complex.h in R
Hi, I checked config.log and BLAS_LIBS was not set. However, I have set BLAS_LIBS='-L/usr/lib64 -lblas' in config.site file. I can't figure out why BLAS_LIBS is not set, when PGI compiler is used. When gcc is used, BLAS_LIBS need not be set in config.site and automatically get picked up by the configuration script. Here is a snapshot of the configuration script output (for buidling R with PGI compiler): checking for complex.h... yes checking for double complex... no checking for sgemm_ in -L/usr/lib64 -lblas... yes checking whether double complex BLAS can be used... no Is there other thing I should look into in the config.log? Your help is very much appreicated. Thanks, Jennifer
Prof Brian Ripley wrote:
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.