[Rd] complex.h in R

[Prof Brian Ripley]

On Sat, 24 Sep 2005, Jennifer Lai wrote:

> Hi,
>     How does complex.h used in R? Whether a compiler support complex.h
> or not, does it affect R's performance?

complex.h will only used in future (2.2.0-to-be) versions of R, and only
if configure finds enough C99 support. Otherwise R's own C-level complex
support is used, as it always was.  One would expect the OS's support to
be faster and more accurate (but one could be disappointed, we have
found).

> I used PGI compiler to build
> R-devel on AMD Opteron, but the configuration file failed to link BLAS
> library despite the fact it is located in the usual location,
> /usr/lib64.

Look in config.log to find out why.

> PGI said they don't support complex.h. R configuration
> script printed out that doublecomplex is not supported.

That is *FORTRAN* DOUBLE COMPLEX, and that does affect the operation of R,
as without it you will not have complex linear algebra support.

> Are "supporting
> complex.h" and "linking BLAS library" related?

No.  They are completely orthoogonal concepts.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595