[CHiPPS] Fwd: Questions on Blis

[Ted Ralphs]

We have been testing BLIS with some fairly large instances recently,
and have also been running into memory problems on long runs with
small numbers of processors. How many rows do your instances have? How
many nonzeros? What is the platform you are running it on? We are also
looking at ways to reduce the memory footprint. Of course,
distributing the computation over more processors works to some
degree. I never really thought about the idea of using standard
compression software to compress the node description. I would be
surprised if it had much effect in most cases, since the data are
already compressed by the use of sparse vectors and matrices
everywhere and also by storing subtrees by differencing, etc. I guess
it should be easy to try, though. Are you using BLIS out of the box to
solve instances in MPS format or do you have application-specific
methods that you are using with BLIS?

Cheers,

Ted

On Fri, Mar 13, 2009 at 3:12 AM, Alessandro Tiberi
<alessandro.tiberi at gmail.com> wrote:
> Yan Xu ha scritto:
>> As to gap, you are right. The best bound seems do not move. The parallel log was changed to style of commercial solvers last year, I did not test much. I will take a look.
>>
> Great, thanks!
>> For a child node, Blis only store the difference with its parent. I haven't thought about zipping and don't know how to do this yet. Any suggestion?
>>
>
> Well, my very preliminary idea is just to apply a simple serialization
> mechanism, so the steps would be:
> 1) Represent a node description as a memory stream
> 2) fed this stream to a zipper
> 3) The Node Desc. wrapper would hence contain the result of 2 plus the
> ability to uncompress it back to Node Des.
>
> But as I said it is very preliminary, and I still do not have a global
> picture...
>
> best,
> Alessandro
>
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--
Dr. Ted Ralphs
Associate Professor, Lehigh University (permanent)
Visiting Professor, Monash University (current)
(610) 628-1280
ted 'at' lehigh 'dot' edu
coral.ie.lehigh.edu/~ted

Sent from: Melbourne Vic Australia.



-- 
Dr. Ted Ralphs
Associate Professor, Lehigh University (permanent)
Visiting Professor, Monash University (current)
(610) 628-1280
ted 'at' lehigh 'dot' edu
coral.ie.lehigh.edu/~ted

Sent from: Melbourne Vic Australia.