<p dir="ltr">Hi Bitar,</p>
<p dir="ltr">Clp itself is single threaded (only cbc can run in parallel while processing the search tree, the root node is sequential anyway).</p>
<p dir="ltr">There is an alternative lp solver in coin which can run in parallel: aboca, you could try this. </p>
<p dir="ltr">Cheers</p>
<div class="gmail_quote">Em 04/12/2013 09:24, "Bitar Fadi" <<a href="mailto:Fadi.Bitar@sweco.se">Fadi.Bitar@sweco.se</a>> escreveu:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal">Hi,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">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.
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">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).<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">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).<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">What am I missing here ? Has anybody had a successful experience in getting such a scenario running in parallel on a windows machine ?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Thanks a lot for the help.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">/ Fadi <u></u><u></u></p>
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