Thank you for your comments and providing the patch. > > > I think there is an issue with the way tspsol works: The rounding > heuristic of glp_intopt runs after row generation (when no row was > added) and may give an integer solution with subtours. The heuristic > only checks that the solution satisfies the original problem, so no > subtour elimination constraints are checked. Moreover, an appropriate > constraint may not have been added yet.
You are perfectly correct. > > > To avoid this, the rounding heuristic should be disabled. > Unfortunately, there is no control parameter for this in glp_iocp, so > I'm attaching an awful hack to disable it from the tspsol callback. > This is only in case anyone gets an "Assertion failed: kk <= n" error > and wants to check if this is the reason, I would advise against using > it for any other reason. > Probably the fact of specifying the callback routine can be used as a flag to disable primal heuristics, because the callback routine itself is able to apply heuristics performing necessary feasibility checks. Andrew Makhorin _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
