<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
tt
{mso-style-priority:99;
font-family:"Courier New";}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.Section1
{page:Section1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-US link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hi Robin,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>It is still a bug; I’ll post it now.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Jean-Paul<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Robin Lougee-Heimer
[mailto:robinlh@us.ibm.com] <br>
<b>Sent:</b> Thursday, December 10, 2009 12:31 PM<br>
<b>To:</b> Watson, Jean-paul<br>
<b>Cc:</b> cgl@list.coin-or.org; gunluk@us.ibm.com<br>
<b>Subject:</b> CglTwomir issue (Re: [Cgl] Success!)<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><br>
<span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Jean-Paul:</span>
<br>
<span style='font-size:10.0pt;font-family:"Arial","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. </span> <br>
<br>
<span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>thanks,</span> <br>
<span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Robin</span> <br>
<br>
<tt>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.</tt><span style='font-family:"Courier New"'><br>
<br>
<br>
<tt>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).</tt><br>
<br>
<tt>A quick summary of the unexpected behavior:</tt><br>
<tt>1) The LP relaxation for mas74 solves fine - relaxation
is around 10K. Validated with various other solvers.</tt><br>
<tt>2) 3 two-mir cuts are found and successfully applied.</tt><br>
<tt>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.</tt><br>
<br>
<tt>Any help is greatly appreciated - I am seeing similar behavior on a handful
of other test instances.</tt><br>
</span><br>
<br>
<br>
<br>
<span style='font-size:10.0pt;font-family:"Arial","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>
</span><br>
<br>
<o:p></o:p></p>
<table class=MsoNormalTable border=0 cellpadding=0 width="100%"
style='width:100.0%'>
<tr>
<td width="40%" valign=top style='width:40.0%;padding:.75pt .75pt .75pt .75pt'>
<p class=MsoNormal><b><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>"Watson,
Jean-paul" <jwatson@sandia.gov></span></b><span style='font-size:
7.5pt;font-family:"Arial","sans-serif"'> </span><br>
<span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>Sent by:
cgl-bounces@list.coin-or.org</span> <o:p></o:p></p>
<p><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>10/06/2009
11:21 PM</span> <o:p></o:p></p>
</td>
<td width="59%" valign=top style='width:59.0%;padding:.75pt .75pt .75pt .75pt'>
<table class=MsoNormalTable border=0 cellpadding=0 width="100%"
style='width:100.0%'>
<tr>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='font-size:7.5pt;font-family:"Arial","sans-serif"'>To</span><o:p></o:p></p>
</td>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>"Matthew
Saltzman" <mjs@clemson.edu></span> <o:p></o:p></p>
</td>
</tr>
<tr>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='font-size:7.5pt;font-family:"Arial","sans-serif"'>cc</span><o:p></o:p></p>
</td>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>"cgl@list.coin-or.org"
<cgl@list.coin-or.org></span> <o:p></o:p></p>
</td>
</tr>
<tr>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='font-size:7.5pt;font-family:"Arial","sans-serif"'>Subject</span><o:p></o:p></p>
</td>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'>Re:
[Cgl] Success!</span><o:p></o:p></p>
</td>
</tr>
</table>
<p class=MsoNormal><o:p> </o:p></p>
<table class=MsoNormalTable border=0 cellpadding=0>
<tr>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'></td>
<td valign=top style='padding:.75pt .75pt .75pt .75pt'></td>
</tr>
</table>
</td>
</tr>
</table>
<p class=MsoNormal style='margin-bottom:12.0pt'><br>
<br>
<br>
<tt><span style='font-size:10.0pt'>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.</span></tt><span style='font-size:10.0pt;font-family:"Courier New"'><br>
<br>
<tt>Jean-Paul</tt><br>
<br>
<tt>--</tt><br>
<br>
<br>
<tt>Dr. Jean-Paul Watson</tt><br>
<tt>Discrete Math and Complex Systems Department</tt><br>
<tt>Sandia National Laboratories</tt><br>
<tt>P.O. Box 5800, MS 1318</tt><br>
<tt>Albuquerque, NM 87185-1318</tt><br>
<tt>(505) 845-8887</tt><br>
<tt>jwatson@sandia.gov</tt><br>
<br>
<br>
<br>
<br>
<tt>-----Original Message-----</tt><br>
<tt>From: Matthew Saltzman [mailto:mjs@clemson.edu] </tt><br>
<tt>Sent: Tuesday, October 06, 2009 8:48 PM</tt><br>
<tt>To: Watson, Jean-paul</tt><br>
<tt>Cc: cgl@list.coin-or.org</tt><br>
<tt>Subject: Re: [Cgl] Success!</tt><br>
<br>
<tt>How big are your attachments? They should work, but there's a 40K
limit</tt><br>
<tt>on message body size.</tt><br>
<br>
<tt>On Tue, 2009-10-06 at 20:33 -0600, Watson, Jean-paul wrote: </tt><br>
<tt>> Sorry about the posting issues – I’m not sure why the
attachments</tt><br>
<tt>> didn’t come through. If someone is able to look at this bug, please</tt><br>
<tt>> contact me (I’m not sure who is the CGL Czar) and I’ll
forward them</tt><br>
<tt>> along.</tt><br>
<tt>> </tt><br>
<tt>> Jean-Paul</tt><br>
<br>
<br>
<tt>-- </tt><br>
<tt> Matthew Saltzman</tt><br>
<br>
<tt>Clemson University Math Sciences</tt><br>
<tt>mjs AT clemson DOT edu</tt><br>
<tt>http://www.math.clemson.edu/~mjs</tt><br>
<br>
<tt>_______________________________________________</tt><br>
<tt>Cgl mailing list</tt><br>
<tt>Cgl@list.coin-or.org</tt><br>
<tt>http://list.coin-or.org/mailman/listinfo/cgl</tt></span><o:p></o:p></p>
</div>
</body>
</html>