Re: [ublas] Cholesky factorization

From: n.torrey.pines_at_[hidden]
Date: 2007-03-19 13:52:09

On 3/19/07, Benjamin Sobotta <mayday_at_[hidden]> wrote:

> From a performance point of view it is adviseable to use the
> boost::bindings library to link against some optimized version of LAPACK,
> i.e. ATLAS.

I wonder, should one expect significant performance differences
between these three versions, while implementing something like
Cholesky factorization:

1. F77/LAPACK using ATLAS for BLAS procedures (essentially no uBlas)
2. uBlas using ATLAS (only for BLAS procedures)
3. pure uBlas

for

a. small (N < 10)
b. medium (N = 10-100)
c. large (N > 1000)

matrix sizes?

I remember seeing some message in the archives, saying uBlas is very
slow (incidentally, the performance benchmark may have been Cholesky
factorization), but I wasn't sure if the poster remembered to turn the
debugging off and the optimizations on.