> Thanks a lot. But now I tried a different parameter combination > (please > find them attached in the model_2.mps file). The sentence: > > glpsol --mps --intopt model_2.mps > > > produces the following: > > > lpx_read_mps: reading problem data from `model_2.mps'... > lpx_read_mps: problem name not specified > lpx_read_mps: 65 rows, 54 columns, 240 non-zeros > lpx_read_mps: 54 integer columns, none of which are binary > lpx_read_mps: 239 cards were read > ipp_basic_tech: 2 row(s) and 0 column(s) removed > ipp_reduce_bnds: 2 pass(es) made, 18 bound(s) reduced > ipp_basic_tech: 7 row(s) and 0 column(s) removed > ipp_reduce_coef: 1 pass(es) made, 0 coefficient(s) reduced > lpx_intopt: presolved MIP has 56 rows, 54 columns, 198 non-zeros > lpx_intopt: 54 integer columns, none of which are binary > lpx_adv_basis: size of triangular part = 56 > Solving LP relaxation... > 0: objval = -2.520000000e+003 infeas = > 1.000000000e+000 (0) > 29: objval = 2.017999987e+003 infeas = > 0.000000000e+000 (0) > * 29: objval = 2.017999987e+003 infeas = > 0.000000000e+000 (0) > * 35: objval = 6.229999868e+002 infeas = > 4.547473509e-013 (0) > OPTIMAL SOLUTION FOUND > Integer optimization begins... > Objective function is integral > + 35: mip = not found yet >= -inf (1; > 0) > Assertion failed: x >= lb; glpmip2.c; line 230 > > > > which seems to be a similar mistake. Although I don't think it is > an > unfeasible problem instance, may this be connected to > unfeasibility > issues? Thanks, >
Now to solve your instance the mip pesolver should be disabled due to the same reason: lpx_read_mps: reading problem data from `model_2.mps'... lpx_read_mps: problem name not specified lpx_read_mps: 65 rows, 54 columns, 240 non-zeros lpx_read_mps: 54 integer columns, none of which are binary lpx_read_mps: 239 cards were read lpx_simplex: original LP has 65 rows, 54 columns, 240 non-zeros lpx_simplex: presolved LP has 63 rows, 51 columns, 216 non-zeros lpx_adv_basis: size of triangular part = 63 0: objval = -2.520000000e+03 infeas = 1.000000000e+00 (0) 27: objval = 6.229999868e+02 infeas = 0.000000000e+00 (0) OPTIMAL SOLUTION FOUND Integer optimization begins... Objective function is integral + 27: mip = not found yet >= -inf (1; 0) + 27: mip = 6.229999868e+02 >= 6.230000000e+02 < 0.1% (1; 0) + 27: mip = 6.229999868e+02 >= tree is empty 0.0% (0; 1) INTEGER OPTIMAL SOLUTION FOUND Time used: 0.0 secs Memory used: 0.1M (134576 bytes) Probably the troubles occur because some integer variables take on relatively large values. I think reformulating the problem could avoid this error. However, it is a lack of the implementation. Andrew Makhorin _______________________________________________ Help-glpk mailing list Help-glpk@gnu.org http://lists.gnu.org/mailman/listinfo/help-glpk