[Coin-lpsolver] CBC LP Solve Times

[Vishnu Erramilli]

Hi,

Please find attached the output to the screen (log ?) for the problem I
mentioned. I had to kill the run.

Thanks,

Vishnu

> Vishnu,
>
> 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.
>
> 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.
>
> John Forrest
>
>
>
>
>
> "Vishnu Erramilli" <vishnu.erramilli at optessa.com>
> Sent by: coin-lpsolver-bounces at list.coin-or.org
> 01/12/2007 12:24 PM
>
> To
> coin-lpsolver at list.coin-or.org
> cc
>
> Subject
> [Coin-lpsolver] CBC LP Solve Times
>
>
>
>
>
>
> Hi,
>
> I have been working with a problem with the following characteristics (as
> given by the CBC pre-solver): 47333 rows, 139880 columns, 1714427 elements
> and there is an issue related to LP solve times (using the clp solver):
>
> 1) It took 37703.8 seconds to solve the LP problem on CBC. It seems to be
> taking too much time because I ran the same problem on two different
> solvers and one took ~2000 seconds and the other took 30 seconds which
> leads me to conclude that there is definitely some setting issues with my
> current CBC executable.
>
> 2) I am using the cbcExampleSample2 exe to solve the problem.
>
> Is there any reason why an LP could have such a drastic difference in
> solve times? Is there a CBC executable that any on this discussion board
> use that I could use to reduce the solve times?
>
> I think there is definitely some issue if the LP is taking 10 hours to
> solve. I would be thankful if anybody could point me in the right
> direction as regards to settings/exe's of the CBC solver that could
> optimize the solve times.
>
> Thanks,
>
> Vishnu
>
>
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