<br><font size=2 face="sans-serif">Christian,</font>
<br>
<br><font size=2 face="sans-serif">Very difficult to answer. I have
one integer model which really annoys me as a tiny change to code
or optimization level can change time for complete search from 10 seconds
to nearly an hour. How many nodes does each take? If yours
takes many more then it is not memory - but "bad luck". If
so try changing a few parameters e.g. to do with strong branching to see
if you can make it faster. It is also worth seeing how much objective
moved at root due to cuts in case one cut generator had a better starting
point.</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>WoelliUSM@aol.com</b> </font>
<br><font size=1 face="sans-serif">Sent by: coin-discuss-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">10/02/2006 02:18 PM</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] How do I "speed
up" CBC?</font></table>
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<br><font size=2 face="Arial">Dear all,</font>
<br><font size=2 face="Arial"> </font>
<br><font size=2 face="Arial">I got a question concerning the performance
of the CBC-solver. I use FlopC++ in combination with CBC under Linux and
my professor GAMS with CBC under Windows. We use the same test instances,
but there are dramatic differences of the performances of CBC. </font>
<br><font size=2 face="Arial">After the generation of a test instance (does
not matter whether FlopC++ or GAMS), it takes only seconds for him to solve
the problem. I need much, much, much more time. </font>
<br><font size=2 face="Arial">One test instance has about 660000 non-zeros
in the coefficient matrix. It takes about 250 seconds to solve on his computer,
and I get the message "KILLED"! </font>
<br><font size=2 face="Arial">Where can be a software difference? Are there
different starting parameters? We both did not change CBC after downloading,
we just connected them to GAMS/FlopC++. </font>
<br><font size=2 face="Arial">There is only one difference of the computers
we use. We both have a 3GHZ Inter Pentium 4, but I just got 1GB RAM, whereas
he got 4GB RAM!</font>
<br><font size=2 face="Arial">Is that the answer to the question above?</font>
<br><font size=2 face="Arial"> </font>
<br><font size=2 face="Arial">Thanks in advance,</font>
<br><font size=2 face="Arial"> </font>
<br><font size=2 face="Arial">Christian</font><tt><font size=2>_______________________________________________<br>
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