Gurobi 5.0.1 (linux64) logging started Mon Feb  4 17:19:28 2013

Optimize a model with 1833 rows, 54313 columns and 2934743 nonzeros
Presolve removed 48 rows and 309 columns (presolve time = 5s) ...
Presolve removed 50 rows and 324 columns
Presolve time: 9.81s
Presolved: 1783 rows, 53989 columns, 2912775 nonzeros
Variable types: 0 continuous, 53989 integer (53989 binary)
Found heuristic solution: objective 31760.000000

Root simplex log...

Iteration    Objective       Primal Inf.    Dual Inf.      Time
    8350    2.0457505e+04   4.405198e+02   0.000000e+00      5s
   11860    2.0626991e+04   4.300365e+02   0.000000e+00     10s
   14460    2.0675038e+04   2.311925e+02   0.000000e+00     15s
   15225    2.0677500e+04   0.000000e+00   0.000000e+00     18s

Root relaxation: objective 2.067750e+04, 15225 iterations, 17.63 seconds

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

     0     0 20677.5000    0   92 31760.0000 20677.5000  34.9%     -   28s
H    0     0                    22193.000000 20677.5000  6.83%     -   29s
H    0     0                    20754.000000 20677.5000  0.37%     -   30s
H    0     0                    20713.000000 20677.5000  0.17%     -   31s
     0     0 20679.7500    0  117 20713.0000 20679.7500  0.16%     -   36s
H    0     0                    20707.000000 20679.7500  0.13%     -   52s
*    0     0               0    20681.000000 20681.0000   0.0%     -   57s

Explored 0 nodes (28918 simplex iterations) in 57.85 seconds
Thread count was 1 (of 16 available processors)

Optimal solution found (tolerance 1.00e-04)
Best objective 2.068100000000e+04, best bound 2.068100000000e+04, gap 0.0%