Hi, in some seldom situations GLPK fails with an "internal error" when it tries to generate a mixed cover cut. Unfortunately, I did not manage to generate a mps file for reproduction (the problem appears inside a B&B, and with a generated mps file, it is working fine), so I send you only the output. Maybe you have some idea under which circumstances b could be smaller or equal 0 and let the GLPK solve return with some error code. :-)
ipp_basic_tech: 0 row(s) and 0 column(s) removed ipp_reduce_bnds: 2 pass(es) made, 14 bound(s) reduced ipp_basic_tech: 0 row(s) and 0 column(s) removed ipp_reduce_coef: 1 pass(es) made, 0 coefficient(s) reduced lpx_intopt: presolved MIP has 68 rows, 72 columns, 226 non-zeros lpx_intopt: 16 integer columns, 10 of which are binary lpx_adv_basis: size of triangular part = 68 Solving LP relaxation... 0: objval = 2.425852301e+08 infeas = 1.000000000e+00 (0) 25: objval = 3.735170535e+08 infeas = 0.000000000e+00 (0) * 25: objval = 3.735170535e+08 infeas = 0.000000000e+00 (0) * 48: objval = 6.588564313e+04 infeas = 0.000000000e+00 (0) OPTIMAL SOLUTION FOUND Creating the conflict graph... The conflict graph is either empty or too big Generating cutting planes... & 48: obj = 6.588564313e+04 frac = 12 cuts = 0 (0) GLPK internal error: b > 0.0; file ../../../GAMSlinks-trunk/ThirdParty/Glpk/glpk/src/glplpx12.c, line 796 Best, Stefan _______________________________________________ Bug-glpk mailing list Bug-glpk@gnu.org http://lists.gnu.org/mailman/listinfo/bug-glpk