SCIP get stuck during presolving #4999
Description
What version of OR-Tools and what language are you using?
Version: 9.12
Language: Pyhton
Which solver are you using SCIP
What operating system Linux
What did you do?
I’m seeing a similar issue where SCIP gets stuck between presolving and solving. I upgraded OR-Tools to the latest version, but the problem persists. Before upgrading to version 9.12, I didn’t have any issues—this started immediately after the upgrade.
Sorry, I can’t share my LP because it’s confidential, but below is the point where it gets stuck:
presolving: (round 1, fast) 212 del vars, 893 del conss, 0 add conss, 92 chg bounds, 0 chg sides, 140 chg coeffs, 0 upgd conss, 0 impls, 4193 clqs (round 2, fast) 212 del vars, 983 del conss, 0 add conss, 92 chg bounds, 0 chg sides, 140 chg coeffs, 0 upgd conss, 0 impls, 4193 clqs (round 3, medium) 263 del vars, 983 del conss, 0 add conss, 92 chg bounds, 0 chg sides, 140 chg coeffs, 0 upgd conss, 0 impls, 4091 clqs ... (round 105, exhaustive) 2126 del vars, 6535 del conss, 224 add conss, 92 chg bounds, 23 chg sides, 156 chg coeffs, 6280 upgd conss, 0 impls, 56298 clqs (0.8s) probing: 181/642 (28.2%) - 10 fixings, 67 aggregations, 76879 implications, 0 bound changes (0.8s) probing aborted: 50/50 successive totally useless probings (round 106, exhaustive) 2127 del vars, 6535 del conss, 224 add conss, 92 chg bounds, 23 chg sides, 156 chg coeffs, 6280 upgd conss, 0 impls, 56572 clqs (round 107, fast) 2127 del vars, 6536 del conss, 224 add conss, 92 chg bounds, 23 chg sides, 156 chg coeffs, 6280 upgd conss, 0 impls, 56572 clqs (round 108, exhaustive) 2127 del vars, 6537 del conss, 224 add conss, 92 chg bounds, 23 chg sides, 156 chg coeffs, 6280 upgd conss, 0 impls, 56572 clqs (0.9s) probing: 186/642 (29.0%) - 10 fixings, 67 aggregations, 76879 implications, 0 bound changes (0.9s) probing aborted: 50/50 successive totally useless probings Deactivated symmetry handling methods, since SCIP was built without symmetry detector (SYM=none).
After the message:
Deactivated symmetry handling methods, since SCIP was built without symmetry detector (SYM=none).
no further logs are printed. I also set a time limit of 60 seconds, but even after 10 minutes the solver is still running and nothing seems to happen.
Do you think it's related to the same issue. Also before upgrading to 9.12 I was on "ortools~=9.9.0" and there was no problem at the time.