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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Index

Training: cross-entropy

To train the first approximation of the model, the cross-entropy method is used and implemented in train_crossent.py. During the training, we randomly switch between the teacher-forcing mode (when we give the target sequence on the decoder's input) and argmax chain decoding (when we decode the sequence one step at a time, choosing the token with the highest probability in the output distribution). The decision between those two training modes is taken randomly with the fixed probability of 50%. This allows for combining the characteristics of both methods: fast convergence from teacher forcing and stable decoding from curriculum learning.

Implementation

What follows is the implementation of the cross-entropy method training from train_crossent.py.

SAVES_DIR = "saves"
BATCH_SIZE = 32
LEARNING_RATE = 1e-3
MAX_EPOCHES = 100
log = logging.getLogger("train")
TEACHER_PROB = 0.5

In the beginning, we define hyperparameters...