Horrible presolve time and bad solution
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The log is as follows, could anyone give some suggestions on what should I do?
Gurobi 9.0.2 (win64, Matlab) logging started Mon May 18 15:23:10 2020
Gurobi Optimizer version 9.0.2 build v9.0.2rc0 (win64)
Optimize a model with 6643716 rows, 6188940 columns and 31232016 nonzeros
Model fingerprint: 0x8b7e45d3
Variable types: 2400 continuous, 6186540 integer (6186540 binary)
Coefficient statistics:
Matrix range [1e-01, 2e+03]
Objective range [3e-01, 2e+01]
Bounds range [1e+00, 1e+00]
RHS range [1e+00, 3e+03]
Found heuristic solution: objective 95.0700000
Presolve removed 6248430 rows and 1063632 columns (presolve time = 33s) ...
Presolve removed 6248430 rows and 1063632 columns (presolve time = 81s) ...
Presolve removed 6248430 rows and 1063632 columns
Presolve time: 7199.51s
Explored 0 nodes (0 simplex iterations) in 7432.19 seconds
Thread count was 1 (of 12 available processors)
Solution count 1: 95.07
Time limit reached
Best objective 9.507000000000e+01, best bound -, gap -
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Hey Liam,
You are trying to solve a pretty huge model, containing over 6 million binary variables and more than 30 million nonzeroes. You may want to reduce the number of presolving rounds via PrePasses=1 or Presolve=1 to reduce the time spent in presolving.
Cheers,
Matthias0 -
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