Build (method = -2) #dp: 2620 Step-3' Graph: 81 vertices and 236 arcs (0.01s) Step-4' Graph: 8 vertices and 90 arcs (0.01s) #V4/#V3 = 0.10 #A4/#A3 = 0.38 Ready! (0.01s) Optimize a model with 28 rows, 91 columns and 261 nonzeros Presolve removed 4 rows and 5 columns Presolve time: 0.00s Presolved: 24 rows, 86 columns, 250 nonzeros Variable types: 0 continuous, 86 integer (8 binary) Found heuristic solution: objective 198.0000000 Found heuristic solution: objective 165.0000000 Optimize a model with 24 rows, 86 columns and 250 nonzeros Presolved: 24 rows, 86 columns, 250 nonzeros Root barrier log... Ordering time: 0.00s Barrier statistics: AA' NZ : 8.700e+01 Factor NZ : 3.000e+02 Factor Ops : 4.900e+03 (less than 1 second per iteration) Threads : 1 Objective Residual Iter Primal Dual Primal Dual Compl Time 0 1.14580306e+03 -1.43949383e+03 1.58e+02 4.75e-02 4.19e+01 0s 1 2.72453584e+02 -5.54028834e+02 8.44e+00 5.55e-16 5.65e+00 0s 2 1.16176799e+02 -6.12936560e+01 9.01e-03 1.67e-15 9.53e-01 0s 3 5.38693381e+01 3.06049026e+01 1.53e-04 3.33e-16 1.23e-01 0s 4 5.05340898e+01 4.94411563e+01 2.71e-06 3.33e-16 5.78e-03 0s 5 5.02503407e+01 5.02485151e+01 2.56e-09 3.33e-16 9.66e-06 0s 6 5.02500000e+01 5.02500000e+01 2.50e-13 2.22e-16 9.71e-12 0s Barrier solved model in 6 iterations and 0.00 seconds Optimal objective 5.02500000e+01 Root relaxation: objective 5.025000e+01, 71 iterations, 0.00 seconds Nodes | Current Node | Objective Bounds | Work Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time 0 0 50.25000 0 6 165.00000 50.25000 69.5% - 0s H 0 0 51.0000000 50.25000 1.47% - 0s Explored 0 nodes (93 simplex iterations) in 0.00 seconds Thread count was 1 (of 8 available processors) Optimal solution found (tolerance 0.00e+00) Best objective 5.100000000000e+01, best bound 5.100000000000e+01, gap 0.0% Preprocessing time: 0.02 seconds Gurobi run time: 0.00 seconds Total run time: 0.02 seconds Objective: 51 Solution: 1 x [2, 4, 6] 12 x [3, 6, 7, 11] 3 x [3, 14, 14, 18] 1 x [2, 5, 17] 15 x [2, 15, 17, 19] 3 x [1, 7, 14, 20] 6 x [8, 11, 12, 20] 1 x [8, 12, 20] 4 x [1, 9, 14, 16] 1 x [1, 12, 13, 14] 1 x [1, 10, 12, 15] 3 x [4, 14, 15, 16]