Testing in my lab at CWRU by Gary Doran has indicated that correctly written Numpy code often outperforms the Matlab equivalent. I don't know about R and Julia

Testing in my lab at CWRU by Gary Doran has indicated that correctly written Numpy code often outperforms the Matlab equivalent. I don't know about R and Julia but there isn't usually a speed bottleneck which can be fixed by moving to Matlab from Python.