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PyTorch 1.x Reinforcement Learning Cookbook

You're reading from   PyTorch 1.x Reinforcement Learning Cookbook Over 60 recipes to design, develop, and deploy self-learning AI models using Python

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Product type Paperback
Published in Oct 2019
Publisher Packt
ISBN-13 9781838551964
Length 340 pages
Edition 1st Edition
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Author (1):
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Yuxi (Hayden) Liu Yuxi (Hayden) Liu
Author Profile Icon Yuxi (Hayden) Liu
Yuxi (Hayden) Liu
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Table of Contents (11) Chapters Close

Preface 1. Getting Started with Reinforcement Learning and PyTorch 2. Markov Decision Processes and Dynamic Programming FREE CHAPTER 3. Monte Carlo Methods for Making Numerical Estimations 4. Temporal Difference and Q-Learning 5. Solving Multi-armed Bandit Problems 6. Scaling Up Learning with Function Approximation 7. Deep Q-Networks in Action 8. Implementing Policy Gradients and Policy Optimization 9. Capstone Project – Playing Flappy Bird with DQN 10. Other Books You May Enjoy

Implementing the actor-critic algorithm

In the REINFORCE with baseline algorithm, there are two separate components, the policy model and the value function. We can actually combine the learning of these two components, since the goal of learning the value function is to update the policy network. This is what the actor-critic algorithm does, and which we are going to develop in this recipe.

The network for the actor-critic algorithm consists of the following two parts:

  • Actor: This takes in the input state and outputs the action probabilities. Essentially, it learns the optimal policy by updating the model using information provided by the critic.
  • Critic: This evaluates how good it is to be at the input state by computing the value function. The value guides the actor on how it should adjust.

These two components share parameters of input and hidden layers in the network, as...

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