glp_read_lp can be one of the causes: The order of the variables can affect the number of simplex iterations - the index of the variable can be used to break ties in selecting the next variable to enter the base.
But it appears that this is a more complex issue: the processing time increased more than one time (a lot) as new GLPK versions appeared... On Tue, Mar 12, 2013 at 9:05 PM, Patrik Dufresne <[email protected]> wrote: > Hi, > > May someone give me an explanation about why the same problem run with > glpk 4.38 is faster then glpk 4.47 ? > > GLPK Version > > Iteration > > Time used > > 4.37 > > 6507 > > 3.6 secs > > 4.38 > > 6496 > > 5.5 secs > > 4.39 > > 23708 > > 22.1 secs > > 4.40 > > 23708 > > 22.1 secs > > 4.41 > > 23708 > > 23.6 secs > > 4.42 > > 45540 > > 64.6 secs > > 4.43 > > 45540 > > 64.4 secs > > 4.44 > > 45540 > > 60.7 secs > > 4.45 > > 45540 > > 60.3 secs > > 4.46 > > 45540 > > 61.5 secs > > 4.47 > > 45540 > > 61.0 secs > > Run with > ./glpsol --intopt --fpump --cpxlp min-all-swappable-task1 > > See my dropbox for all the results and the problem file > https://www.dropbox.com/sh/ja2myngas5lorow/oUTkkFxW5N/glpk-438-vs439 > > Looking at the change log, the only related modification I see that may > impact the number of iteration if the reimplementation of glp_read_lp(). > Thanks for your comments. > > Patrik Dufresne > > _______________________________________________ > Help-glpk mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/help-glpk > > -- ============================================================= Haroldo Gambini Santos Computing Department Universidade Federal de Ouro Preto - UFOP email: haroldo [at ] iceb.ufop.br home/research page: www.decom.ufop.br/haroldo
_______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
