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<div class="moz-cite-prefix">Thomas,<br>
<br>
As I am unable to justify it and as removing made a slight
improvement on some very limited tests, I have removed the 500 in
Cgl/0.57 which is what cbc uses.<br>
<br>
John<br>
<br>
On 20/12/12 19:55, Thomas Schoenemann wrote:<br>
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<blockquote
cite="mid:1356033311.9955.YahooMailNeo@web172304.mail.ir2.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff; font-family:times
new roman, new york, times, serif;font-size:12pt">Hi all,<br>
<br>
my application of Cbc (where I added a GomoryCut generator) was
producing abnormally large cuts at the root node, although I had
set a limit. So I looked into the code and found this passage
(line 679 of GomoryCut.cpp):<br>
<br>
<br>
limit = limitAtRoot_;<br>
if (!info.pass) {<br>
tolerance1=1.0;<br>
tolerance2=1.0e-2;<br>
tolerance3=1.0e-6;<br>
tolerance6=1.0e-7;<br>
tolerance9=1.0e-5;<br>
if (!limit||limit>=500) <----!!!!!!!!!!!!!<br>
limit=numberColumns;<br>
} else {<br>
<br>
<br>
It appears that Cbc does not set info.pass (whatever that
signifies) and in this case a limit of 500 or larger is simply
ignored. <br>
<br>
I was wondering if there is a plausible reason for this. At the
very least I think this behavior should be documented in the
text on setLimitAtRoot(). Personally, I'd prefer if the part
"||limit >= 500" was removed, it does not make sense to me.<br>
<br>
I have a recent version of Cbc, checked out via svn (maybe there
is already a repository for 2.8?):<br>
<br>
URL: <a class="moz-txt-link-freetext" href="https://projects.coin-or.org/svn/Cbc/stable/2.7">https://projects.coin-or.org/svn/Cbc/stable/2.7</a><br>
Basis des Projektarchivs: <a class="moz-txt-link-freetext" href="https://projects.coin-or.org/svn/Cbc">https://projects.coin-or.org/svn/Cbc</a><br>
UUID des Projektarchivs: 6f23a84d-0c12-0410-9f0c-b73a89ba9ce0<br>
Revision: 1833<br>
Knotentyp: Verzeichnis<br>
Plan: normal<br>
Letzter Autor: stefan<br>
Letzte geänderte Rev: 1833<br>
Letztes Änderungsdatum: 2012-12-04 11:21:49 +0100 (Di, 04. Dez
2012)<br>
<br>
<br>
If you need my help, let me know.<br>
<br>
Best regards,<br>
Thomas Schoenemann<br>
<div><br>
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