The CBLAS library provides C wrappers for Fortran BLAS functions, which, on Blue Waters, come from the ACML library.  Because the ACML module conflicts with the Cray compiler (cce), CBLAS is currently only available under the GNU and PGI programming environments.  One must first switch to one of those environments before attempting to load the CBLAS module.  Otherwise, the load will fail.

How to use CBLAS

First, one must switch to GNU or PGI.  For example, from the Cray programming environment:

% module swap PrgEnv-cray PrgEnv-gnu

Then load the cblas module, which will automatically load the acml module, as well:

% module load cblas

To view a list of available cblas modules:

% module avail cblas

To view more information on the cblas module:

% module show cblas

For a couple simple examples, download the CBLAS source (see link below), extract it, and look in the examples directory.

Additional Information