BLAS is a set of functions for basic linear algebra operations. Vendors often supply BLAS libraries optimized for their hardware. A large portion of the computational engine in COMSOL Multiphysics relies on BLAS. Included with COMSOL Multiphysics is the MKL (Math Kernel Library) BLAS library, which is the default BLAS library. For AMD processors, COMSOL Multiphysics also includes the ACML (AMD Core Math Library) BLAS library, optimized for AMD processors with SSE2 support, which might improve performance in some cases. It is also possible to supply another BLAS library optimized for your hardware. See the COMSOL Multiphysics Installation Guide for information about how to override the default BLAS library (MKL). If the library you want to use is unavailable or incorrectly installed, COMSOL Multiphysics switches to the default BLAS library.