$ brew install openblas
This formula is keg-only, which means it was not symlinked into /usr/local,
because macOS provides BLAS and LAPACK in the Accelerate framework.
For compilers to find this software you may need to set:
For pkg-config to find this software you may need to set:
$ gem install numo-linalg -- --with-openblas-dir=/usr/local/opt/openblas