Jean Zay: The BLAS library

BLAS (Basic Linear Algebra Subprograms) is a set of functions effectuating basic linear algebra operations such as vector addition, scalar products and matrix multiplication. BLAS is available via the Math Kernel Library (MKL) (recommended version) or in free versions (via LAPACK or OpenBLAS).

• Intel MKL with Intel compilers (recommended version)
• Via LAPACK 3.8.0 with the GCC 8.2.0 compiler
• Via LAPACK 3.8.0 with the 9.1.0 compiler
• Via LAPACK 3.8.0 with the Intel 2019.4 compiler
• OpenBLAS 0.3.6 with the GCC 8.2.0 compiler
• OpenBLAS 0.3.6 with the GCC 9.1.0 compiler
• OpenBLAS 0.3.6 with the Intel 2019.4 compiler

MKL contains optimised implementations of the BLAS library. The library is directly accessible via the Intel compiler by using the module command:

$ module load intel-compilers/19.0.4 intel-mkl/19.0.4

To know which versions are installed on the machine:

$ module avail intel-compilers
$ module avail intel-mkl

For the linking, you must add the following options:

 '-L${MKLROOT}/lib/intel64 -lmkl_intel_lp64 -lmkl_sequential -lmkl_core -lpthread -lm -ldl'

The options can vary from one version to another depending on the compiler used. Linking information can also be found on Intel MKL Link Line Advisor.

The library is accessible by loading LAPACK with the following command:

$ module load netlib-lapack

To know which versions are installed on the machine:

$ module avail netlib-lapack

Important: At the linking, you must add the -lblas option.

The library is accessible with the following command:

$ module load openblas

To know which versions are installed on the machine:

$ module avail openblas

Important: At the linking, you must add the -lopenblas option.

Reference site (Netlib)

Reference site (OpenBLAS)

Intel MKL Get Started site

Intel MKL Link Line Advisor