<br><font size=2 face="sans-serif">Jean-Paul:</font>
<br><font size=2 face="sans-serif"><br>
If this is still an issue, can you post it in the Cgl bug tracking facility?
https://projects.coin-or.org/Cgl/report. The Project Manager
for CglTwomir is Oktay Gunluk. </font>
<br>
<br><font size=2 face="sans-serif">thanks,</font>
<br><font size=2 face="sans-serif">Robin</font>
<br>
<br><tt><font size=3>I have isolated a situation in which I believe CglTwomir
is returning invalid cuts. I have attached a test driver (driver.cpp),
a test input file (mas74.mps, from miplib2003), and the output trace I
obtain on our rather vanilla RedHat linux server.<br>
<br>
<br>
The "catch" is that I'm using CPLEX 11.2, and the OsiCpxSolverInterface.
Although this technically shouldn't matter, I suppose (the behavior also
occurs with other versions of CPLEX).<br>
<br>
A quick summary of the unexpected behavior:<br>
1) The LP relaxation for mas74 solves fine - relaxation
is around 10K. Validated with various other solvers.<br>
2) 3 two-mir cuts are found and successfully applied.<br>
3) Upon re-solve after cut addition, the LP relaxation
is something like 21K, which is far above the integer optimal of ~11K.
Obviously incorrect behavior.<br>
<br>
Any help is greatly appreciated - I am seeing similar behavior on a handful
of other test instances.<br>
</font></tt>
<br>
<br>
<br>
<br><font size=2 face="sans-serif"><br>
----------------------------------------------------------------------------------<br>
Robin Lougee-Heimer, PhD<br>
Program Manager, COIN-OR<br>
IBM TJ Watson Research Center<br>
1101 Kitchawan Road, Yorktown Heights, NY 10598<br>
ph: 914-945-3032 fax: 914-945-3434 <br>
robinlh@us.ibm.com<br>
http://www.coin-or.org<br>
<br>
</font>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td width=40%><font size=1 face="sans-serif"><b>"Watson, Jean-paul"
<jwatson@sandia.gov></b> </font>
<br><font size=1 face="sans-serif">Sent by: cgl-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">10/06/2009 11:21 PM</font>
<td width=59%>
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<td>
<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">"Matthew Saltzman" <mjs@clemson.edu></font>
<tr valign=top>
<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td><font size=1 face="sans-serif">"cgl@list.coin-or.org" <cgl@list.coin-or.org></font>
<tr valign=top>
<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">Re: [Cgl] Success!</font></table>
<br>
<table>
<tr valign=top>
<td>
<td></table>
<br></table>
<br>
<br>
<br><tt><font size=2>That was probably it - the total was around 80K bytes
(mas74 is largely than I thought). I've attached g'zipped versions of the
attachments.<br>
<br>
Jean-Paul<br>
<br>
--<br>
<br>
<br>
Dr. Jean-Paul Watson<br>
Discrete Math and Complex Systems Department<br>
Sandia National Laboratories<br>
P.O. Box 5800, MS 1318<br>
Albuquerque, NM 87185-1318<br>
(505) 845-8887<br>
jwatson@sandia.gov<br>
<br>
<br>
<br>
<br>
-----Original Message-----<br>
From: Matthew Saltzman [mailto:mjs@clemson.edu] <br>
Sent: Tuesday, October 06, 2009 8:48 PM<br>
To: Watson, Jean-paul<br>
Cc: cgl@list.coin-or.org<br>
Subject: Re: [Cgl] Success!<br>
<br>
How big are your attachments? They should work, but there's a 40K
limit<br>
on message body size.<br>
<br>
On Tue, 2009-10-06 at 20:33 -0600, Watson, Jean-paul wrote: <br>
> Sorry about the posting issues – I’m not sure why the attachments<br>
> didn’t come through. If someone is able to look at this bug, please<br>
> contact me (I’m not sure who is the CGL Czar) and I’ll forward them<br>
> along.<br>
> <br>
> Jean-Paul<br>
<br>
<br>
-- <br>
Matthew Saltzman<br>
<br>
Clemson University Math Sciences<br>
mjs AT clemson DOT edu<br>
http://www.math.clemson.edu/~mjs<br>
<br>
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Cgl@list.coin-or.org<br>
http://list.coin-or.org/mailman/listinfo/cgl<br>
</font></tt>
<br>