> I noticed a small inconsistency with working with lpx_set_mat_row(). > If you inserted a couple of columns the output of the columns > lpx_write_cpxlp() are reversed. Clearly this is not bug, but sometimes > it confuses me. Should also be valid in combination of lpx_add_row() > and lpx_set_mat_col(). Can you check?
The order of column indices reported by lpx_get_mat_row is unpredictable, i.e. the indices may follow in arbitrary order, not necessarily in the same order they were specified on a call to lpx_set_mat_row. (This is normal in sparse matrix computations.) Lpx_write_cpxlp writes columns as they reported by lpx_get_mat_row, so the column ordering may be altered. In principle, you can call the routine lpx_order_matrix(lp) before a call to lpx_write_cpxlp. It rearranges the row and column lists, in which case column indices reported by lpx_get_mat_row will follow in ascending order. _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
