-------- Forwarded Message -------- From: Robert Peharz <[email protected]> To: [email protected] Subject: Bug report GLPK Version 4.43 Date: Tue, 16 Aug 2011 19:15:24 +0200
Hi, I think there is a bug concerning the MILP solver in GLPK version 4.43. I deactivated the MILP presolver, and explicitly provided a valid basis by running the simplex method first, followed by glp_intopt: retSIMP = glp_simplex(lp, &simplexParams); retMILP = glp_intopt(lp, &milpParams); Occasionally it happens that the MILP solver does not need to branch (i.e. the MILP callback function is never called with glp_ios_reason(tree) == GLP_IBRANCH), but an integer solution is found merely using (Gomory) cutting planes. In these cases, glp_intopt does not return the integer solution, but the initial, relaxed solution as found by the simplex method. I am not sure, if this also happens when the MILP presolver is activated. Best regards, Robert Peharz _______________________________________________ Bug-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/bug-glpk
