[Fwd: Potential Bug Inquiry of GLPK]

[Andrew Makhorin]

-------- Forwarded Message --------

Date: Thu, 30 Jan 2025 02:04:36 +0000

Subject: Potential Bug Inquiry of GLPK

To: bug-glpk@gnu.org <bug-glpk@gnu.org>

From: Xintong Zhou <xintong.zhou1@uwaterloo.ca>

Hi,

 

I am using the latest version of GLPK to solve the attached MIP problem (seed.mps), and I am getting the following result:

 

Solver: GLPK_CMD

Status: Optimal

Objective: 4450.011933000001

x0 = 18, x1 = -24, x2 = -37, x3 = 9, x4 = -3, x5 = -48, x6 = 16, x7 = 9, x8 = -13.3293, x9 = 23.8585

 

While all the other solvers I have tried (including CBC, SCIP, HiGHS and Gurobi) return the same result as following:

 

Solver: CBC, SCIP, HiGHS, Gurobi

Status: Optimal

Objective: 4485.181539630002

x0 = 18, x1 = -24, x2 = -37, x3 = 9, x4 = -4, x5 = -48, x6 = 16, x7 = 9, x8 = -13.575019, x9 = 23.694121

 

Is this result expected for GLPK? I'm not sure if this difference of the answer is due to a different algorithm used by GLPK or it’s an implementation issue. Any response or suggestions are appreciated!

 

Thanks for your time!

 

Best wishes,

Xintong Zhou

Cheriton School of Computer Science

University of Waterloo

 

 

seed.mps
Description: seed.mps