写一个python程序使用DQN的方法解决CartPole-V0问题,使用英文注释
时间: 2024-01-29 21:02:43 浏览: 124
基于Python的DQN 强化学习项目
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Sure, I can help you with that. Here is the Python program that uses DQN method to solve CartPole-V0 problem:
```
import gym
import random
import numpy as np
from collections import deque
from keras.models import Sequential
from keras.layers import Dense
from keras.optimizers import Adam
EPISODES = 1000
MEMORY_SIZE = 1000000
BATCH_SIZE = 20
GAMMA = 0.95
EPSILON = 1.0
EPSILON_MIN = 0.01
EPSILON_DECAY = 0.995
LEARNING_RATE = 0.001
class DQNAgent:
def __init__(self, state_size, action_size):
self.state_size = state_size
self.action_size = action_size
self.memory = deque(maxlen=MEMORY_SIZE)
self.epsilon = EPSILON
self.model = self.build_model()
def build_model(self):
# Neural network with two hidden layers
model = Sequential()
model.add(Dense(24, input_dim=self.state_size, activation='relu'))
model.add(Dense(24, activation='relu'))
model.add(Dense(self.action_size, activation='linear'))
model.compile(loss='mse', optimizer=Adam(lr=LEARNING_RATE))
return model
def remember(self, state, action, reward, next_state, done):
self.memory.append((state, action, reward, next_state, done))
def act(self, state):
if np.random.rand() <= self.epsilon:
# Exploration
return random.randrange(self.action_size)
# Exploitation
return np.argmax(self.model.predict(state)[0])
def replay(self, batch_size):
if len(self.memory) < batch_size:
return
# Sample batch from memory
minibatch = random.sample(self.memory, batch_size)
# Train the neural network
for state, action, reward, next_state, done in minibatch:
target = reward
if not done:
target = reward + GAMMA * np.amax(self.model.predict(next_state)[0])
q_values = self.model.predict(state)
q_values[0][action] = target
self.model.fit(state, q_values, verbose=0)
# Update exploration rate
if self.epsilon > EPSILON_MIN:
self.epsilon *= EPSILON_DECAY
if __name__ == "__main__":
env = gym.make('CartPole-v0')
state_size = env.observation_space.shape[0]
action_size = env.action_space.n
agent = DQNAgent(state_size, action_size)
for episode in range(EPISODES):
state = env.reset()
state = np.reshape(state, [1, state_size])
done = False
score = 0
while not done:
action = agent.act(state)
next_state, reward, done, _ = env.step(action)
next_state = np.reshape(next_state, [1, state_size])
agent.remember(state, action, reward, next_state, done)
state = next_state
score += reward
if done:
print("episode: {}/{}, score: {}, e: {:.2}".format(episode, EPISODES, score, agent.epsilon))
agent.replay(BATCH_SIZE)
```
此代码用到了深度神经网络以及记忆回放技术,来训练 CartPole-v0 问题的解决。神经网络使用了两个隐藏层,每个隐藏层有 24 个神经元,以及一个线性输出层。神经网络使用的损失函数是均方误差,使用的优化器是 Adam。在训练过程中,每个 episode 中的状态被存储到记忆体中,然后从记忆体中随机取出一部分小批量来训练神经网络。每个动作的 Q 值由神经网络给出,然后使用 Bellman 公式来更新 Q 值。在训练完一次神经网络后,更新探索率。
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