Machine learning is becoming a mainstream technology any journeyman software engineer can apply. We expect engineers to know how to take an average and standard deviation of data. Perhaps it’s now reasonable to expect a non-expert to be able to train a learning model to predict data, or apply PCA or k-means clustering to better understand data.

The key change that’s enabling high end machine learning like Siri or self driving cars is the availability of very large computing clusters. Machine learning works better the more data you have, so being able to easily harness 10,000 CPUs to process a petabyte of data really makes a difference. For us civilians with fewer resources, libraries like scikit-learn and cloud services make it possible for us to, say, train up a neural network without knowing much about the details of backpropagation.

The danger of inexpert machine learning is misapplication. The algorithms are complex to tune and apply well. A particular worry is overfitting, where it looks like your system is predicting the data well but has really learned the training data too precisely and it won’t generalize well. Being able to measure and improve machine learning systems is an art that I suspect can only be learned with lots of practice.

I just finished an online machine learning course that was my first formal introduction. It was pretty good and worth my time, you can see my detailed blog posts if you want to know a lot more about the class. Now I’m working on applying what I’ve learned to real data, mostly using IPython and scikit-learn. It’s challenging to get good results, but it’s also fun and productive.