[Bug-glpk] [Fwd: Bug in GLPK (Maybe)]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Oliver Czibula <address@hidden>
To: address@hidden
Subject: Bug in GLPK (Maybe)
Date: Fri, 31 Aug 2012 11:56:20 +1000

Hello,


Please see attached file.


I have defined a mixed integer program in Lingo and solved it. Lingo
reports that it finds an optimal solution. I have used Excel to verify
that the solution is, in fact, feasible.
I then used Lingo to export the model as an MPS file which GLPK can read
and solve.


When I ask GLPSOL to solve the model in the MPS file, GLPSOL tells me
that there exists no feasible solution.
I'm not sure if this bug is in GLPK or if Lingo has exported a bad MPS
file, however I have been using the MPS export from Lingo quite a lot
and haven't had any problems up until now!


I am using GLPK Lab for Windows, running GLPSOL v4.43


I look forward to hearing back from you.
Regards,


-- Oliver Czibula

BugSomewhere.zip
Description: Zip archive