Hello Andrew, > Did you intensively test that transformation? No, testing is still required. This is just a draft version.
> make sure that all basic solution components (statuses, primal and dual > values) are recovered correctly. Besides, can it be applied to interior > point and mip solutions? If I find two rows: lb1 <= sum(aj xj) <= ub1 lb2 <= sum(bj xj) <= ub2 such that aj * f = bj for all j with f = const I use row1->row->lb = -DBL_MAX, row1->row->ub = +DBL_MAX; npp_free_row(npp, row1->row); to free the rows, I create a new row row = npp_add_row(npp); such that max(lb2, lb1 * f) <= sum(bj xj) <= min(ub2, lb1 *f ) This should not change status, primal, dual values. But this needs testing. Best regards Xypron -------- Original-Nachricht -------- > Datum: Sat, 16 Oct 2010 01:12:50 +0400 > CC: Kevin Hunter <[email protected]>, Help Glpk <[email protected]> > Betreff: Re: [Help-glpk] Preprocessing > Hi Xypron, > > > I implemented an elimination of linear dependent rows in appended > > glpnpp06.c. > > > > This cuts the solution time for Kevin's problem down from several > > hours to 9 minutes. > > Great! Did you intensively test that transformation? It is important to > make sure that all basic solution components (statuses, primal and dual > values) are recovered correctly. Besides, can it be applied to interior > point and mip solutions? > > > Andrew Makhorin > > -- Neu: GMX De-Mail - Einfach wie E-Mail, sicher wie ein Brief! Jetzt De-Mail-Adresse reservieren: http://portal.gmx.net/de/go/demail _______________________________________________ Help-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-glpk
