基于 Hands-on-RL/第12章-PPO算法.ipynb at main · boyu-ai/Hands-on-RL · GitHub
理论 PPO 算法
修改了警告和报错
运行环境
Debian GNU/Linux 12
Python 3.9.19
torch 2.0.1
gym 0.26.2
运行代码
python
#!/usr/bin/env python
import gym
import torch
import torch.nn.functional as F
import numpy as np
import matplotlib.pyplot as plt
import rl_utils
class ValueNet(torch.nn.Module):
def __init__(self, state_dim, hidden_dim):
super(ValueNet, self).__init__()
self.fc1 = torch.nn.Linear(state_dim, hidden_dim)
self.fc2 = torch.nn.Linear(hidden_dim, 1)
def forward(self, x):
x = F.relu(self.fc1(x))
return self.fc2(x)
class PolicyNetContinuous(torch.nn.Module):
def __init__(self, state_dim, hidden_dim, action_dim):
super(PolicyNetContinuous, self).__init__()
self.fc1 = torch.nn.Linear(state_dim, hidden_dim)
self.fc_mu = torch.nn.Linear(hidden_dim, action_dim)
self.fc_std = torch.nn.Linear(hidden_dim, action_dim)
def forward(self, x):
x = F.relu(self.fc1(x))
mu = 2.0 * torch.tanh(self.fc_mu(x))
std = F.softplus(self.fc_std(x))
return mu, std
class PPOContinuous:
''' 处理连续动作的PPO算法 '''
def __init__(self, state_dim, hidden_dim, action_dim, actor_lr, critic_lr,
lmbda, epochs, eps, gamma, device):
self.actor = PolicyNetContinuous(state_dim, hidden_dim,
action_dim).to(device)
self.critic = ValueNet(state_dim, hidden_dim).to(device)
self.actor_optimizer = torch.optim.Adam(self.actor.parameters(),
lr=actor_lr)
self.critic_optimizer = torch.optim.Adam(self.critic.parameters(),
lr=critic_lr)
self.gamma = gamma
self.lmbda = lmbda
self.epochs = epochs
self.eps = eps
self.device = device
def take_action(self, state):
state = torch.tensor(np.array([state]), dtype=torch.float).to(self.device)
mu, sigma = self.actor(state)
action_dist = torch.distributions.Normal(mu, sigma)
action = action_dist.sample()
return [action.item()]
def update(self, transition_dict):
states = torch.tensor(np.array(transition_dict['states']),
dtype=torch.float).to(self.device)
actions = torch.tensor(transition_dict['actions'],
dtype=torch.float).view(-1, 1).to(self.device)
rewards = torch.tensor(transition_dict['rewards'],
dtype=torch.float).view(-1, 1).to(self.device)
next_states = torch.tensor(np.array(transition_dict['next_states']),
dtype=torch.float).to(self.device)
dones = torch.tensor(transition_dict['dones'],
dtype=torch.float).view(-1, 1).to(self.device)
rewards = (rewards + 8.0) / 8.0 # 和TRPO一样,对奖励进行修改,方便训练
td_target = rewards + self.gamma * self.critic(next_states) * (1 -
dones)
td_delta = td_target - self.critic(states)
advantage = rl_utils.compute_advantage(self.gamma, self.lmbda,
td_delta.cpu()).to(self.device)
mu, std = self.actor(states)
action_dists = torch.distributions.Normal(mu.detach(), std.detach())
# 动作是正态分布
old_log_probs = action_dists.log_prob(actions)
for _ in range(self.epochs):
mu, std = self.actor(states)
action_dists = torch.distributions.Normal(mu, std)
log_probs = action_dists.log_prob(actions)
ratio = torch.exp(log_probs - old_log_probs)
surr1 = ratio * advantage
surr2 = torch.clamp(ratio, 1 - self.eps, 1 + self.eps) * advantage
actor_loss = torch.mean(-torch.min(surr1, surr2))
critic_loss = torch.mean(
F.mse_loss(self.critic(states), td_target.detach()))
self.actor_optimizer.zero_grad()
self.critic_optimizer.zero_grad()
actor_loss.backward()
critic_loss.backward()
self.actor_optimizer.step()
self.critic_optimizer.step()
actor_lr = 1e-4
critic_lr = 5e-3
num_episodes = 2000
hidden_dim = 128
gamma = 0.9
lmbda = 0.9
epochs = 10
eps = 0.2
device = torch.device("cuda") if torch.cuda.is_available() else torch.device(
"cpu")
env_name = 'Pendulum-v1'
env = gym.make(env_name)
env.reset(seed=0)
torch.manual_seed(0)
state_dim = env.observation_space.shape[0]
action_dim = env.action_space.shape[0] # 连续动作空间
agent = PPOContinuous(state_dim, hidden_dim, action_dim, actor_lr, critic_lr,
lmbda, epochs, eps, gamma, device)
return_list = rl_utils.train_on_policy_agent(env, agent, num_episodes)
episodes_list = list(range(len(return_list)))
plt.plot(episodes_list, return_list)
plt.xlabel('Episodes')
plt.ylabel('Returns')
plt.title('PPO on {}'.format(env_name))
plt.show()
mv_return = rl_utils.moving_average(return_list, 21)
plt.plot(episodes_list, mv_return)
plt.xlabel('Episodes')
plt.ylabel('Returns')
plt.title('PPO on {}'.format(env_name))
plt.show()rl_utils.py 参考