MPS Solver Results
Problem: air05.mps (MIPLIB benchmark)
Description: Airline crew scheduling - set partitioning problem
Problem Characteristics
- Variables: 7195 (all binary)
- Constraints: 426
- Nonzeros: 52121
- Best Known Optimal: 26374
Gap Tolerance Comparison
Comparing different MIP relative gap tolerances to show trade-off between solution quality and solve time.
Run Configuration
- Time Limit: 60 seconds
- cuOpt Version: 26.2.0
- Device: Quadro RTX 8000 (47.24 GiB VRAM)
- CPU: AMD Ryzen Threadripper PRO 3975WX (32 cores)
Results Summary
| Gap Tolerance | Objective | Gap to Optimal | Solve Time | Nodes Explored |
|---|---|---|---|---|
| 0.1% | 26374 | 0.00% | 8.42s | 386 |
| 1.0% | 26491 | 0.44% | 3.23s | 328 |
Key Observations
- Tighter gap finds optimal: The 0.1% gap tolerance found the exact best-known optimal solution (26374)
- Trade-off: The looser 1.0% gap converged faster (3.2s vs 8.4s) but with 0.44% suboptimality
- Both are fast: cuOpt solved this 7195-variable MILP in under 10 seconds
Detailed Solver Output (0.1% gap)
Solving a problem with 426 constraints, 7195 variables (7195 integers), and 52121 nonzeros
Presolve removed: 90 constraints, 1116 variables, 16171 nonzeros
Presolved problem: 336 constraints, 6079 variables, 35950 nonzeros
Root relaxation objective +2.58776093e+04
Strong branching using 7 threads and 222 fractional variables
Explored 386 nodes in 7.73s.
Optimal solution found within relative MIP gap tolerance (1.0e-03)
Solution objective: 26374.000000
relative_mip_gap 0.000992
total_solve_time 8.421934Detailed Solver Output (1.0% gap)
Solving a problem with 426 constraints, 7195 variables (7195 integers), and 52121 nonzeros
Presolve removed: 90 constraints, 1116 variables, 16171 nonzeros
Presolved problem: 336 constraints, 6079 variables, 35950 nonzeros
Root relaxation objective +2.58776093e+04
Strong branching using 63 threads and 222 fractional variables
Explored 328 nodes in 1.09s.
Optimal solution found within relative MIP gap tolerance (1.0e-02)
Solution objective: 26491.000000
relative_mip_gap 0.009669
total_solve_time 3.233650Usage
# Default: download air05.mps and solve with comparison
python model.py --compare --time-limit 60
# Solve custom MPS file
python model.py --file path/to/problem.mps --time-limit 300 --mip-gap 0.001