-05 1.04e-06 2.80e-05 734s 138 7.27552608e+03 7.21113514e+03 3.83e-05 8.28e-07 2.68e-05 737s 139 7.27444149e+03 7.21303670e+03 3.61e-05 7.95e-07 2.55e-05 741s 140 7.27370068e+03 7.21646549e+03 3.48e-05 4.12e-07 2.38e-05 744s 141 7.27314131e+03 7.21767634e+03 3.36e-05 5.37e-07 2.31e-05 748s 142 7.27263520e+03 7.21790491e+03 3.26e-05 5.34e-07 2.27e-05 751s 143 7.27234677e+03 7.21997211e+03 3.20e-05 4.82e-07 2.18e-05 755s 144 7.27175543e+03 7.22146952e+03 3.07e-05 4.62e-07 2.09e-05 758s 145 7.27104714e+03 7.22288287e+03 2.93e-05 4.46e-07 2.00e-05 762s 146 7.27041597e+03 7.22474901e+03 2.80e-05 4.22e-07 1.90e-05 766s 147 7.26987037e+03 7.22710620e+03 2.70e-05 2.98e-07 1.78e-05 770s 148 7.26947877e+03 7.22784315e+03 2.61e-05 1.79e-07 1.73e-05 773s 149 7.26881374e+03 7.22911380e+03 2.49e-05 2.19e-07 1.65e-05 777s 150 7.26796732e+03 7.23178763e+03 2.33e-05 1.97e-07 1.50e-05 781s 151 7.26661181e+03 7.23581675e+03 2.09e-05 3.32e-07 1.28e-05 784s 152 7.26588565e+03 7.23768698e+03 1.90e-05 3.01e-07 1.17e-05 788s 153 7.26541642e+03 7.23883849e+03 1.81e-05 2.48e-07 1.11e-05 792s 154 7.26511831e+03 7.23902516e+03 1.75e-05 2.46e-07 1.09e-05 795s 155 7.26434105e+03 7.23981136e+03 1.61e-05 1.79e-07 1.02e-05 798s 156 7.26324281e+03 7.24085948e+03 1.41e-05 5.66e-08 9.31e-06 801s 157 7.26294518e+03 7.24212494e+03 1.34e-05 1.11e-07 8.67e-06 805s 158 7.26198411e+03 7.24329777e+03 1.17e-05 1.49e-07 7.78e-06 808s 159 7.26171594e+03 7.24364971e+03 1.13e-05 1.45e-07 7.52e-06 812s 160 7.26071146e+03 7.24502790e+03 9.61e-06 1.26e-07 6.53e-06 815s 161 7.26003649e+03 7.24785207e+03 8.32e-06 5.68e-08 5.08e-06 819s 162 7.25896311e+03 7.24911248e+03 6.54e-06 7.02e-09 4.11e-06 822s 163 7.25826267e+03 7.25031665e+03 5.39e-06 7.37e-09 3.32e-06 825s 164 7.25745209e+03 7.25118062e+03 4.12e-06 6.04e-09 2.62e-06 828s 165 7.25707390e+03 7.25162217e+03 3.52e-06 5.29e-09 2.27e-06 832s 166 7.25640744e+03 7.25289709e+03 2.43e-06 4.01e-09 1.47e-06 835s 167 7.25624694e+03 7.25324963e+03 2.18e-06 3.55e-09 1.25e-06 839s 168 7.25589503e+03 7.25359042e+03 1.63e-06 2.79e-09 9.64e-07 844s 169 7.25572583e+03 7.25398521e+03 1.35e-06 1.90e-09 7.30e-07 848s 170 7.25567512e+03 7.25435196e+03 1.28e-06 1.12e-09 5.57e-07 854s 171 7.25547981e+03 7.25447166e+03 9.46e-07 8.76e-10 4.25e-07 861s 172 7.25546825e+03 7.25448819e+03 9.27e-07 8.37e-10 4.13e-07 868s 173 7.25540243e+03 7.25452281e+03 8.24e-07 7.69e-10 3.70e-07 876s 174 7.25537092e+03 7.25459739e+03 7.73e-07 6.09e-10 3.26e-07 885s 175 7.25531516e+03 7.25461285e+03 6.90e-07 5.76e-10 2.96e-07 894s 176 7.25525227e+03 7.25480028e+03 5.89e-07 1.71e-10 1.92e-07 902s 177 7.25523644e+03 7.25480431e+03 5.66e-07 1.63e-10 1.84e-07 910s 178 7.25521546e+03 7.25480706e+03 5.30e-07 1.58e-10 1.74e-07 917s 179 7.25510273e+03 7.25484259e+03 3.69e-07 7.45e-11 1.11e-07 925s 180 7.25505838e+03 7.25485855e+03 2.93e-07 4.24e-11 8.54e-08 931s 181 7.25500950e+03 7.25486654e+03 2.21e-07 2.71e-11 6.13e-08 940s 182 7.25489915e+03 7.25487526e+03 3.80e-08 1.19e-11 1.02e-08 945s 183 7.25488357e+03 7.25488246e+03 3.98e-09 9.37e-13 4.82e-10 948s 184 7.25488295e+03 7.25488295e+03 5.25e-09 9.00e-11 2.08e-13 950s Barrier solved model in 184 iterations and 950.50 seconds (745.77 work units)
Optimal objective 7.25488295e+03
Root crossover log...
