Build (method = -2) #dp: 2615 Step-3' Graph: 84 vertices and 242 arcs (0.01s) Step-4' Graph: 8 vertices and 90 arcs (0.01s) #V4/#V3 = 0.10 #A4/#A3 = 0.37 Ready! (0.01s) Optimize a model with 28 rows, 91 columns and 264 nonzeros Presolve removed 2 rows and 2 columns Presolve time: 0.00s Presolved: 26 rows, 89 columns, 260 nonzeros Variable types: 0 continuous, 89 integer (4 binary) Found heuristic solution: objective 198.0000000 Found heuristic solution: objective 186.0000000 Optimize a model with 26 rows, 89 columns and 260 nonzeros Presolved: 26 rows, 89 columns, 260 nonzeros Root barrier log... Ordering time: 0.00s Barrier statistics: AA' NZ : 9.400e+01 Factor NZ : 3.510e+02 Factor Ops : 6.201e+03 (less than 1 second per iteration) Threads : 1 Objective Residual Iter Primal Dual Primal Dual Compl Time 0 8.45708687e+02 -9.03071011e+02 1.61e+02 3.91e-02 3.08e+01 0s 1 1.78570357e+02 -4.75962997e+02 6.44e+00 3.33e-16 4.11e+00 0s 2 9.41991956e+01 -9.52824554e+00 8.72e-03 3.89e-16 5.34e-01 0s 3 5.13472511e+01 3.19727827e+01 1.38e-04 5.45e-16 9.84e-02 0s 4 5.01009475e+01 4.88513388e+01 1.07e-05 4.86e-16 6.34e-03 0s 5 5.00001097e+01 4.99989365e+01 4.97e-10 5.55e-16 5.96e-06 0s 6 5.00000000e+01 5.00000000e+01 1.76e-14 4.85e-16 6.03e-12 0s Barrier solved model in 6 iterations and 0.00 seconds Optimal objective 5.00000000e+01 Root relaxation: objective 5.000000e+01, 77 iterations, 0.00 seconds Nodes | Current Node | Objective Bounds | Work Expl Unexpl | Obj Depth IntInf | Incumbent BestBd Gap | It/Node Time * 0 0 0 50.0000000 50.00000 0.0% - 0s Explored 0 nodes (77 simplex iterations) in 0.00 seconds Thread count was 1 (of 8 available processors) Optimal solution found (tolerance 0.00e+00) Best objective 5.000000000000e+01, best bound 5.000000000000e+01, gap 0.0% Preprocessing time: 0.02 seconds Gurobi run time: 0.00 seconds Total run time: 0.02 seconds Objective: 50 Solution: 11 x [5, 6, 19, 20] 2 x [6, 9, 13, 19] 9 x [11, 12, 13, 18] 1 x [4, 15, 16, 20] 7 x [3, 4, 8, 16] 2 x [4, 10, 17, 20] 9 x [1, 4, 7, 15] 2 x [2, 4, 7, 9] 6 x [10, 13, 15, 17] 1 x [7, 8, 14, 15]