Gurobi 5.0.1 (linux64) logging started Wed Apr 24 02:46:09 2013

Optimize a model with 55574 rows, 54834 columns and 219114 nonzeros
Presolve removed 3935 rows and 0 columns
Presolve time: 0.34s
Presolved: 51639 rows, 54834 columns, 211244 nonzeros
Variable types: 54760 continuous, 74 integer (74 binary)

Root relaxation: objective 8.146644e+04, 9748 iterations, 1.78 seconds

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

     0     0 81466.4366    0    4          - 81466.4366     -      -    2s
H    0     0                    82529.000000 81466.4366  1.29%     -    2s
     0     0 81467.0583    0    5 82529.0000 81467.0583  1.29%     -    2s
     0     2 81471.3505    0    5 82529.0000 81471.3505  1.28%     -    4s
H    2     2                    81927.119374 81546.0467  0.47%  62.5    4s
H    3     3                    81727.534247 81578.1938  0.18%  64.7    4s
*    4     3               4    81581.000000 81581.0000   0.0%  55.8    4s

Cutting planes:
  Gomory: 1
  Flow cover: 1

Explored 5 nodes (9986 simplex iterations) in 4.75 seconds
Thread count was 1 (of 16 available processors)

Optimal solution found (tolerance 1.00e-04)
Best objective 8.158100000000e+04, best bound 8.158100000000e+04, gap 0.0%