354068 DPushes remaining with DInf 0.0000000e+00 954s
33663 DPushes remaining with DInf 0.0000000e+00 1041s
11839 DPushes remaining with DInf 0.0000000e+00 1045s
60 DPushes remaining with DInf 0.0000000e+00 1050s
0 DPushes remaining with DInf 0.0000000e+00 1051s
348 PPushes remaining with PInf 0.0000000e+00 1051s
0 PPushes remaining with PInf 0.0000000e+00 1051s
Push phase complete: Pinf 0.0000000e+00, Dinf 2.2543339e-12 1051s
Root simplex log... Iteration Objective Primal Inf. Dual Inf. Time
245611 7.2548829e+03 0.000000e+00 0.000000e+00 1052s
245611 7.2548829e+03 0.000000e+00 0.000000e+00 1053s
Concurrent spin time: 0.11s
Solved with barrier
Root relaxation: objective 7.254883e+03, 245611 iterations, 787.93 seconds (873.11 work units)
Total elapsed time = 1053.55s
Total elapsed time = 1100.80s
Nodes | Current Node | Objective Bounds | Work
Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time
0 0 7254.88295 0 10010 - 7254.88295 - - 1119s
0 0 7265.50596 0 10028 - 7265.50596 - - 4057s
0 0 7266.84702 0 10309 - 7266.84702 - - 4477s
0 0 7267.00887 0 10139 - 7267.00887 - - 4547s
0 0 7267.33760 0 10365 - 7267.33760 - - 5104s
0 0 7267.78979 0 10175 - 7267.78979 - - 5596s
0 0 7267.90539 0 10180 - 7267.90539 - - 5671s
0 0 7267.95151 0 10175 - 7267.95151 - - 6247s
0 0 7267.96845 0 10175 - 7267.96845 - - 6311s
0 0 7269.26459 0 10189 - 7269.26459 - - 7428s
0 0 7269.26459 0 10189 - 7269.26459 - - 7766s
0 0 7269.65564 0 10173 - 7269.65564 - - 8299s
0 0 7269.65564 0 10173 - 7269.65564 - - 8382s
0 0 7269.65564 0 10172 - 7269.65564 - - 8858s
0 2 7269.91843 0 10172 - 7269.91843 - - 9141s
1 5 7699.40235 1 13322 - 7269.91843 - 136922 12122s
3 8 7840.93550 2 12899 - 7529.60656 - 101352 26697s
7 16 8238.94041 3 6196 - 7666.15034 - 243991 48778s
15 24 8246.84854 4 8690 - 7669.21799 - 264092 66906s
23 32 8249.44400 4 7250 - 7669.23769 - 245877 72597s
31 40 8266.16665 5 6971 - 7738.37059 - 233540 76188s
39 48 8290.35109 5 7965 - 7738.37059 - 211013 89166s
47 60 8276.09784 6 7530 - 7983.30773 - 216422 106771s
59 69 8282.99872 7 6625 - 7983.30773 - 197454 128211s
68 81 8291.47829 8 5652 - 7983.30773 - 191676 146293s
80 89 8334.68227 9 6657 - 7983.30773 - 182711 155737s
90 102 8307.98595 10 7433 - 7983.30773 - 171378 166637s
103 116 8325.45121 13 5956 - 7983.30773 - 159003 178183s
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Gurobi Staff
This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support. -
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However, I observed that in the first 48 hours no heuristic was used, and no feasible solution had been founded so far, which is very different compared to the solving process when I run the same model with smaller sampling data: I usually see the heuristic finds a feasible solution before it reaches the nodes.
As long as you do not explicitly turn off all heuristics via Heuristics=0, Gurobi will run heuristics to find feasible solutions. As long as no solution is found, you will not see any heuristic reports. In your case, it looks like finding a feasible point is really challenging.
which is very different compared to the solving process when I run the same model with smaller sampling data
This makes a lot of sense, because finding feasible solution to a smaller model is often easier. Are you sure that a feasible point exists for the big data set? Is the data cleaned up, i.e., are rounding errors taken care off before plugging it into Gurobi?
If you know a (almost) feasible solution, you could provide it to Gurobi as MIP start to possibly improve the solution finding process. You could also try to experiment with the NoRelHeurTime parameter to run a dedicated feasible point heuristic before the root node relaxation has been solved. We discuss the most important parameters for MIPs in the documentation.
Best regards,
Jaromił0 -
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Hi Jaromił,
Thank you so much for the helpful answer! Yes, I believe the feasible points exist and I've seen feasible solutions have been found. I do have one more question related to this: there is a * before the first feasible solution. May I ask what that means? I've attached the log below. Thanks in advance!
103 116 8325.45121 13 5956 - 7983.30773 - 159003 178183s
121 127 8326.75272 15 4700 - 7983.30773 - 146105 194184s
* 124 127 17 8328.2000000 7983.30773 4.14% 143175 194184s
135 95 cutoff 17 8328.20000 7983.30773 4.14% 142763 194185s
167 78 cutoff 10 8328.20000 7983.72953 4.14% 115409 202108s
H 182 78 8319.9000000 7983.72953 4.04% 110957 202108s
184 79 8217.56425 6 6735 8319.90000 7983.72953 4.04% 112299 210453s0 -
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The asterisk * means that a feasible solution has been found via branching and \(\texttt{H}\) means that a heuristic was able to find a feasible solution, cf. MIP logging documentation.
Best regards,
Jaromił0 -
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