> It was actually more economical for me to go to the source code on > this. In the time it would take glpsol to provide the KKT info > (several hours), I threw some lines into glpk and got the info I > needed. Of course, I have no idea if what I added will break other > things or will work for all cases, it just gave me what I needed. For > completeness of this discussion thread, here is the message I was > receiving originally:
> lpx_read_cpxlp: reading problem data from `dw_monolithic.cplex'... > lpx_read_cpxlp: 440350 rows, 299500 columns, 969398 non-zeros > lpx_read_cpxlp: 299500 integer columns, all of which are binary > lpx_read_cpxlp: 1089422 lines were read > glp_simplex: original LP has 440350 rows, 299500 columns, 969398 non-zeros > PROBLEM HAS NO PRIMAL FEASIBLE SOLUTION > glp_intopt: optimal basis to initial LP relaxation not provided > Time used: 1.0 secs > Memory used: 211.3 Mb (221541952 bytes) > And with less than 10-20 lines of additional code I could get this: > lpx_read_cpxlp: reading problem data from `dw_monolithic.cplex'... > lpx_read_cpxlp: 440350 rows, 299500 columns, 969398 non-zeros > lpx_read_cpxlp: 299500 integer columns, all of which are binary > lpx_read_cpxlp: 1089422 lines were read > glp_simplex: original LP has 440350 rows, 299500 columns, 969398 non-zeros > General Row Analysis. Row 437495. > PROBLEM HAS NO PRIMAL FEASIBLE SOLUTION > The problem row was 437495, DepartCap(CLE,2). > glp_intopt: optimal basis to initial LP relaxation not provided > Time used: 0.0 secs > Memory used: 211.3 Mb (221541956 bytes) > This is going to help me debug my code for generating my input file > to glpsol. I'd be happy to send you my changes, Andrew, if you > thought it would be helpful. They seem very minor, but again, I can't > say I've considered every implication of their inclusion. Probably printing information about the row/column, which is found infeasible, would be useful. Thank you for your suggestion. However, I would like to note that that row/column is the root of a tree, where any row/column may cause infeasibility, and it would be difficult to track all such rows/columns because of recursive nature of the presolving process. Andrew Makhorin _______________________________________________ Help-glpk mailing list Help-glpk@gnu.org http://lists.gnu.org/mailman/listinfo/help-glpk