[Cbc] How much better CBC performs when compiled with BLAS and LAPACK ?

[John Forrest]

To add to Haroldo's comments.

a) I think that the configure script can detect the existence of lapack 
and blas - well it does on my computer.

b) A dense factorization only really starts to help when the dense part 
is of the order of 500.  Most "solvable" integer problems tend not to 
fall in that category.

c) However many difficult LP's do, with the dense part being of the 
order of several thousand.  As the factorization effort is proportional 
to n**3, a good set of blas makes a big difference. For the latest set 
of simplex benchmarks by Hans Mittelmann, I asked him to include the 
library "openblas", which made a significant difference.

John Forrest

On 31/01/15 04:03, Haroldo Gambini Santos wrote:
> Hi all,
>
> Some years ago I asked this question.
>
> LAPACK and BLAS are fortran codes which can be compiled as Third-part 
> components of CBC and may help in dense factorization operations.
>
> As part of my CBC benchmarking project I compared the CBC builds with 
> and without these components.   Apparently there is a very small gain 
> when this code is included:
>
> http://cbc.decom.ufop.br
>
> Cheers,
>
> Haroldo
>