> > solution and try again. (I say 'resembles' because the TSP has a > > special structure with permits other ways to avoid loops, these other > > ways don't work here). > > > Except when I tried it didn't work, because the reason GLP_IROWGEN is > > called with the solution to the LP relaxation, at which point you have > > non-integer variables and determining problematic loops isn't > > possible.
It is possible. Moreover, it is much better to add subtour elimination constraints as early as possible, because this may significantly reduce the size of the search tree. To generate such constraints for *fractional* solutions to lp relaxation you may use a standard technique based on finding a min cut in a capacitated network. If you are interested, I could provide a detailed example (from glpk 4.9). See also glpk/examples/cplex/README. _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
