current bounds on the number of colors: 0 -- 9 Gurobi 5.0.1 (linux64) logging started Sat Dec 15 16:12:40 2012 Optimize a model with 9 rows, 36 columns and 36 nonzeros Presolve removed 9 rows and 36 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 -- 4 Gurobi 5.0.1 (linux64) logging started Sat Dec 15 16:12:40 2012 Optimize a model with 9 rows, 18 columns and 18 nonzeros Presolve removed 9 rows and 18 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 Sat Dec 15 16:12:40 2012 Optimize a model with 9 rows, 9 columns and 9 nonzeros Presolve removed 9 rows and 9 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% optimal solution found: number of colors: 1