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Solution and incumbent are different

Open SupplyChef opened this issue 1 year ago • 1 comments

Hello,

I am seeing a bit of a strange behavior. I have a MIP problem. It solves fine as seen in the log. The incumbent objective (maximization) is around 16856993205.89 at the time limit. But when the final results are reported the objective is very different. Am I misunderstanding the logs?

At the moment I only see this on a very big model. Not sure how to provide a model to repro.

Thanks.

Logs: ... L 880 830 3 0.00% 21322168436.27 16856993205.89 26.49% 10690 1724 111 1644k 1767.3s 1019 969 4 0.00% 21322168436.27 16856993205.89 26.49% 10690 1724 118 1890k 3782.4s

Solving report Status Time limit reached Primal bound 16856993205.9 Dual bound 21322168436.3 Gap 26.49% (tolerance: 0.01%) Solution status feasible -19188000000 (objective) 0 (bound viol.) 0 (int. viol.) 0 (row viol.) Timing 3782.37 (total) 1.28 (presolve) 0.00 (postsolve) Nodes 1019 LP iterations 1890255 (total) 635988 (strong br.) 44157 (separation) 186341 (heuristics)

SupplyChef avatar Mar 22 '24 18:03 SupplyChef

But when the final results are reported the objective is very different.

What is the output of JuMP.solution_summary(model) after solving?

What is the value of JuMP.objective_value(model)?

It solves fine as seen in the log

It stopped due to a time limit?

odow avatar Mar 23 '24 00:03 odow

I am having difficulties reproducing the problem reliably. I believe it occurs when the problem is badly scaled. I think you can close this issue and I can re-open if I find a reliable repro. Thanks.

SupplyChef avatar Apr 11 '24 15:04 SupplyChef