Book Image

The Reinforcement Learning Workshop

By : Alessandro Palmas, Emanuele Ghelfi, Dr. Alexandra Galina Petre, Mayur Kulkarni, Anand N.S., Quan Nguyen, Aritra Sen, Anthony So, Saikat Basak
Book Image

The Reinforcement Learning Workshop

By: Alessandro Palmas, Emanuele Ghelfi, Dr. Alexandra Galina Petre, Mayur Kulkarni, Anand N.S., Quan Nguyen, Aritra Sen, Anthony So, Saikat Basak

Overview of this book

Various intelligent applications such as video games, inventory management software, warehouse robots, and translation tools use reinforcement learning (RL) to make decisions and perform actions that maximize the probability of the desired outcome. This book will help you to get to grips with the techniques and the algorithms for implementing RL in your machine learning models. Starting with an introduction to RL, youÔÇÖll be guided through different RL environments and frameworks. YouÔÇÖll learn how to implement your own custom environments and use OpenAI baselines to run RL algorithms. Once youÔÇÖve explored classic RL techniques such as Dynamic Programming, Monte Carlo, and TD Learning, youÔÇÖll understand when to apply the different deep learning methods in RL and advance to deep Q-learning. The book will even help you understand the different stages of machine-based problem-solving by using DARQN on a popular video game Breakout. Finally, youÔÇÖll find out when to use a policy-based method to tackle an RL problem. By the end of The Reinforcement Learning Workshop, youÔÇÖll be equipped with the knowledge and skills needed to solve challenging problems using reinforcement learning.
Table of Contents (14 chapters)
Preface
Free Chapter
2
2. Markov Decision Processes and Bellman Equations

The ε-Greedy Algorithm

Another variation of the Greedy algorithm is the ε-Greedy algorithm. For Explore-then-commit, the amount of forced exploration depends on the settable parameter, T, which again gives rise to the question of how to best set it. For ε-Greedy, we do not explicitly require the algorithm to explore more than one round for each arm. Instead, we leave it to chance to determine when the algorithm should carry on exploitation, and when it should explore a seemingly suboptimal arm.

Formally, an ε-Greedy algorithm is parameterized by a number, ε, between zero and one, denoting the exploration probability of the algorithm. After the first exploration rounds, the algorithm will choose to pull the arm with the greatest running reward average with probability 1 - ε. Otherwise, it will uniformly choose one out of all the available arms (with probability ε). Unlike Explore-then-commit, where we know for sure the algorithm will be forced...