current bounds on the number of colors: 0 -- 2 Gurobi 5.0.1 (linux64) logging started Fri Dec 14 18:19:09 2012 Optimize a model with 2 rows, 2 columns and 2 nonzeros Presolve removed 2 rows and 2 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