[Cbc] Running Cbc/Clp in parallel

[Haroldo Santos]

Hi Bitar,

Clp itself is single threaded (only cbc can run in parallel while
processing the search tree,  the root node is sequential anyway).

There is an alternative lp solver in coin which can run in parallel: aboca,
you could try this.

Cheers
Em 04/12/2013 09:24, "Bitar Fadi" <Fadi.Bitar at sweco.se> escreveu:

>  Hi,
>
>
>
> I’m using Clp as a library in a C++ program to solve very large problems
> (number of variables ~ 42M ). While in the past I have decomposed the
> problem into smaller problems that get solved separately in parallel, I
> have lately been wondering if there was a way to configure clp to make use
> of multi-threading so that I can solve the entire problem in one go, which
> would potentially lead to a better solution since I’m making some
> assumptions while decomposing that I would very much rather not make.
>
>
>
> The reason I went with the decomposition in the first place is that the
> problem, when divided into 52 smaller problems, takes about an hour to
> solve on an Intel i7-powered laptop, and takes forever to solve as a single
> problem on a single thread (in fact, I’ve never waited long enough for it
> to finish).
>
>
>
> The Cbc documentation says that Cbc can be built to run in parallel, and
> I’ve found a few mentions of the CBC_THREAD flag in the Clp code, so I
> figured I could build a Cbc model instead of a Clp model and solve that
> with the added benefit of concurrency, however when I built Cbc with the
> –enable-cbc-parallel and ran it on both Windows 7 and Mac OS X, it didn’t
> seem to make use of multi-threading, since the CPU usage was capped at 25%
> (while with my decomposition method it would go up to 100% throughout the
> optimization, as it would run four solves at a time).
>
>
>
> What am I missing here ? Has anybody had a successful experience in
> getting such a scenario running in parallel on a windows machine ?
>
>
>
> Thanks a lot for the help.
>
>
>
> / Fadi
>
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