写一个python程序使用DQN的方法解决CartPole-V0问题,使用英文注释,不使用keras
时间: 2024-05-14 18:17:02 浏览: 126
用matlab自主搭建DQN算法解决CartPole问题
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Sure, I can help you with that! Here is a simple Python program using the DQN method to solve the CartPole-V0 problem. This program does not use Keras and has English comments to help you understand what's happening.
First, we'll import the necessary libraries:
```python
import random
import numpy as np
import tensorflow as tf
import gym
```
Next, we'll set up our parameters:
```python
# Define some hyperparameters
batch_size = 32 # How many memory samples to train on
replay_memory_size = 10000 # How many recent frames to remember
gamma = 0.99 # Discount rate for future rewards
n_episodes = 5000 # How many episodes to train for
n_steps = 200 # Maximum number of steps in each episode
start_epsilon = 1.0 # Initial value of epsilon for epsilon-greedy exploration
end_epsilon = 0.05 # Final value of epsilon for epsilon-greedy exploration
epsilon_decay_steps = 10000 # Number of steps to decay epsilon from start to end value
learning_rate = 0.001 # Learning rate for the neural network optimizer
```
Now we can define our neural network:
```python
# Define the neural network
n_inputs = 4 # Number of input features (four observations from the environment)
n_hidden = 32 # Number of hidden neurons in the network
n_outputs = 2 # Number of output neurons (actions: move left or right)
initializer = tf.random_normal_initializer()
# Define the input and output placeholders
tf.reset_default_graph()
X = tf.placeholder(tf.float32, shape=[None, n_inputs])
y = tf.placeholder(tf.float32, shape=[None, n_outputs])
# Define the network architecture
hidden = tf.layers.dense(X, n_hidden, activation=tf.nn.relu, kernel_initializer=initializer)
logits = tf.layers.dense(hidden, n_outputs, kernel_initializer=initializer)
# Define the loss function and optimizer
cross_entropy = tf.nn.softmax_cross_entropy_with_logits_v2(labels=y, logits=logits)
optimizer = tf.train.AdamOptimizer(learning_rate)
training_op = optimizer.minimize(cross_entropy)
# Define the prediction and exploration functions
predict_op = tf.argmax(logits, axis=1)
exploration_op = tf.random_uniform(tf.shape(logits))
```
Next, we'll define our memory and exploration strategies:
```python
# Define the memory and exploration strategies
replay_memory = []
def sample_memories(batch_size):
indices = np.random.permutation(len(replay_memory))[:batch_size]
cols = [[], [], [], [], []] # state, action, reward, next_state, done
for index in indices:
memory = replay_memory[index]
for col, value in zip(cols, memory):
col.append(value)
cols = [np.array(col) for col in cols]
return (cols[0], cols[1], cols[2].reshape(-1, 1), cols[3], cols[4].reshape(-1, 1))
epsilon = start_epsilon
def explore(state, step):
if step < epsilon_decay_steps:
epsilon = start_epsilon - step / epsilon_decay_steps * (start_epsilon - end_epsilon)
else:
epsilon = end_epsilon
if np.random.rand() < epsilon:
return np.random.randint(n_outputs)
else:
return predict_op.eval(feed_dict={X: state.reshape(1, n_inputs)})
```
Now we're ready to start training:
```python
# Start training
env = gym.make("CartPole-v0")
with tf.Session() as sess:
tf.global_variables_initializer().run()
for episode in range(n_episodes):
# Reset the environment
obs = env.reset()
for step in range(n_steps):
# Explore the environment
action = explore(obs, step)
next_obs, reward, done, _ = env.step(action)
# Store the experience in replay memory
replay_memory.append((obs, action, reward, next_obs, done))
obs = next_obs
# Sample a random batch of experiences from replay memory
X_state_val, X_action_val, rewards, X_next_state_val, dones = (sample_memories(batch_size))
# Compute the TD target
next_q_values = logits.eval(feed_dict={X: X_next_state_val})
max_next_q_values = np.max(next_q_values, axis=1, keepdims=True)
# Compute the training targets
y_val = rewards + (1 - dones) * gamma * max_next_q_values
# Train the network on a batch of experiences
training_op.run(feed_dict={X: X_state_val, y: y_val})
# Every 50 episodes, print the episode number and average reward
if episode % 50 == 0:
total_reward = 0
obs = env.reset()
for i in range(n_steps):
action = predict_op.eval(feed_dict={X: obs.reshape(1, n_inputs)})
obs, reward, done, _ = env.step(action)
total_reward += reward
if done:
break
print("Episode:", episode, " Reward:", total_reward)
```
And that's it! This program should train a neural network using the DQN method to solve the CartPole-V0 problem, and print the episode number and average reward every 50 episodes. Let me know if you have any questions or if there's anything else I can help you with!
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