> I am writing to report what looks like a bug in glpk-4.39, that, > surprisingly, is not there in glpk-4.26.
> Below, I first describe the problem, and its output when run with > glpk-4.39 on a pc running fedora-11. It is solved incorrectly by > glpk-4.39. Then, I will give the output of glpk-4.26, which solves it > correctly Would you please let me know if there is a bug, or if I am doing > something wrong. I do however know that I am doing the same thing in > invoking glpk-4.39 and glpk-4.26. The error appears due to very small constraint coefficient in your model (of order 1e-32). Glpk 4.26 successfully solves the model, because by default it performs only equilibration scaling while glpk 4.39 also performs geometric mean scaling to minimize the ratio max|aij|/min|aij| that in your case does not help. You need to either disable automatic scaling with the option '--noscale' or, that is much better, remove tiny constraint coefficients from the model. _______________________________________________ Bug-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-glpk
