[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Bug-glpk] [Fwd: Bug report GLPK Version 4.43]
From: |
Andrew Makhorin |
Subject: |
[Bug-glpk] [Fwd: Bug report GLPK Version 4.43] |
Date: |
Wed, 17 Aug 2011 00:39:16 +0400 |
-------- Forwarded Message --------
From: Robert Peharz <address@hidden>
To: address@hidden
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] [Fwd: Bug report GLPK Version 4.43],
Andrew Makhorin <=