[Coin-discuss] Clustering COIN?

[anthony at resolution.com]

Ted and Yan,

Thanks very much!  Check your email, I sent you each the MPS file (if you
work together and that was double work, I apologize).  I'm sorry for its
size, however, our class of problems (scheduling) quickly gets out of
hand.  Unfortunately, we're not really O/R experts .... we wrote some of
the basic model, had it tweaked by an expert, and now have to decide if we
want to move to a commercial solver or to a parallel solver to get the
speed we need.  If possible, I'd rather not shackle myself to a commercial
solver :-)

In fact, I'd rather pay (and contribute) for someone to improve an OS
project, but now I'm getting off-topic.

Thanks again!

--
Anthony

> anthony at resolution.com wrote:
>
>> I hope this finds you well.  Great information about the parallel
>> solver.
>>
>> I've downloaded COPS and am looking into installing and setting it up.
>> It
>> looks like it relies on MPI to handle the messaging?  We'd be happy to
>> share our experience w/ building a cluster out with COPS if it works for
>> us!
>
> Yes, it uses MPI.
>
>> A few questions before we go too far in the right / wrong direction:
>>
>> 1.  We're using CBC right now to solve an MPS file.  Does COPS read MPS
>> files?
>
> Yes, BLIS will read MPS files.
>
>> 2.  Our model runs around 3 hours at the moment, with CBC.  Do you have
>> any idea what type of performance we could see with COPS?
>
> It's difficult to say. We haven't done any direct comparisons between
> the two and it would depend on problem structure, etc. Generally
> speaking, CBC should outperform BLIS on a single processor, but for any
> given instance or class of models, of course, anything goes. There are
> lots of hooks for customizing BLIS (similar to those in CBC), so it
> might be possible to improve the performance by customizing if you are
> solving the same classes of models repeatedly....
>
>> 3.  I've got an MPS file .... any chance I could get you to run it on
>> your
>> cluster and see what type of performance we're looking at .... before we
>> spend several days rolling out a solution which might not work?
>
> Sure, I could give it a try. We just got a new cluster here that we are
> playing with, so I can see what happens.
>
>> Again, if this is a valid solution for us, we'll probably use EC2 as our
>> architecture, and I'd be happy to share the results.
>
> It would be great to see it running on something like EC2, so we're
> happy to give you whatever help you need.
>
> Cheers,
>
> Ted
> --
> Dr. Ted Ralphs
> Associate Professor
> Industrial and Systems Engineering
> Lehigh University
> (610)758-4784
> ted at lehigh dot edu
> www.lehigh.edu/~tkr2
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