[Rd] crossprod(): g77 versus gfortran

[Benjamin Tyner]

Thank you Brian. So it sounds like appendix B.6 of

   http://cran.r-project.org/doc/manuals/R-admin.html

should be updated to reflect that g77 is no longer supported; I will
notify CRAN at R-project.org of this unless you suggest a different recipient.

In any case, I tried again but using gfortran version 4.4.0, and now the
timings are back to what they were under g77.

As for BLAS, was using the one that ships with R, as wanted to keep
things simple for benchmarking purposes.

Thanks again.

> On 05/03/2013 01:45, Benjamin Tyner wrote:
> >/ Hi
> />/
> />/ I've got two builds of R, one using g77 (version 3.4.6) and the other
> />/ using gfortran (version 4.1.2). The two builds are otherwise identical
> />/ as far as I can tell. The one which used g77 performs crossprod()s
> />/ roughly twice as fast as the gfortran one. I'm wondering if this rings a
> />/ bell with anyone, and if so, are you aware of any configure settings
> />/ which will improve the performance when using gfortran. This is on RHEL 5.
> /
> Note that recent versions of R do not build with g77, and have 
> performance improvements in linear algebra.  So please follow the 
> posting guide and give up the 'at a minimum' information requested and a 
> reproducible example.
>
> Also, check what BLAS is in use: an optimized BLAS can make a lot of 
> difference on such simple operations.
>
>
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk <https://stat.ethz.ch/mailman/listinfo/r-devel>
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/ <http://www.stats.ox.ac.uk/%7Eripley/>
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595