[Clp] Do I need Lapack/BLAS

[Haroldo Santos]

Thanks Forrest.

I'll run some tests with versions compiled with and without Lapack.

On Wed, Dec 1, 2010 at 7:29 AM, John Forrest <john.forrest at fastercoin.com>wrote:

> Haroldo,
>
> Not a perfect answer ....
>
> If Lapack is built in then you can see if it is activated on a
> particular problem by setting the log level high enough.  So -
>
> clp nug12.mps -log 3 -duals  (nug12 from miplib)
> gives output such as -
>
> 0  Obj 0 Primal inf 24 (24)
>        length of U 2383, length of L 202
> 138  Obj 8.1224 Primal inf 593.6 (385)
>        length of U 2653, length of L 357
> 276  Obj 24.1951 Primal inf 682.15 (485)
>        length of U 2931, length of L 545
> 414  Obj 40.1535 Primal inf 637.5 (496)
>        length of U 3352, length of L 706
> and later
> 88658  Obj 522.894 Dual inf 1.07841 (275)
>    length of U 17298, length of L 15214 plus 80089 from 283 dense rows
> 88666  Obj 522.894 Dual inf 2.27984 (293)
>    length of U 17538, length of L 15454 plus 80656 from 284 dense rows
> 88683  Obj 522.894 Dual inf 5.77515 (324)
>    length of U 18382, length of L 16063 plus 79524 from 282 dense rows
> 88700  Obj 522.894
>
> which enables you to see that Lapack is being used on dense section.
>
> You can also see that it is not used on dfl001.mps from netlib, but is
> used on pilot87.
>
> John Forrest
>
>
>
> On Tue, 2010-11-30 at 23:00 -0200, Haroldo Santos wrote:
> > Dear All,
> >
> > Some time ago I asked what differences could have a CLP build
> > including Lapack from another without.
> > I was informed that Lapack would allow a better performance in the
> > case of having some dense matrix.
> >
> > Since Lapack increases the build size/dependencies, I would like to
> > know if there is an easy way to determine if it is being activated for
> > a given linear program (e.g., by looking at the terminal output).
> >
> > Anyone has benchmarks indicating how much does it helps ?
> > In common benchmarks, for instance:
> > http://plato.asu.edu/ftp/milpf.html
> > It is activated ? Would it help in these problems ?
> >
> > Thanks,
> >
> > Haroldo
> >
> > --
> > =============================================================
> > Haroldo Gambini Santos
> > Computing Department - Universidade Federal de Ouro Preto - UFOP
> > email: haroldo [at ] iceb.ufop.br
> > home/research page: http://www.iceb.ufop.br/decom/prof/haroldo/
> >
> > "Computer science is no more about computers than astronomy
> > is about telescopes." Edsger Dijkstra
> >
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>
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-- 
=============================================================
Haroldo Gambini Santos
Computing Department - Universidade Federal de Ouro Preto - UFOP
email: haroldo [at ] iceb.ufop.br
home/research page: http://www.iceb.ufop.br/decom/prof/haroldo/

"Computer science is no more about computers than astronomy
is about telescopes." Edsger Dijkstra
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