On 01/16/2017 11:59 PM, Andrew Makhorin wrote: > >> the interesting thing about Matheu's example is that the infeasability >> is constantly increasing over multiple orders of magnitude. > > I'm unable to reproduce the effect. Glpsol with default options has no > problem on solving Mathieu's example. If --norelax option is specified, > the primal simplex falls into infinite loop, but this might be expected, > because Harris' ratio test (that is, --relax option used by default) > decreases the number of degenerate steps and thus prevents cycling in > many cases. If the primal simplex fails, I'd recommend using --dual and > --flip options. > > > Andrew Makhorin > >
With GLPK 4.61 on Linux 64bit and --norelax it is not simply an infinite loop. The infeasibility increases constantly as shown in the log below. glpsol -m GLP_buggy_6d21.mod --norelax * 500: obj = 1.262121212e+04 inf = 4.004e-15 (2) * 1000: obj = 1.262121212e+04 inf = 1.052e-14 (2) * 1500: obj = 1.262121212e+04 inf = 1.703e-14 (2) * 2000: obj = 1.262121212e+04 inf = 2.355e-14 (2) * 2500: obj = 1.262121212e+04 inf = 3.006e-14 (2) * 3000: obj = 1.262121212e+04 inf = 3.658e-14 (2) * 3500: obj = 1.262121212e+04 inf = 4.309e-14 (2) * 4000: obj = 1.262121212e+04 inf = 4.961e-14 (2) * 4500: obj = 1.262121212e+04 inf = 5.612e-14 (2) * 5000: obj = 1.262121212e+04 inf = 6.264e-14 (2) * 5500: obj = 1.262121212e+04 inf = 6.915e-14 (2) * 6000: obj = 1.262121212e+04 inf = 7.567e-14 (2) * 6500: obj = 1.262121212e+04 inf = 8.218e-14 (2) * 7000: obj = 1.262121212e+04 inf = 8.870e-14 (2) * 7500: obj = 1.262121212e+04 inf = 9.521e-14 (2) * 8000: obj = 1.262121212e+04 inf = 1.017e-13 (2) ... *177000: obj = 1.262121211e+04 inf = 2.304e-12 (2) *177500: obj = 1.262121211e+04 inf = 2.310e-12 (2) *178000: obj = 1.262121211e+04 inf = 2.317e-12 (2) *178500: obj = 1.262121211e+04 inf = 2.323e-12 (2) *179000: obj = 1.262121211e+04 inf = 2.330e-12 (2) ... *826000: obj = 1.262121208e+04 inf = 1.076e-11 (2) *826500: obj = 1.262121208e+04 inf = 1.077e-11 (2) *827000: obj = 1.262121208e+04 inf = 1.077e-11 (2) *827500: obj = 1.262121208e+04 inf = 1.078e-11 (2) *828000: obj = 1.262121208e+04 inf = 1.079e-11 (2) ... *10719000: obj = 1.262121156e+04 inf = 1.397e-10 (2) *10719500: obj = 1.262121156e+04 inf = 1.397e-10 (2) *10720000: obj = 1.262121156e+04 inf = 1.397e-10 (2) *10720500: obj = 1.262121156e+04 inf = 1.397e-10 (2) *10721000: obj = 1.262121156e+04 inf = 1.397e-10 (2) _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
