<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">Giacomo,<br>
<br>
<br>
I tried swapping GMI for Gomory and the same thing happened.<br>
<br>
It just seems to be errors building up, especially with general
integer variables.<br>
<br>
John<br>
On 04/03/15 13:30, Giacomo Nannicini wrote:<br>
</div>
<blockquote
cite="mid:CAFy=0d17oyKA+v96m1_wWOrzKWAy3DhBYvzU2EtHx21gF4k8Lg@mail.gmail.com"
type="cite">
<div dir="ltr">Hi Yves,
<div>did you try the CglGMI generator? You may want to see if
using CglGMI instead of CglGomory helps. In my experience, the
cuts from CglGMI are less prone to numerical errors: in fact,
that's the reason the generator was developed. See <a
moz-do-not-send="true"
href="http://link.springer.com/article/10.1007%2Fs12532-013-0057-4">http://link.springer.com/article/10.1007%2Fs12532-013-0057-4</a></div>
<div><br>
</div>
<div>Giacomo</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Mar 4, 2015 at 7:06 PM, Yves
Touchard <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:ytouch@dxo.com" target="_blank">ytouch@dxo.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<small>Hello,<br>
<br>
Switching off the twomir cuts makes also the problem
feasible.<br>
<br>
Cheers<span class="HOEnZb"><font color="#888888"><br>
<br>
Yves<br>
</font></span></small><br>
<div><span class=""><br>
-------- Message transféré --------
<table border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<th align="RIGHT" nowrap="nowrap"
valign="BASELINE">Sujet : </th>
<td>Gomory or not Gomory, that is the question.</td>
</tr>
<tr>
<th align="RIGHT" nowrap="nowrap"
valign="BASELINE">Date : </th>
<td>Tue, 03 Mar 2015 20:03:03 +0100</td>
</tr>
<tr>
<th align="RIGHT" nowrap="nowrap"
valign="BASELINE">De : </th>
<td>Yves Touchard <a moz-do-not-send="true"
href="mailto:yves.touchard@sfr.fr"
target="_blank">
<yves.touchard@sfr.fr></a></td>
</tr>
<tr>
<th align="RIGHT" nowrap="nowrap"
valign="BASELINE">Pour : </th>
<td><a moz-do-not-send="true"
href="mailto:cbc@list.coin-or.org"
target="_blank">cbc@list.coin-or.org</a></td>
</tr>
</tbody>
</table>
<br>
<br>
</span>
<div>
<div class="h5"><font size="-1">Hello,<br>
<br>
You will find here (</font><font size="-1"><font
size="-1"><a moz-do-not-send="true"
href="https://www.dropbox.com/s/ayo93hi4togpc9m/noGom.lp?dl=0"
target="_blank">https://www.dropbox.com/s/ayo93hi4togpc9m/noGom.lp?dl=0</a></font>)
a constraint file for which cbc founds a solution
when Gomory cuts are removed or for specific
cutlength values.<br>
<br>
In other words, the following command leads to an
infeasible problem:<br>
<i>/soft/cbc-trunk-2149/bin/cbc noGom.lp branch
printingOptions normal solution noGom.sol</i><br>
<br>
and with the following commands, cbc claims that
there is a solution:<br>
</font><font size="-1"><font size="-1"><i>/soft/cbc-trunk-2149/bin/cbc
noGom.lp gomory off branch printingOptions
normal solution noGom.sol</i></font><br>
</font><font size="-1"><font size="-1"><i>/soft/cbc-trunk-2149/bin/cbc
noGom.lp cutlength xx branch printingOptions
normal solution noGom.sol</i></font> (with xx
equal to -1, 0, 10, 20... and different from
30...)<br>
<br>
Since our problems are dynamically generated, it
is very painful to try to solve them with
different options, hoping that the right set is in
the list.<br>
<br>
</font><font size="-1">So, is there a way to find
this set of options.<br>
Or could you explain what are the rows that are
difficult for cbc.<br>
And, does the change of the continuous variables
into integer variables help? (for our problems, it
makes sense).<br>
<br>
Thanks and regards<br>
<br>
Yves<br>
</font><br>
</div>
</div>
</div>
<br>
<span class="">
<br>
<font color="Black" face="Arial">------------------------------------------------------------------------------<br>
This message and any attachments (the "message") are
confidential and intended solely for the addressee(s).
Any unauthorized use or dissemination is prohibited.
E-mails are susceptible to alteration. Neither DxO
Labs nor any of its subsidiaries or affiliates shall
be liable for the message if altered, changed or
falsified.<br>
Ce message et toutes les pièces jointes (ci-après le
"message") sont confidentiels et établis à l'intention
exclusive de ses destinataires. Toute utilisation ou
diffusion non autorisé est interdite. Tout message
électronique est susceptible d'altération. DxO Labs et
ses filiales déclinent toute responsabilité au titre
de ce message s'il a été altéré, modifié ou falsifié.<br>
</font>
</span></div>
<br>
_______________________________________________<br>
Cbc mailing list<br>
<a moz-do-not-send="true" href="mailto:Cbc@list.coin-or.org">Cbc@list.coin-or.org</a><br>
<a moz-do-not-send="true"
href="http://list.coin-or.org/mailman/listinfo/cbc"
target="_blank">http://list.coin-or.org/mailman/listinfo/cbc</a><br>
<br>
</blockquote>
</div>
<br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Cbc mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Cbc@list.coin-or.org">Cbc@list.coin-or.org</a>
<a class="moz-txt-link-freetext" href="http://list.coin-or.org/mailman/listinfo/cbc">http://list.coin-or.org/mailman/listinfo/cbc</a>
</pre>
</blockquote>
<br>
</body>
</html>