Message-ID: <CAL6gwn+S_8pgB9fvVpds6mFzSWWB+t+Swz4-5QsbwPi_t_S6fA@mail.gmail.com>
Date: 2014-04-27T20:06:08Z
From: Avraham Adler
Subject: [Rcpp-devel] Significant difference in performance when computing Ax
In-Reply-To: <21341.21517.420012.964359@max.nulle.part>
I understand and agree that it is a feature; I just should have
realized that crossprod using a fast BLAS is an unfair comparison to
non-BLAS using routines. Then again, it's another reason to use fast
BLAS's. I wish that R for windows would allow the use of an optimized
LAPACK too. Oh well.
Thanks,
Avi
On Sun, Apr 27, 2014 at 3:01 PM, Dirk Eddelbuettel <edd at debian.org> wrote:
>
> On 27 April 2014 at 14:34, Avraham Adler wrote:
> | I feel foolish now. I forgot to note that I build R using a Win64
> | version of OpenBLAS (see
> | <http://www.avrahamadler.com/2014/04/20/r-3-1-0-openblas-speed-comparisons/>
> | for more). I'm certain that the speed in tcrossprod is coming from an
> | optimized compile of R and BLAS. My apologies for any confusion.
>
> That is a _feature_ and not a bug. See eg this r-devel tread from 2005:
>
> http://thread.gmane.org/gmane.comp.lang.r.devel/2370/
>
> Oh the good old days when Doug Bates still posted on r-devel ...
>
> Dirk
>
> --
> Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com