<br><font size=2 face="sans-serif">Vishnu,</font>
<br>
<br><font size=2 face="sans-serif">I agree that it sounds a long time to
solve an LP. It sounds as if you are referring to the initial solve
of the LP relaxation of an IP and maybe some settings are not as good as
they could be for an LP.</font>
<br>
<br><font size=2 face="sans-serif">You could try using the stand-alone
executable "clp" and just do clp filename and see if that is
better. Or you can send me a logfile or the mps file to look at.</font>
<br>
<br><font size=2 face="sans-serif">John Forrest</font>
<br>
<br>
<br>
<br>
<br>
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<td width=40%><font size=1 face="sans-serif"><b>"Vishnu Erramilli"
<vishnu.erramilli@optessa.com></b> </font>
<br><font size=1 face="sans-serif">Sent by: coin-lpsolver-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">01/12/2007 12:24 PM</font>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">coin-lpsolver@list.coin-or.org</font>
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<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td>
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<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">[Coin-lpsolver] CBC LP Solve Times</font></table>
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<br>
<br><tt><font size=2>Hi,<br>
<br>
I have been working with a problem with the following characteristics (as<br>
given by the CBC pre-solver): 47333 rows, 139880 columns, 1714427 elements<br>
and there is an issue related to LP solve times (using the clp solver):<br>
<br>
1) It took 37703.8 seconds to solve the LP problem on CBC. It seems to
be<br>
taking too much time because I ran the same problem on two different<br>
solvers and one took ~2000 seconds and the other took 30 seconds which<br>
leads me to conclude that there is definitely some setting issues with
my<br>
current CBC executable.<br>
<br>
2) I am using the cbcExampleSample2 exe to solve the problem.<br>
<br>
Is there any reason why an LP could have such a drastic difference in<br>
solve times? Is there a CBC executable that any on this discussion board<br>
use that I could use to reduce the solve times?<br>
<br>
I think there is definitely some issue if the LP is taking 10 hours to<br>
solve. I would be thankful if anybody could point me in the right<br>
direction as regards to settings/exe's of the CBC solver that could<br>
optimize the solve times.<br>
<br>
Thanks,<br>
<br>
Vishnu<br>
<br>
<br>
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<br>