This repository is largely uneeded now. Homebrew formula R now uses OpenBLAS (see the formula, while homebrew cask R (the CRAN release) provides a means to change from reference BLAS to Accelerate, see: macOS FAQ.
R Homebrew Formula that lets you select which BLAS library is used (Reference/Apple Accelerate/OpenBLAS)
Based on the homebrew-core r.rb:
https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/r.rb
This formula supports options regarding BLAS library.
If you use no flags, then you get the R reference BLAS.
But, you can also do:
--with-accelerate
This will use Apple's Accelerate BLAS.
--with-openblas
This will use OpenBLAS, see http://openblas.net
If you also use:
--with-lapack
then any LAPACK library included in your BLAS library will also be used——this may be a bad idea?
For more information check:
https://cran.r-project.org/doc/manuals/r-patched/R-admin.html#Linear-algebra