HiGHS icon indicating copy to clipboard operation
HiGHS copied to clipboard

HiGHS Infeasible when Presolve is Off

Open erdembanak opened this issue 1 year ago • 1 comments

For some problems, HiGHS returns the problem as infeasible when CPLEX and CBC find the optimal solution (3.1108620188e+11). Since there were issues about presolve, I have switched off presolve but the problem is still infeasible.

infeasible_presolve_off.mps.txt

erdembanak avatar May 19 '23 15:05 erdembanak

Thanks!

jajhall avatar May 19 '23 15:05 jajhall

Just run this with Gurobi and it says,

Matrix range [1e+00, 1e+09] Objective range [1e+00, 1e+00] Bounds range [1e+00, 1e+00] RHS range [1e-01, 2e+03] Warning: Model contains large matrix coefficients Consider reformulating model or setting NumericFocus parameter to avoid numerical issues.

and, although it finds a solution with objective 3.110862018838e+11,

Warning: max constraint violation (1.8311e-04) exceeds tolerance

So, since the problem may be infeasible to within the primal tolerance, it may be futile to try to identify whether HiGHS is actually wrong

jajhall avatar Apr 05 '24 22:04 jajhall