I'm the kind of person who finds himself reading about a new technology or a cool algorithm, and tries to implement it based on the high-level description. Unfortunately, I don't always guess everything correctly, and sometimes the implementation turns out to not work; or it kind of works, but not as well as expected, which can be even worse.

A key example of this for me was when I read about Evolutionary Algorithms. At the core, it's sounds so ingeniously simple:

Create a population of individuals
Score the individuals based on some performance metric
Kill off the weakest performers
Create children from the surviving parents
If not finished, go to #2

PDF file of book (5th printing with corrections, Feb 2011)

Typically, these decisions are made by a product person and are passed off to researchers and engineers to implement. The problem with this approach is that ML-core products are intimately constrained by what is technically and algorithmically feasible. In my experience, having a technical understanding of the range of related ML problems can inspire product ideas that might not occur to someone without this understanding. To draw a loose analogy, it's like architecture. So much of the construction of a bridge is constrained by material resources and physics that it doesn't make sense to have people without that technical background design a bridge.

The goal of all this is to say that if you want to build a rich ML product, you need to have a rich product/design/research/engineering team.

The Naive Bayes classifier is one of the most versatile machine learning algorithms that I have seen around during my meager experience as a graduate student, and I wanted to do a toy implementation for fun. At its core, the implementation is reduced to a form of counting, and the entire Python module, including a test harness took only 50 lines of code. I haven’t really evaluated the performance, so I welcome any comments. I am a Python amateur, and am sure that experienced Python hackers can trim a few rough edges off this code.