Gurobi 5.0.1 (linux64) logging started Tue Nov 20 05:48:39 2012

Optimize a model with 172 rows, 54 columns and 344 nonzeros
Presolve removed 50 rows and 0 columns
Presolve time: 0.00s
Presolved: 122 rows, 54 columns, 285 nonzeros
Variable types: 0 continuous, 54 integer (54 binary)
Found heuristic solution: objective 18.0000000

Root relaxation: objective 2.166667e+01, 68 iterations, 0.00 seconds

    Nodes    |    Current Node    |     Objective Bounds      |     Work
 Expl Unexpl |  Obj  Depth IntInf | Incumbent    BestBd   Gap | It/Node Time

     0     0   21.66667    0   40   18.00000   21.66667  20.4%     -    0s
H    0     0                      20.0000000   21.66667  8.33%     -    0s
     0     0   21.00000    0   34   20.00000   21.00000  5.00%     -    0s
     0     0   21.00000    0   44   20.00000   21.00000  5.00%     -    0s
     0     0     cutoff    0        20.00000   20.99998  5.00%     -    0s

Cutting planes:
  Gomory: 1
  Zero half: 42

Explored 0 nodes (132 simplex iterations) in 0.01 seconds
Thread count was 1 (of 16 available processors)

Optimal solution found (tolerance 1.00e-04)
Best objective 2.000000000000e+01, best bound 2.000000000000e+01, gap 0.0%