[Help-glpk] [Fwd: glpsol not converging]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Narendra Devta-Prasanna <address@hidden>
To: address@hidden
Subject: glpsol not converging
Date: Thu, 26 Jul 2012 12:23:43 -0700

Hi,

I am relatively new to using ILP solvers and do not understand all the
underlying mathematics. I am using glpsol to solve a routing problem.
For most instance of the problem, I get a solution within minutes. But
in one case, when the size of the problem is bigger, it is not
converging after running for more than 3 days and 10 million iterations.
After about 12500th iteration, the objective function value does not
improve but the tool does not ever stop.

I have tried different options such as --first, --dfs, --pcost etc but
nothing seems to help. I have also included "--mipgap 0.1" and also
tried with other values but still does not help. Is there a way I can
tell the tool to stop after a certain number of iterations and print the
most optimal solution identified so far and make the results available
through printf commands etc.

I have looked all over the web for any further clues to solving this. I
really appreciate it if the experts on this mailing list can help with
how to address this issue.

Thanks and Regards,
-Narendra