[cbarrick]

MKL is usually what you want if you are doing matrix math on an Intel CPU.

A better design is to make it easy you to choose or hotswap your BLAS/LAPACK implementation. E.g. OpenBLAS for AMD.

Edit: To be clear, Netlib (the reference implementation) is almost always NOT what you want. It's designed to be readable, not optimized for modern CPUs.

[jacobgorm]

I would argue that BLIS is what you want. It is proper open source and not tied to Intel platforms.