If you've marvelled at the Fast Inverse Square Root method and want to use this piece of witchcraft to speed up your Python code, stop! Just stick with writing x ** -0.5. It will be much faster than ...

(1) I tried to optimize the existing R function "sqrtm" in R package "expm" with Rcpp. (2) Introduced how to compute the square root of matrix with the existing function in Python. (3) Implemented ...