October 7, 2019

The best way to sample from an iteratively built matrix in Python

While coding up a reinforcement learning algorithm in python, I came across a problem I had never considered before… What’s the fastest way to sample from an array while iteratively building it? If you’re reading this, you should first question whether you actually need to iteratively build and sample from a python array in the first place. If you can build the array first and then sample a vector from it using np. Read more

September 10, 2019

When is Python's built-in random module faster than NumPy?

TL;DR If you need a single random number (or up to 5) use the built-in random module instead of np.random. An instinct to vectorize An early learning for any aspiring pandas user is to always prefer “vectorized” operations over iteratively looping over individual values in some dataframe. These operations—which include most built-in methods—are compiled into Cython and executed at blazing-fast speeds behind the scenes. It is very often worth the effort of massaging your logic into a slightly less expressive form if you can leverage vectorized functions to avoid the performance hit of for-loops. Read more

© Geoff Ruddock 2019