Build (method = -2) #dp: 4890 Step-3' Graph: 774 vertices and 2315 arcs (0.03s) Step-4' Graph: 527 vertices and 1821 arcs (0.03s) #V4/#V3 = 0.68 #A4/#A3 = 0.79 Ready! (0.03s) Optimize a model with 545 rows, 1822 columns and 4416 nonzeros Presolve removed 187 rows and 344 columns Presolve time: 0.03s Presolved: 358 rows, 1478 columns, 4295 nonzeros Variable types: 0 continuous, 1478 integer (81 binary) Found heuristic solution: objective 68.0000000 Optimize a model with 358 rows, 1478 columns and 4295 nonzeros Presolve removed 1 rows and 1 columns Presolved: 357 rows, 1477 columns, 4305 nonzeros Root barrier log... Ordering time: 0.00s Barrier statistics: AA' NZ : 2.795e+03 Factor NZ : 1.316e+04 Factor Ops : 7.404e+05 (less than 1 second per iteration) Threads : 1 Objective Residual Iter Primal Dual Primal Dual Compl Time 0 8.05198043e+02 -1.89934833e+04 2.84e+04 3.73e-02 5.29e+01 0s 1 3.10524143e+02 -9.97288996e+03 5.25e+03 3.55e-15 1.11e+01 0s 2 1.55933608e+02 -3.75690760e+03 1.02e+03 2.00e-15 2.59e+00 0s 3 7.70785196e+01 -7.30805482e+02 9.63e+01 2.94e-15 3.71e-01 0s 4 5.30618140e+01 -2.70568887e+02 1.28e+01 2.36e-15 1.20e-01 0s 5 4.91091669e+01 -1.01160493e+02 8.13e+00 2.16e-15 5.48e-02 0s 6 4.25202952e+01 -3.62913954e+01 3.86e+00 2.21e-15 2.79e-02 0s 7 3.60877999e+01 -1.06133690e+00 1.35e+00 2.82e-15 1.29e-02 0s 8 3.40201000e+01 1.01069216e+01 8.95e-01 2.58e-15 8.28e-03 0s 9 3.16704840e+01 2.17700733e+01 1.93e-01 2.86e-15 3.38e-03 0s 10 3.10513379e+01 3.05648042e+01 3.31e-04 1.83e-15 1.64e-04 0s 11 3.10001786e+01 3.09995158e+01 2.28e-07 1.77e-15 2.23e-07 0s 12 3.10000000e+01 3.10000000e+01 3.60e-12 2.08e-15 2.25e-13 0s Barrier solved model in 12 iterations and 0.03 seconds Optimal objective 3.10000000e+01 Root relaxation: objective 3.100000e+01, 920 iterations, 0.04 seconds Nodes | Current Node | Objective Bounds | Work Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time * 0 0 0 31.0000000 31.00000 0.0% - 0s Explored 0 nodes (920 simplex iterations) in 0.09 seconds Thread count was 1 (of 8 available processors) Optimal solution found (tolerance 0.00e+00) Best objective 3.100000000000e+01, best bound 3.100000000000e+01, gap 0.0% Preprocessing time: 0.05 seconds Gurobi run time: 0.09 seconds Total run time: 0.14 seconds Objective: 31 Solution: 4 x [1, 2, 5, 7, 8, 11] 1 x [1, 2, 7, 8, 10, 11, 15] 1 x [1, 2, 7, 8, 15, 16, 18] 2 x [1, 3, 6, 7, 8] 2 x [1, 5, 6, 7, 8, 10] 4 x [1, 5, 7, 8, 10, 11, 15, 18] 2 x [1, 6, 7, 8, 10, 15, 17] 2 x [1, 6, 7, 8, 10, 15, 18] 1 x [4, 5, 7, 8, 11] 1 x [4, 7, 8, 10, 12, 13, 15, 18] 2 x [5, 6, 7, 8, 9, 12, 15] 3 x [5, 6, 7, 10, 11] 4 x [5, 7, 8, 9, 10, 15] 1 x [5, 7, 8, 9, 12, 15, 18] 1 x [7, 8, 10, 11, 12, 14, 15]