PER-DQN是什么
时间: 2023-12-24 20:24:46 浏览: 152
根据提供的引用内容,没有直接提到PER-DQN。但是可以根据引用中提到的Ensemble-DQN和Averaged-DQN来推测PER-DQN的含义。PER-DQN是Prioritized Experience Replay Deep Q-Network的缩写,是一种基于经验回放的深度强化学习算法。与传统的DQN算法不同,PER-DQN使用优先级队列来存储经验,以便更有效地学习重要的经验。在PER-DQN中,经验被赋予不同的优先级,优先级高的经验被更频繁地抽样以便更好地学习。因此,PER-DQN在学习效率和性能方面优于传统的DQN算法。
相关问题
dqn python代码
以下是DQN算法的Python实现(使用TensorFlow):
```python
import tensorflow as tf
import numpy as np
import gym
# 创建游戏环境
env = gym.make('CartPole-v0')
# 定义超参数
learning_rate = 0.01
discount_factor = 0.99
batch_size = 64
memory_size = 10000
epsilon = 1.0
epsilon_decay = 0.9995
min_epsilon = 0.01
n_episodes = 2000
n_steps_per_episode = 200
update_target_network_every = 100
# 创建经验回放存储器
memory = []
# 定义神经网络
class DQN(tf.keras.Model):
def __init__(self, n_actions):
super(DQN, self).__init__()
self.dense1 = tf.keras.layers.Dense(32, activation='relu')
self.dense2 = tf.keras.layers.Dense(32, activation='relu')
self.dense3 = tf.keras.layers.Dense(n_actions)
def call(self, inputs):
x = self.dense1(inputs)
x = self.dense2(x)
x = self.dense3(x)
return x
# 创建主网络和目标网络
n_actions = env.action_space.n
main_network = DQN(n_actions)
target_network = DQN(n_actions)
target_network.set_weights(main_network.get_weights())
# 定义损失函数和优化器
loss_fn = tf.keras.losses.MeanSquaredError()
optimizer = tf.keras.optimizers.Adam(learning_rate=learning_rate)
# 定义动作选择策略
def choose_action(state, epsilon):
if np.random.rand() < epsilon:
return env.action_space.sample()
else:
Q_values = main_network(tf.constant([state], dtype=tf.float32)).numpy()[0]
return np.argmax(Q_values)
# 从经验回放存储器中随机采样一个批次进行训练
def train():
batch = np.array(memory)[np.random.choice(len(memory), batch_size, replace=False)]
states = np.array([b[0] for b in batch])
actions = np.array([b[1] for b in batch])
rewards = np.array([b[2] for b in batch])
next_states = np.array([b[3] for b in batch])
dones = np.array([b[4] for b in batch])
Q_values_next = target_network(next_states).numpy()
Q_values_target = rewards + discount_factor * np.max(Q_values_next, axis=1) * (1 - dones)
Q_values = main_network(states).numpy()
Q_values[np.arange(batch_size), actions] = Q_values_target
with tf.GradientTape() as tape:
loss = loss_fn(Q_values, main_network(states))
grads = tape.gradient(loss, main_network.trainable_variables)
optimizer.apply_gradients(zip(grads, main_network.trainable_variables))
# 训练主网络
total_reward_history = []
for episode in range(n_episodes):
state = env.reset()
total_reward = 0
for step in range(n_steps_per_episode):
epsilon = max(epsilon * epsilon_decay, min_epsilon)
action = choose_action(state, epsilon)
next_state, reward, done, _ = env.step(action)
memory.append((state, action, reward, next_state, done))
total_reward += reward
state = next_state
if len(memory) > memory_size:
memory.pop(0)
if episode % update_target_network_every == 0:
target_network.set_weights(main_network.get_weights())
if done:
break
if len(memory) > batch_size:
train()
total_reward_history.append(total_reward)
print(f'Episode {episode} completed with total reward of {total_reward}.')
```
dqn算法matlab代码
以下是DQN算法的Matlab代码,用于实现深度强化学习的智能体训练:
```matlab
% DQN Algorithm
% Initialize replay memory D
D = [];
% Initialize Q-network with random weights
Q = randn(inputSize, numActions);
% Initialize target Q-network with same weights as Q-network
QTarget = Q;
% Initialize action selection parameters
epsilon = 1; % exploration rate
minEpsilon = 0.1; % minimum exploration rate
epsilonDecayRate = 0.0001; % exploration rate decay rate
% Initialize other hyperparameters
batchSize = 32; % minibatch size
gamma = 0.99; % discount factor
maxSteps = 10000; % maximum number of steps per episode
% Start training
for episode = 1:numEpisodes
% Initialize state
state = env.reset();
% Initialize episode variables
totalReward = 0;
step = 0;
% Loop over steps in episode
while step < maxSteps
% Choose action according to epsilon-greedy policy
if rand() < epsilon
action = randi(numActions);
else
[~, action] = max(Q(state,:));
end
% Take action and observe next state and reward
[nextState, reward, done] = env.step(action);
% Store transition in replay memory
D = [D; state, action, reward, nextState, done];
% Update state and total reward
state = nextState;
totalReward = totalReward + reward;
% Sample minibatch from replay memory
minibatch = D(randi(size(D,1),batchSize,1),:);
% Compute target Q-values
targetQ = minibatch(:,3) + gamma*max(QTarget(minibatch(:,4),:),[],2).*(~minibatch(:,5));
% Compute predicted Q-values
predictedQ = Q(minibatch(:,1),minibatch(:,2));
% Compute loss and update Q-network
loss = mean((targetQ - predictedQ).^2);
Q(minibatch(:,1),minibatch(:,2)) = Q(minibatch(:,1),minibatch(:,2)) + alpha*(targetQ - predictedQ);
% Update target Q-network every C steps
if mod(step,C) == 0
QTarget = Q;
end
% Decay exploration rate
epsilon = max(minEpsilon, epsilon - epsilonDecayRate);
% Check if episode is done
if done
break;
end
% Increment step counter
step = step + 1;
end
% Print episode statistics
fprintf('Episode %d: total reward = %.2f, epsilon = %.2f\n', episode, totalReward, epsilon);
end
```
请注意,这只是一个示例代码,您需要根据您自己的环境和要解决的问题进行适当修改。
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