The marvelous bee odometer

You probably know that not only can bees compute the vector (direction and distance) to a discovered food source relative to their hive, but they can also convey this vector to their hive mates. Here, I'll talk a little bit about one component of this system - the Bee odometer: how do bees figure out …

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Derived classes and std::vector

I want to talk about a fun corner of C++ I ran into recently. It has to do with how to handle calling member functions of a list of heterogenous objects. My use case was a bit like the following: say we have a bunch of different functions - a * x^2, b * x, …

Chromecast audio: command line

When I was casting about (I'm allowed one Dad pun per article. Oops, I mean bad pun. Sorry that was two much fun.)  for home audio solutions (It's what the kids call speakers these days) a friend of mine encouraged me to try out Google's Chromecast Audio device. And so another internet connected creature entered our …

functools.partial

functools.partial is one of those things that you don't need until you need it, and then you need it badly. Trying to create a series of lambda functions I discovered that the simplest answer that came to my mind did something counter intuitive, and functools.partial - which I had ignored so far, came to my rescue. …

Self-Organizing Maps

Self-organizing maps are an old idea (first published in 1989) and take strong inspiration from some empirical neurophysiological observations from that time. The original paper "Self-Organizing Semantic Maps" by Ritter and Kohonen (pdf) has a nice discussion that took me back to some questions I was looking at in another life as a neurophysiologist. The …

Bayesian networks and conditional independence

Bayesian networks are directed graphs that represent probabilistic relationships between variables. I'm using the super-excellent book "Pattern Recognition and Machine Learning" by C. Bishop as my reference to learn about bayesian networks and conditional independence, and I'd like to share some intuitions about these. First, let's motivate our study with a common home situation related …

CIGAR strings

When I first joined Seven Bridges my boss would be describing things and he would say "Do this with the CIGAR" or "compute that from the CIGAR". Reluctant to be found out so early I nodded sagely and made a furtive note in my notebook to check out what the heck a CIGAR was. You …