Hello Andrew, The dual simplex method, techniques for a fast and stable implementation / Achim Koberstein Paderborn, Univ., Diss., 2005 Dissertation (PhD)
describes on page 89 the possibility of numerical cycling due to the Harris test: http://digital.ub.uni-paderborn.de/hs/content/pageview/1508326 Wouldn't it be safer to change the default ratio test to --norelax. See https://pdfs.semanticscholar.org/2472/518346d657b8126d8ebe8657e2626dff5ef9.pdf for ideas how to avoid cycling. Best regards Heinrich On 01/11/2017 08:06 PM, Mathieu Dutour wrote: > Thanks a lot! > > Mathieu > > On 11 January 2017 at 19:52, Heinrich Schuchardt <[email protected] > <mailto:[email protected]>> wrote: > > glpsol -m GLP_buggy.mod --norelax > runs fine. > > glpsol -m GLP_buggy.mod > loops for ever. > > I tested with the GLPK 4.61 prerelease. > > Best regards > > Heinrich Schuchardt > > On 01/11/2017 12:14 PM, Mathieu Dutour wrote: > > Dear all, > > > > I obtained some infinite cycles when running the > > glpsol standalone solver on some instances. > > See two files in attachment. > > > > I had the instances of this phenomenon with > > version 4.57 which disappeared with version 4.60. > > > > Is there a way to avoid this phenomenon? I mean > > it is fully acceptable to me to have GLPK report > > that he cannot solve an instance due to numerical > > instability. What is not acceptable is the infinite > > cycles. > > > > Thanks in advance for any help. > > Sincerely, > > > > Mathieu > > > > > > _______________________________________________ > > Help-glpk mailing list > > [email protected] <mailto:[email protected]> > > https://lists.gnu.org/mailman/listinfo/help-glpk > <https://lists.gnu.org/mailman/listinfo/help-glpk> > > > > _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
