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SAC

Implementation of Soft Actor-Critic: Off-Policy Maximum Entropy Deep Reinforcement Learning with a Stochastic Actor

Added another branch for Soft Actor-Critic Algorithms and Applications -> SAC_V1.

Soft Q-Learning uses the following objective function instead of the conventional expected cumulative return:

J( \pi ) =  \sum_{t=0}^T  E_{( s_{t},  a_{t})  \sim{  \rho _{t} }} [r(s_{t},  a_{t}) +  \alpha H(.|s_{t})]

The entropy term is also maximized which have two major benefits:
  1. The exploration will be intelligently tuned and maximized as much as need, so the exploration/exploitation trade off is well satisfied.
  2. It prevent the learning procedure to get stuck in a local optima which results to a suboptimal policy.

Demos

Humanoid-v2 Walker2d-v2 Hopper-v2

Results

Humanoid-v2 Walker2d-v2 Hopper-v2

Dependencies

  • gym == 0.17.2
  • mujoco-py == 2.0.2.13
  • numpy == 1.19.1
  • psutil == 5.4.2
  • torch == 1.4.0

Installation

pip3 install -r requirements.txt

Usage

python3 main.py
  • You may use Train flag to specify whether to train your agent when it is True or test it when the flag is False.
  • There are some pre-trained weights in pre-trained models dir, you can test the agent by using them; put them on the root folder of the project and turn Train flag to False.

Environment tested

  • Humanoid-v2
  • Hopper-v2
  • Walker2d-v2
  • HalfCheetah-v2

Reference

  1. Soft Actor-Critic: Off-Policy Maximum Entropy Deep Reinforcement Learning with a Stochastic Actor, Haarnoja et al., 2018
  2. Soft Actor-Critic Algorithms and Applications, Haarnoja et al., 2018

Acknowledgement

All credits goes to @pranz24 for his brilliant Pytorch implementation of SAC.
Special thanks to @p-christ for SAC.py

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Implementation of Soft Actor-Critic: Off-Policy Maximum Entropy Deep Reinforcement Learning with a Stochastic Actor.

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