current bounds on the number of colors: 0 -- 5 Gurobi 5.0.1 (linux64) logging started Thu Dec 13 19:35:29 2012 Optimize a model with 7 rows, 11 columns and 16 nonzeros Presolve removed 7 rows and 11 columns Presolve time: 0.00s Explored 0 nodes (0 simplex iterations) in 0.00 seconds Thread count was 1 (of 16 available processors) Optimal solution found (tolerance 1.00e-04) Best objective 0.000000000000e+00, best bound 0.000000000000e+00, gap 0.0% current bounds on the number of colors: 0 -- 2 Gurobi 5.0.1 (linux64) logging started Thu Dec 13 19:35:29 2012 Optimize a model with 6 rows, 6 columns and 8 nonzeros Presolve removed 6 rows and 6 columns Presolve time: 0.00s Explored 0 nodes (0 simplex iterations) in 0.00 seconds Thread count was 1 (of 16 available processors) Model objective exceeds cutoff Best objective -, best bound -, gap - optimal solution found: number of colors: 2