Book Image

Deep Reinforcement Learning Hands-On - Second Edition

By : Maxim Lapan
5 (2)
Book Image

Deep Reinforcement Learning Hands-On - Second Edition

5 (2)
By: Maxim Lapan

Overview of this book

Deep Reinforcement Learning Hands-On, Second Edition is an updated and expanded version of the bestselling guide to the very latest reinforcement learning (RL) tools and techniques. It provides you with an introduction to the fundamentals of RL, along with the hands-on ability to code intelligent learning agents to perform a range of practical tasks. With six new chapters devoted to a variety of up-to-the-minute developments in RL, including discrete optimization (solving the Rubik's Cube), multi-agent methods, Microsoft's TextWorld environment, advanced exploration techniques, and more, you will come away from this book with a deep understanding of the latest innovations in this emerging field. In addition, you will gain actionable insights into such topic areas as deep Q-networks, policy gradient methods, continuous control problems, and highly scalable, non-gradient methods. You will also discover how to build a real hardware robot trained with RL for less than $100 and solve the Pong environment in just 30 minutes of training using step-by-step code optimization. In short, Deep Reinforcement Learning Hands-On, Second Edition, is your companion to navigating the exciting complexities of RL as it helps you attain experience and knowledge through real-world examples.
Table of Contents (28 chapters)
26
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27
Index

The experiment results

Unfortunately, the paper provided no details about very important aspects of the method, like training hyperparameters, how deeply cubes were scrambled during the training, and the obtained convergence. To fill in the missing blanks, I did lots of experiments with various values of hyperparameters, but still my results are very different from those published in the paper. First of all, the training convergence of the original method is very unstable. Even with a small learning rate and a large batch size, the training eventually diverges, with the value loss component growing exponentially. Examples of this behavior are shown on the figure that follows.

Figure 24.5: The policy loss (left) and value loss (right) of two runs of the paper's method

After several experiments with this, I came to the conclusion that this behavior is a result of the wrong value objective being proposed in the method. Indeed, in the formula , the value returned by the...