[R] Question about building library and BLAS

[Zhu Wang]

On Mon, 2004-05-31 at 11:39, Douglas Bates wrote:

> I should have read your message more carefully.  Those three Fortran
> routines that you mention are single precision and it would be silly
> to use them on modern computers.  R only provides single precision
> floating point for compatibility.  All numerical linear algebra is
> doing in double precision.  Check where sgefa and sgesl are being
> called and see if they really need to be in single precision.  I'm
> sure if you replace them by calls to dgefa and dgesl (and suitably
> change the precision of the arguments) they will run as fast as
> before. 

Thanks. I have replaced sgefa and sgesl with dgefa and dgesl. The
results are confirmed by running the compiled Fortran code. I will
convey this to the original author.

>  In fact you can probably use the Lapack routines dgetrf and
> dgetrs instead and get a performance boost.

I will try to improve later.

-- 
Zhu Wang