To improve the simulation speed of MATLAB Function block algorithms that call certain low-level vector and matrix functions (such as matrix multiplication), Simulink® can call BLAS functions. BLAS is a software library for low-level vector and matrix computations that has several highly optimized machine-specific implementations. If the input arrays for the matrix functions meet certain criteria, the simulation calls BLAS functions in the BLAS library that is included with MATLAB®.
If you use Simulink Coder™ to generate code for these algorithms, you can specify that the code generator produce BLAS function calls. The code generator uses the CBLAS C interface to BLAS. If you specify that you want to generate BLAS calls, and the input arrays for the matrix functions meet the criteria, the code generator produces BLAS calls. The build process links to the BLAS library that you specify. See Speed Up Matrix Operations in Code Generated from a MATLAB Function Block (Simulink Coder).