Hi Chris, > > I did some testing with this version of dual simplex: I tried several > problems from miplib 2010, including some that had trouble with the > previous version and it seems to be a big improvement. The only issue > I run into was with primal simplex, similar to the case that was > reported earlier [1]. >
Thank you for testing. I don't know why I missed this common case when all objective coefficients are zero, and it is unclear how the dual solver could solve such instances at all, because in this case every dual step is degenerate until a dual feasible ray is found. A similar situation (i.e. for primal conic constraints Ax = 0, x >= 0) may happen in the primal simplex solver, though such instances are rarely appear in practice. Best regards, Andrew Makhorin _______________________________________________ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
