Hello Diego, in your log from GLPK 4.60 we see the following lines:
DEBUG JCspGlpkCallback - GLPKConstants.GLP_IHEUR Solution found by heuristic: 2840 So if you did not call glp_ios_heur_sol, it must be round_heur that found the solution. You could set iocp->sr_round = GLP_OFF to switch off this heuristic. In Java you do this by calling glp_iocp iocp; iocp = new glp_iocp(); GLPK.glp_init_iocp(iocp); iocp.setSr_heur(GLPKConstants.GLP_OFF); @Andrew Could you, please, comment on how lazy constraints can be used together with sr_round = GLP_ON. I could not find anything in doc/glpk.pdf on the interaction between the two. Best regards Heinrich Schuchardt On 11/16/2016 12:12 PM, Andrew Makhorin wrote: -------- Forwarded Message -------- > To: [email protected] > Cc: [email protected], [email protected] > Subject: Re: Aw: [Bug-glpk] [Fwd: Problem updating from version 4_47 to > 4_60] > Date: Wed, 16 Nov 2016 11:14:14 +0100 > > Thank you for your answer but i think is not a problem of my callback > method because is the same in both cases. > > I am using a branch-and-cut method to solve MIP problems. > > I start with a simple LP problem, it doesn´t contain all the > constraints(rows) that i need but i add them step by step when the > glp_intopt(prob,iocp)routine, calls the callback method with the reason > ROWGEN. > In that moment i check if the current LP solution solve my needs and if > not, i add some new constraints to the initial problem (prob). and the > solver continues with the branch-and-cut algorithm. > > In version 4_47 it runs ok and the routine navigates the tree adding new > rows when i need it, and finishes with a MIP solution that solve all of > my needs. > > In version 4_60 the routine finishes before i expected it with a MIP > solution that doesn't solve all of my needs. > > In the logs that i attached, you can see all the calls that > glp_intopt(prob,iocp)does to my callback method and the reason > (GLP_ISELECT,GLP_IPREPRO,GLP_IROWGEN,......) > > Using version 4_60 just calls twice to my callback method with the > reason rowgen. It seems that it doesn't navigate the tree correctly. > > Has any change in the branch-and-cut algorithm? > > Thank you in advance and excuse me if i am wrong. > > > > > > De: "Heinrich Schuchardt" <[email protected]> > Para: "Andrew Makhorin" <[email protected]>, "Bug Glpk" > <[email protected]>, [email protected] > Fecha: 02/11/2016 15:23 > Asunto: Aw: [Bug-glpk] [Fwd: Problem updating from version 4_47 > to 4_60] > > ________________________________________________________________________ > > > > Hello Diego, > > the 4.60 log shows that your Java code supplied a solution with a better > value than the 4.47 solution. > > Please, check your callback method. > > Best regards > > Heinrich > _______________________________________________ Bug-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/bug-glpk
