Gurobi 5.0.1 (linux64) logging started Wed Apr 24 01:55:49 2013

Optimize a model with 44286 rows, 43626 columns and 174306 nonzeros
Presolve removed 1544 rows and 0 columns
Presolve time: 0.26s
Presolved: 42742 rows, 43626 columns, 171218 nonzeros
Variable types: 43560 continuous, 66 integer (66 binary)

Root relaxation: objective 6.796769e+04, 9528 iterations, 1.66 seconds

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

     0     0 67967.6945    0    4          - 67967.6945     -      -    2s
H    0     0                    68436.000000 67967.6945  0.68%     -    2s
H    0     0                    68063.000000 67967.6945  0.14%     -    2s
     0     0 67993.5225    0    6 68063.0000 67993.5225  0.10%     -    2s
     0     0 67993.5225    0    4 68063.0000 67993.5225  0.10%     -    3s
     0     0 67996.5709    0    5 68063.0000 67996.5709  0.10%     -    3s
     0     0 67996.5709    0    5 68063.0000 67996.5709  0.10%     -    4s
     0     0 67996.5709    0    5 68063.0000 67996.5709  0.10%     -    4s
     0     0 67996.5709    0    5 68063.0000 67996.5709  0.10%     -    4s
     0     0 68062.5200    0    1 68063.0000 68062.5200  0.00%     -    4s

Cutting planes:
  Gomory: 1
  Flow cover: 7

Explored 0 nodes (12606 simplex iterations) in 4.71 seconds
Thread count was 1 (of 16 available processors)

Optimal solution found (tolerance 1.00e-04)
Best objective 6.806300000000e+04, best bound 6.806252000000e+04, gap 0.0007%