Build (method = -2) #dp: 15585 Step-3' Graph: 182 vertices and 539 arcs (0.10s) Step-4' Graph: 14 vertices and 203 arcs (0.10s) #V4/#V3 = 0.08 #A4/#A3 = 0.38 Ready! (0.10s) Optimize a model with 60 rows, 204 columns and 588 nonzeros Presolve removed 6 rows and 6 columns Presolve time: 0.00s Presolved: 54 rows, 198 columns, 572 nonzeros Variable types: 0 continuous, 198 integer (152 binary) Found heuristic solution: objective 46.0000000 Optimize a model with 54 rows, 198 columns and 572 nonzeros Presolved: 54 rows, 198 columns, 572 nonzeros Root barrier log... Ordering time: 0.00s Barrier statistics: AA' NZ : 2.090e+02 Factor NZ : 6.500e+02 Factor Ops : 1.213e+04 (less than 1 second per iteration) Threads : 1 Objective Residual Iter Primal Dual Primal Dual Compl Time 0 2.95437530e+02 -3.91183265e+02 4.24e+01 2.27e-02 3.27e+00 0s 1 5.41319273e+01 -6.64858137e+01 3.43e-01 2.78e-16 3.23e-01 0s 2 2.49704592e+01 -1.95967996e+00 4.94e-02 2.22e-16 6.87e-02 0s 3 1.35541934e+01 1.09863010e+01 1.51e-03 1.67e-16 6.41e-03 0s 4 1.25019348e+01 1.24853892e+01 4.59e-13 2.29e-16 4.14e-05 0s 5 1.25000000e+01 1.25000000e+01 4.73e-14 1.18e-16 4.56e-11 0s Barrier solved model in 5 iterations and 0.00 seconds Optimal objective 1.25000000e+01 Root relaxation: objective 1.250000e+01, 142 iterations, 0.00 seconds Nodes | Current Node | Objective Bounds | Work Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time 0 0 12.50000 0 6 46.00000 12.50000 72.8% - 0s H 0 0 13.0000000 12.50000 3.85% - 0s Explored 0 nodes (194 simplex iterations) in 0.01 seconds Thread count was 1 (of 8 available processors) Optimal solution found (tolerance 0.00e+00) Best objective 1.300000000000e+01, best bound 1.300000000000e+01, gap 0.0% Preprocessing time: 0.10 seconds Gurobi run time: 0.01 seconds Total run time: 0.11 seconds Objective: 13 Solution: 1 x [18, 27, 28, 36] 1 x [14, 16, 19, 26] 1 x [2, 13, 25, 31] 1 x [7, 23, 39, 45] 1 x [8, 37, 41, 42] 1 x [4, 10, 35, 46] 1 x [1, 33, 38, 45] 1 x [1, 3, 7] 1 x [30, 32, 34, 44] 1 x [22, 24, 29, 43] 1 x [17, 20, 21, 40] 1 x [5, 12, 23] 1 x [6, 9, 11, 15]