https://github.com/andreaferretti/nimblas
as well as LAPACK:
https://github.com/andreaferretti/nimlapack
For an example, consider calling the least squares routine `dgelsd` in arraymancer:
https://github.com/mratsim/Arraymancer/blob/master/src/array...
wrapped up in a nicer user facing API.
Feel free to hop onto matrix, if you have more questions!