Michael, I've been hoping it can be done with binary variables in GMPL as I'm still trying to refine the problem statement. I'd like to be confident it's a good choice before coding it. I'd also like to improve my grasp of expressing problems in GMPL. I started out using CPLEX format and switching to GMPL has been a huge improvement when trying to explore various problem formulations.
With a two step solution if i set the weights to 0 or 1 I can probably get what I want by light editing of the data file using awk to add the weighting array. Not perhaps as elegant as solving in a single step, but it would allow using a pure LP solution and avoid the performance hit that a MIP formulation implies. Until I read your suggestion I'd been thinking along the lines of writing a whole new data file which was pretty painful to contemplate. Thanks again, Reg _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
