Hello Marc ------------------------------------------------------------ To: "[email protected]" <[email protected]> Subject: [Help-glpk] not retrieving integer solutions Message-ID: <04B026E012A010408111AFE9C67000A12319D36CF8@owgusdfwmbx03> From: "Meketon, Marc" <[email protected]> Date: Thu, 12 Jul 2012 17:14:39 -0500 ------------------------------------------------------------
> I am solving a small integer program (37 rows and 29 > columns) using the C# interface from > http://yoyovicks.blog.free.fr/ > > I've tested the code on quite a few datasets and it > worked fine. But today I changed some objective > function coefficients (just changed the sign of them), > and for one particular problem I'm retrieving > non-integer results despite the fact that an integer > optimal was found. > > [snip: code and results] > > Would anyone have a guess why the output is non-integer > despite solving to integer optimality and > double-checking that these variables are integer? > > BTW, when I write the problem out to GLPK format, and > solve it using glpsol, the output is fully integer. Please see: http://en.wikibooks.org/wiki/GLPK/Troubleshooting#Continuous_solution_to_mixed-integer_problem Could a be a bug in the C# wrapper or your use of the wrong calls? (Given C# supports polymorphism, could this wrapper not be written to proved the correct recovery using a generic interface?) Robbie --- Robbie Morrison PhD student -- policy-oriented energy system simulation Institute for Energy Engineering (IET) Technical University of Berlin (TU-Berlin), Germany University email (redirected) : [email protected] Webmail (preferred) : [email protected] [from Webmail client] _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
