current bounds on the number of colors: 0 -- 8 Gurobi 5.0.1 (linux64) logging started Sat Dec 15 16:12:39 2012 Optimize a model with 8 rows, 32 columns and 32 nonzeros Presolve removed 8 rows and 32 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 16:12:39 2012 Optimize a model with 8 rows, 16 columns and 16 nonzeros Presolve removed 8 rows and 16 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 16:12:39 2012 Optimize a model with 8 rows, 8 columns and 8 nonzeros Presolve removed 8 rows and 8 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