请采用python以Tensorflow为架构编写一个包含1个actor网络,2个V Critic网络(1个V Critic网络,1个Target V Critic网络),2个Q Critic网络版本的SAC强化学习算法代码
时间: 2024-02-11 20:04:47 浏览: 77
很高兴为您提供代码,由于代码长度较长,我将提供主要代码和注释,以方便您了解实现方法。请注意,该代码可能需要根据您的具体应用进行修改。
```python
import tensorflow as tf
from tensorflow.keras import layers
import numpy as np
class SAC:
def __init__(self, state_dim, action_dim, max_action):
self.state_dim = state_dim
self.action_dim = action_dim
self.max_action = max_action
self.actor = self.create_actor_model()
self.v_critic = self.create_v_critic_model()
self.target_v_critic = self.create_v_critic_model()
self.q_critic_1 = self.create_q_critic_model()
self.q_critic_2 = self.create_q_critic_model()
self.target_v_critic.set_weights(self.v_critic.get_weights())
self.actor_optimizer = tf.keras.optimizers.Adam(learning_rate=0.0003)
self.v_critic_optimizer = tf.keras.optimizers.Adam(learning_rate=0.0003)
self.q_critic_1_optimizer = tf.keras.optimizers.Adam(learning_rate=0.0003)
self.q_critic_2_optimizer = tf.keras.optimizers.Adam(learning_rate=0.0003)
def create_actor_model(self):
state_input = layers.Input(shape=(self.state_dim,))
x = layers.Dense(256, activation="relu")(state_input)
x = layers.Dense(256, activation="relu")(x)
action_output = layers.Dense(self.action_dim, activation="tanh")(x)
actor = tf.keras.Model(state_input, action_output)
return actor
def create_v_critic_model(self):
state_input = layers.Input(shape=(self.state_dim,))
x = layers.Dense(256, activation="relu")(state_input)
x = layers.Dense(256, activation="relu")(x)
v_output = layers.Dense(1)(x)
v_critic = tf.keras.Model(state_input, v_output)
return v_critic
def create_q_critic_model(self):
state_input = layers.Input(shape=(self.state_dim,))
action_input = layers.Input(shape=(self.action_dim,))
x = layers.concatenate([state_input, action_input])
x = layers.Dense(256, activation="relu")(x)
x = layers.Dense(256, activation="relu")(x)
q_output = layers.Dense(1)(x)
q_critic = tf.keras.Model([state_input, action_input], q_output)
return q_critic
def select_action(self, state):
state = np.array(state)
state = tf.convert_to_tensor([state], dtype=tf.float32)
action = self.actor(state)
return action.numpy()[0]
def train(self, replay_buffer, batch_size=64, discount=0.99, tau=0.005, alpha=0.2):
# Sample a batch of transitions
state_batch, action_batch, next_state_batch, reward_batch, done_batch = replay_buffer.sample(batch_size)
# Update V Critic network
with tf.GradientTape() as tape:
target_v = self.target_v_critic(next_state_batch)
target_q = reward_batch + (1 - done_batch) * discount * target_v
v_values = self.v_critic(state_batch)
v_loss = tf.keras.losses.MSE(target_q, v_values)
v_grads = tape.gradient(v_loss, self.v_critic.trainable_variables)
self.v_critic_optimizer.apply_gradients(zip(v_grads, self.v_critic.trainable_variables))
# Update Q Critic networks
with tf.GradientTape(persistent=True) as tape:
q1_values = self.q_critic_1([state_batch, action_batch])
q2_values = self.q_critic_2([state_batch, action_batch])
next_action = self.actor(next_state_batch)
next_q1_values = self.q_critic_1([next_state_batch, next_action])
next_q2_values = self.q_critic_2([next_state_batch, next_action])
target_q = tf.minimum(next_q1_values, next_q2_values)
target_q = tf.stop_gradient(reward_batch + (1 - done_batch) * discount * target_q)
q1_loss = tf.keras.losses.MSE(target_q, q1_values)
q2_loss = tf.keras.losses.MSE(target_q, q2_values)
q1_grads = tape.gradient(q1_loss, self.q_critic_1.trainable_variables)
q2_grads = tape.gradient(q2_loss, self.q_critic_2.trainable_variables)
self.q_critic_1_optimizer.apply_gradients(zip(q1_grads, self.q_critic_1.trainable_variables))
self.q_critic_2_optimizer.apply_gradients(zip(q2_grads, self.q_critic_2.trainable_variables))
# Update Actor network
with tf.GradientTape() as tape:
new_action = self.actor(state_batch)
new_q1_values = self.q_critic_1([state_batch, new_action])
actor_loss = -tf.reduce_mean(new_q1_values)
actor_grads = tape.gradient(actor_loss, self.actor.trainable_variables)
self.actor_optimizer.apply_gradients(zip(actor_grads, self.actor.trainable_variables))
# Update Target V Critic network
v_weights = self.v_critic.get_weights()
target_v_weights = self.target_v_critic.get_weights()
for i in range(len(v_weights)):
target_v_weights[i] = tau * v_weights[i] + (1 - tau) * target_v_weights[i]
self.target_v_critic.set_weights(target_v_weights)
```
这是SAC算法的主要代码。在这个类中,我们首先定义了四个神经网络,包括一个Actor网络、两个V Critic网络(一个V Critic网络和一个Target V Critic网络)、两个Q Critic网络。然后我们定义了一些用于训练网络的优化器和超参数,例如学习率、批量大小、折扣因子等。
在程序的主循环中,我们首先从经验池中选择一个随机批次的转换,然后在V Critic网络中使用随机批次的下一个状态来计算目标V值,然后使用MSE损失函数来计算V Critic网络的损失,然后使用梯度下降来更新V Critic网络的权重。接下来,我们使用Q Critic网络计算当前状态和动作的Q值,然后使用Actor网络计算下一个状态的动作,然后使用Q Critic网络计算下一个状态和下一个动作的Q值。然后我们根据两个Q值的最小值计算目标Q值,并使用MSE损失函数更新两个Q Critic网络的权重。接下来,我们使用Actor网络计算当前状态的新动作,并使用Q Critic网络计算新动作的Q值。我们使用负的Q值来计算Actor网络的损失,并使用梯度下降算法来更新Actor网络的权重。最后,我们使用Polyak平均法来更新Target V Critic网络的权重。
这就是一个简单的SAC算法的实现。请注意,这只是一个基本的实现,您可以通过修改超参数和网络架构来改善它的性能。
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