[Rd] crossprod(): g77 versus gfortran
simon.urbanek at r-project.org
Wed Mar 6 05:46:05 CET 2013
On Mar 5, 2013, at 10:38 PM, Benjamin Tyner wrote:
> Thank you Brian. So it sounds like appendix B.6 of
> 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.
I think you misunderstood - you can use g77 but you will also need F90-capable Fortran - typically gfortran - unless you have other source for LAPACK and that's what B.6 says explicitly.
> 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
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