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Episode * 77 * Avg Reward is ==> -158.68906473090686
Episode * 78 * Avg Reward is ==> -164.60260866654318
Episode * 79 * Avg Reward is ==> -161.5493472156026
Episode * 80 * Avg Reward is ==> -152.48077012719403
Episode * 81 * Avg Reward is ==> -149.52532010375975
Episode * 82 * Avg Reward is ==> -149.61942419730423
Episode * 83 * Avg Reward is ==> -149.82443455067468
Episode * 84 * Avg Reward is ==> -149.80009937226978
Episode * 85 * Avg Reward is ==> -144.51659331262107
Episode * 86 * Avg Reward is ==> -150.7545561142967
Episode * 87 * Avg Reward is ==> -153.84772667131307
Episode * 88 * Avg Reward is ==> -151.35200443047225
Episode * 89 * Avg Reward is ==> -148.30392250041828
Episode * 90 * Avg Reward is ==> -151.33886235855053
Episode * 91 * Avg Reward is ==> -151.153096135589
Episode * 92 * Avg Reward is ==> -151.19626034791332
Episode * 93 * Avg Reward is ==> -151.15870791946685
Episode * 94 * Avg Reward is ==> -154.2673372216281
Episode * 95 * Avg Reward is ==> -150.40737651480134
Episode * 96 * Avg Reward is ==> -147.7969116731913
Episode * 97 * Avg Reward is ==> -147.88640802454557
Episode * 98 * Avg Reward is ==> -144.88997165191319
Episode * 99 * Avg Reward is ==> -142.22158276699662
png
If training proceeds correctly, the average episodic reward will increase with time.
Feel free to try different learning rates, tau values, and architectures for the Actor and Critic networks.
The Inverted Pendulum problem has low complexity, but DDPG work great on many other problems.
Another great environment to try this on is LunarLandingContinuous-v2, but it will take more episodes to obtain good results.
# Save the weights
actor_model.save_weights(\"pendulum_actor.h5\")
critic_model.save_weights(\"pendulum_critic.h5\")
target_actor.save_weights(\"pendulum_target_actor.h5\")
target_critic.save_weights(\"pendulum_target_critic.h5\")
Before Training:
before_img
After 100 episodes:
after_img
Play Atari Breakout with a Deep Q-Network.
Introduction
This script shows an implementation of Deep Q-Learning on the BreakoutNoFrameskip-v4 environment.
Deep Q-Learning
As an agent takes actions and moves through an environment, it learns to map the observed state of the environment to an action. An agent will choose an action in a given state based on a \"Q-value\", which is a weighted reward based on the expected highest long-term reward. A Q-Learning Agent learns to perform its task such that the recommended action maximizes the potential future rewards. This method is considered an \"Off-Policy\" method, meaning its Q values are updated assuming that the best action was chosen, even if the best action was not chosen.
Atari Breakout
In this environment, a board moves along the bottom of the screen returning a ball that will destroy blocks at the top of the screen. The aim of the game is to remove all blocks and breakout of the level. The agent must learn to control the board by moving left and right, returning the ball and removing all the blocks without the ball passing the board.
Note
The Deepmind paper trained for \"a total of 50 million frames (that is, around 38 days of game experience in total)\". However this script will give good results at around 10 million frames which are processed in less than 24 hours on a modern machine.
References
Q-Learning
Deep Q-Learning
Setup
from baselines.common.atari_wrappers import make_atari, wrap_deepmind
import numpy as np
import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers
# Configuration paramaters for the whole setup
seed = 42
gamma = 0.99 # Discount factor for past rewards
epsilon = 1.0 # Epsilon greedy parameter
epsilon_min = 0.1 # Minimum epsilon greedy parameter
epsilon_max = 1.0 # Maximum epsilon greedy parameter
epsilon_interval = (
epsilon_max - epsilon_min
) # Rate at which to reduce chance of random action being taken
batch_size = 32 # Size of batch taken from replay buffer
max_steps_per_episode = 10000
# Use the Baseline Atari environment because of Deepmind helper functions
env = make_atari(\"BreakoutNoFrameskip-v4\")
# Warp the frames, grey scale, stake four frame and scale to smaller ratio
env = wrap_deepmind(env, frame_stack=True, scale=True)
env.seed(seed)
Implement the Deep Q-Network
This network learns an approximation of the Q-table, which is a mapping between the states and actions that an agent will take. For every state we'll have four actions, that can be taken. The environment provides the state, and the action is chosen by selecting the larger of the four Q-values predicted in the output layer.
num_actions = 4
def create_q_model():
# Network defined by the Deepmind paper
inputs = layers.Input(shape=(84, 84, 4,))
# Convolutions on the frames on the screen
layer1 = layers.Conv2D(32, 8, strides=4, activation=\"relu\")(inputs)