Re: [Help-glpk] GLPK and MIPLIB 2003 manna81.mps

[glpk xypron]

Hello Jen-Min,

the problem file can be found at 
http://miplib.zib.de/miplib2003/manna81.php

The optimum solution is described in
http://www.dei.unipd.it/~fisch/papers/lexGomory_cuts.pdf
as 
LP opt = -13297
MILP opt = -13164.

-13164 is the first integer solution found by GLPK (after 2 minutes on a rather 
slow Linux server) with a gap of 1 %.

This matches a report concerning the Dash optimizer
http://www.ima.umn.edu/2004-2005/W7.25-29.05/activities/Perregaard-Michael/cbranch.ppt
manna81: solved on root with no branching.

Could You, please, identify which is the termination criterion for COIN_OR, e.g 
does it simply stop if the gap is less then 1 %? Glpsol will only stop at a 
much smaller gap if You do not use the command line parameter --mipgap.

Which was the optimum found by COIN_OR?

Do You get the same result on Windows: MILP opt = -13164 for gap = 1 %?

Best regards

Xypron



-------- Original-Nachricht --------
> Datum: Wed, 28 May 2008 06:45:57 -0700
> Von: "Cheng,Jen-Min" <address@hidden>
> An: address@hidden
> Betreff: [Help-glpk] GLPK and MIPLIB 2003 manna81.mps

> 
> I generated glpsol.exe 4.2.8 using Microsoft Visual Studio 2005.  It did
> not stop after over 10 hours when manna81.mps of MIPLIB 2003 was being
> solved.  However COIN_OR could solve manna81.mps in less than 10
> seconds.  
> 
> Will any please tell me what happened.   Thanks.
> 
> 
> 
> 
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> Help-glpk mailing list
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