<br><font size=2 face="sans-serif">Philip,</font>
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<br><font size=2 face="sans-serif">If you can send me the model I will
look at it and try and document the way I tuned it. I might include
such an example in my tutorial at DIMACS workshop if people think that
a good idea.</font>
<br>
<br><font size=2 face="sans-serif">John Forrest</font>
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<td width=40%><font size=1 face="sans-serif"><b>hpwalton@comcast.net</b>
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<br><font size=1 face="sans-serif">Sent by: coin-discuss-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">06/01/2006 12:29 AM</font>
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<div align=center><font size=1 face="sans-serif">Please respond to<br>
Discussions about open source software for Operations Research
<coin-discuss@list.coin-or.org></font></div></table>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">coin-discuss@list.coin-or.org</font>
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<div align=right><font size=1 face="sans-serif">cc</font></div>
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<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">[Coin-discuss] Suggestions on how to
go about tuning?</font></table>
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<br><font size=3>Is there doc anywhere on suggestions for tuning CBC/Clp?
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<br><font size=3> </font>
<br><font size=3>I'm having a performance issue with a specific instance
of data. Other instances of the same data run very quickly...(a few
seconds), and this is running in terms of hours.</font>
<br><font size=3> </font>
<br><font size=3>I'm thinking CBC just gets off on the wrong foot. I'm
able to solve it with another open source solver very rapidly (in the "few
minutes" range). </font>
<br><font size=3> </font>
<br><font size=3>I was hoping I could learn enough on my own, but at this
point I'm not really sure the most effective way to go about it. I'm
not looking for someone to do the thinkin' for me..more lookin' for some
guidance on CBC specifically.</font>
<br><font size=3> </font>
<br><font size=3>It is (roughly) a Hamiltonian Cycle problem...I've indicated
some SOS type 1 constraints and that helped get an answer fast, but the
answer isn't all that good.</font>
<br><font size=3> </font>
<br><font size=3>It's a minimization problem, the optimal solution is 2.1,
the first integer answer CBC finds is 3.6, and the "lower bound"
is 1. the cost/weights are non-negative small decimals (ranging from
zero to 2.5).</font>
<br><font size=3> </font>
<br><font size=3>The lower bound doesn't start coming up for quite a while...so
it spends a lot of time exploring nodes which are not fruitful.</font>
<br><font size=3> </font>
<br><font size=3>Any suggestions are welcome. I've seen at least
one other request in the archives for tuning paramters...</font>
<br><font size=3> </font>
<br><font size=3>Thanks,</font>
<br><font size=3>Philip</font><tt><font size=2>_______________________________________________<br>
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