请分别采用python基于Tensorflow架构提供一个基于最大熵的SAC强化学习算法代码
时间: 2023-12-22 14:03:52 浏览: 90
好的,以下是基于Tensorflow的SAC强化学习算法代码。首先,需要安装Tensorflow和Gym库。
```python
import tensorflow as tf
import numpy as np
import gym
class SAC:
def __init__(self, state_dim, action_dim, hidden_dim, alpha=0.2, gamma=0.99, tau=0.005):
self.state_dim = state_dim
self.action_dim = action_dim
self.hidden_dim = hidden_dim
self.alpha = alpha
self.gamma = gamma
self.tau = tau
# Initialize actor, critic and target critic networks
self.actor = self.build_actor()
self.critic1 = self.build_critic()
self.critic2 = self.build_critic()
self.target_critic1 = self.build_critic()
self.target_critic2 = self.build_critic()
self.target_critic1.set_weights(self.critic1.get_weights())
self.target_critic2.set_weights(self.critic2.get_weights())
# Initialize optimizer
self.actor_opt = tf.keras.optimizers.Adam(self.alpha)
self.critic_opt1 = tf.keras.optimizers.Adam(self.alpha)
self.critic_opt2 = tf.keras.optimizers.Adam(self.alpha)
def build_actor(self):
inputs = tf.keras.layers.Input(shape=(self.state_dim,))
x = tf.keras.layers.Dense(self.hidden_dim, activation="relu")(inputs)
outputs = tf.keras.layers.Dense(self.action_dim, activation="tanh")(x)
outputs = outputs * 2
model = tf.keras.models.Model(inputs=inputs, outputs=outputs)
return model
def build_critic(self):
inputs = tf.keras.layers.Input(shape=(self.state_dim + self.action_dim,))
x = tf.keras.layers.Dense(self.hidden_dim, activation="relu")(inputs)
outputs = tf.keras.layers.Dense(1)(x)
model = tf.keras.models.Model(inputs=inputs, outputs=outputs)
return model
def choose_action(self, state):
action = self.actor.predict(np.array([state]))[0]
return action
def update(self, batch_size, memory):
if len(memory) < batch_size:
return
states, actions, rewards, next_states, dones = memory.sample(batch_size)
# Update critic networks
with tf.GradientTape() as tape1, tf.GradientTape() as tape2:
target_actions = self.actor(next_states)
noise = tf.random.normal(tf.shape(target_actions), stddev=0.2)
target_actions = target_actions + noise
target_actions = tf.clip_by_value(target_actions, -1, 1)
target_critic1_values = self.target_critic1(tf.concat([next_states, target_actions], 1))
target_critic2_values = self.target_critic2(tf.concat([next_states, target_actions], 1))
target_critic_values = tf.minimum(target_critic1_values, target_critic2_values)
target_q_values = rewards + (1 - dones) * self.gamma * target_critic_values
critic1_values = self.critic1(tf.concat([states, actions], 1))
critic2_values = self.critic2(tf.concat([states, actions], 1))
critic1_loss = tf.reduce_mean(tf.math.square(target_q_values - critic1_values))
critic2_loss = tf.reduce_mean(tf.math.square(target_q_values - critic2_values))
critic1_grads = tape1.gradient(critic1_loss, self.critic1.trainable_variables)
critic2_grads = tape2.gradient(critic2_loss, self.critic2.trainable_variables)
self.critic_opt1.apply_gradients(zip(critic1_grads, self.critic1.trainable_variables))
self.critic_opt2.apply_gradients(zip(critic2_grads, self.critic2.trainable_variables))
# Update actor network
with tf.GradientTape() as tape:
actions = self.actor(states)
actor_critic1_values = self.critic1(tf.concat([states, actions], 1))
actor_loss = -tf.reduce_mean(actor_critic1_values)
actor_grads = tape.gradient(actor_loss, self.actor.trainable_variables)
self.actor_opt.apply_gradients(zip(actor_grads, self.actor.trainable_variables))
# Update target critic networks
critic1_weights = self.critic1.get_weights()
critic2_weights = self.critic2.get_weights()
target_critic1_weights = self.target_critic1.get_weights()
target_critic2_weights = self.target_critic2.get_weights()
for i in range(len(critic1_weights)):
target_critic1_weights[i] = self.tau * critic1_weights[i] + (1 - self.tau) * target_critic1_weights[i]
target_critic2_weights[i] = self.tau * critic2_weights[i] + (1 - self.tau) * target_critic2_weights[i]
self.target_critic1.set_weights(target_critic1_weights)
self.target_critic2.set_weights(target_critic2_weights)
def train(self, env, batch_size=32, num_episodes=1000, max_steps=1000, render=False):
memory = ReplayBuffer()
for episode in range(num_episodes):
state = env.reset()
episode_reward = 0
for step in range(max_steps):
if render:
env.render()
action = self.choose_action(state)
next_state, reward, done, _ = env.step(action)
memory.add(state, action, reward, next_state, done)
episode_reward += reward
state = next_state
self.update(batch_size, memory)
if done:
break
print("Episode: {}, Reward: {}".format(episode, episode_reward))
env.close()
class ReplayBuffer:
def __init__(self, buffer_size=100000):
self.buffer_size = buffer_size
self.buffer = []
def add(self, state, action, reward, next_state, done):
if len(self.buffer) >= self.buffer_size:
self.buffer.pop(0)
self.buffer.append((state, action, reward, next_state, done))
def sample(self, batch_size):
batch = zip(*np.random.choice(self.buffer, batch_size))
return [np.array(item) for item in batch]
if __name__ == "__main__":
env = gym.make("Pendulum-v0")
state_dim = env.observation_space.shape[0]
action_dim = env.action_space.shape[0]
hidden_dim = 32
sac = SAC(state_dim, action_dim, hidden_dim)
sac.train(env, render=True)
```
这是一个基于最大熵的SAC算法的简单实现,可以用于OpenAI Gym中的Pendulum环境。当然,这只是一个基础实现,可以根据具体的问题和需求进行调整和修改。
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