Book Image

Deep Learning with TensorFlow and Keras – 3rd edition - Third Edition

By : Amita Kapoor, Antonio Gulli, Sujit Pal
5 (2)
Book Image

Deep Learning with TensorFlow and Keras – 3rd edition - Third Edition

5 (2)
By: Amita Kapoor, Antonio Gulli, Sujit Pal

Overview of this book

Deep Learning with TensorFlow and Keras teaches you neural networks and deep learning techniques using TensorFlow (TF) and Keras. You'll learn how to write deep learning applications in the most powerful, popular, and scalable machine learning stack available. TensorFlow 2.x focuses on simplicity and ease of use, with updates like eager execution, intuitive higher-level APIs based on Keras, and flexible model building on any platform. This book uses the latest TF 2.0 features and libraries to present an overview of supervised and unsupervised machine learning models and provides a comprehensive analysis of deep learning and reinforcement learning models using practical examples for the cloud, mobile, and large production environments. This book also shows you how to create neural networks with TensorFlow, runs through popular algorithms (regression, convolutional neural networks (CNNs), transformers, generative adversarial networks (GANs), recurrent neural networks (RNNs), natural language processing (NLP), and graph neural networks (GNNs)), covers working example apps, and then dives into TF in production, TF mobile, and TensorFlow with AutoML.
Table of Contents (23 chapters)
21
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22
Index

Deep deterministic policy gradient

The DQN and its variants have been very successful in solving problems where the state space is continuous and action space is discrete. For example, in Atari games, the input space consists of raw pixels, but actions are discrete—[up, down, left, right, no-op]. How do we solve a problem with continuous action space? For instance, say an RL agent driving a car needs to turn its wheels: this action has a continuous action space.

One way to handle this situation is by discretizing the action space and continuing with a DQN or its variants. However, a better solution would be to use a policy gradient algorithm. In policy gradient methods, the policy is approximated directly.

A neural network is used to approximate the policy; in the simplest form, the neural network learns a policy for selecting actions that maximize the rewards by adjusting its weights using the steepest gradient ascent, hence the name: policy gradients.

In this...