Once I upgraded to a Codecademy Pro membership, I started taking courses from its Python catalog with the goal of building a foundation to understand deep learning neural networks. Aside from a few scenic detours, most of my course choices were intended to build upon each other to fulfill what I consider prerequisites for a Codecademy “Skill Path”: Build Deep Learning Models with TensorFlow
This was the first “Skill Path” I took, and I wasn’t quite sure what to expect as Codecademy implied they are different than the courses I took before. But once I got into this “skill path”… it feels pretty much like another course. Just a longer one, with more sessions. It picked up where the “Learn the Basics of Machine Learning” course left off with neural perceptrons, and dived deeper into neural networks.
In contrast to earlier courses that taught various concepts by using them to solve regression problems, this course spent more time on classification problems. We are still using
scikit-learn a lot, but as promised by the title we’re also using TensorFlow. Note the course work mostly stayed in the Keras subset of TensorFlow 2 API. Keras used to be a separate library for making it easier to work with TensorFlow version 1, but it has since been merged into TensorFlow version 2 as part of the big revamp between versions.
I want to call attention to an item linked as “additional resources” for the skill path: a book titled “Deep Learning with Python” by François Chollet. (Author, or at least one of the primary people, behind Keras.) Following various links associated with the title, I found that there’s since been a second edition and the first chapter of the book is available to read online for free! I loved reading this chapter, which managed to condense a lot of background on deep learning into a concise history of the field. If the rest of the book is as good as the first chapter, I will learn a lot. The only reason I haven’t bought the book (yet) is that, based on the index, the book doesn’t get into unsupervised reinforcement learning like the type I want to put into my robot projects.
Back to the Codecademy course…. err, skill path: we get a lot of hands-on exercises using Keras to build TensorFlow models and train them on data for various types of problems. This is great, but I felt there was a significant gap in the material. I appreciated learning that different loss functions and optimizers will be used for regression versus classification problems, and we put them to work in their respective domains. But we were merely told which function to use for each exercise, the course doesn’t go into why they were chosen for the problem. I had hoped that the Keras documentation Optimizers Overview page would describe relative strengths and weaknesses of each optimizer, but it was merely a list of optimizers by name. I feel like such a comparison chart must exist somewhere, but it’s not here.
I didn’t quite finish this skill path. I lost motivation to finish the “Portfolio Project” portion of the skill path where we are directed to create a forest cover classification model. My motivation for deep learning lies in reinforcement learning, not classification or regression problems, so my attention has wandered elsewhere. At this point I believe I’ve exhausted all the immediately applicable resources on Codecademy as there are no further deep learning material nor is there anything on reinforcement learning. So I bid a grateful farewell to Codecademy for teaching me many important basics over the past few months and started looking elsewhere.