> I’m trying to optimize a problem. What I do is I maximize and minimize > same objective function (different order gives same results). What > happens though is that minimizing gives optimal solution but > maximizing gives error. Even stranger is that when maximizing in > terminal output it says that solution is unbounded but glp_simplex > returns an error and status in undefined. In the end I just don’t know > what value should I trust. Here is output from maximization followed > by minimization.
[...] > * 19415: obj = 2.908302405e+01 infeas = 9.459e-13 (4816) > PROBLEM HAS UNBOUNDED SOLUTION > glp_simplex: unable to recover undefined or non-optimal solution > ERR_CODE: GLP_ENODFS (11) > STATUS: GLP_UNDEF (1) The lp preprocessor (presolver), which is enabled by default in glpsol, is not able to recover the solution to the original lp from the solution to a preprocessed lp if the solution is not optimal. Only optimal solutions can be recovered; in all other cases the lp preprocessor sets the solution status for the original lp instance to GLP_UNDEF (undefined). You may disable the lp preprocessor (--nopresol) to obtain the original basic solution produced by the simplex solver. FYI: The most recent version of glpk is 4.47. _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
