"If you specifically want numpy, it may be possible to have Common Lisp talking to python." CL can run python (uiop:run-program "python3 ~/quicklisp/local-projects/clvpy/hello.py" :output t) This isn't 1950 anymore. 1950s biases about what "efficiency" means no longer apply. (Lisp used to be concerned with "development time efficiency" and can be again) pt