对于之前提到的DQN模型, 损失函数使用的
Q(state) = reward + Q(nextState)max
Q(state)由训练网络生成, Q(nextState)max由目标网络生成
这种损失函数会存在问题，即当Q(nextState)max总是大于0时，那么Q(state)总是在不停的增大，同时Q(nextState)max也在不断的增大, 即Q(state)存在被高估的情况
Double DQN的解决方法是，由Q(nextstate)训练网络来决定方向，由Q(nextState)目标网络来决定Qvalue的数值, 方向来获取目标函数的数值
max_action = self.q_net(next_states).max(1)[1].view(-1, 1) # 训练函数 max_next_q_values = self.target_q_net(next_states).gather(1, max_action) # 目标函数
场景: 倒立摆的环境, 一共11个动作，动作[0,1,2,3,...9,10], 需要转换为力矩[-2, -1.6, -1.2, ....1.2, 1.6, 2] 转化成离散的, 因为DQN只能处理离散的数据
train.py
import random
import gym
import numpy as np
import collections
import torch
import torch.nn.functional as F
import matplotlib.pyplot as plt
from tqdm import tqdm
from model import DQN
import rl_utils
from rl_utils import ReplayBuffer
lr = 1e-2 # 学习率
num_episodes = 200 #迭代次数
hidden_dim = 128 #隐藏层
gamma = 0.98
epsilon = 0.01
target_update = 50
batch_size = 64
device = torch.device("cuda") if torch.cuda.is_available() else torch.device('cpu')
buffer_size = 5000 # 观察数据的数量
minimal_size = 1000
replay_buffer = ReplayBuffer(buffer_size)
env_name = "Pendulum-v0"
env = gym.make(env_name)
state_dim = env.observation_space.shape[0] # 这里的输入是4个变量 速度, 位置, 尖端速度, 杆的角度
action_dim = 11
def dis_to_con(disrete_action, env, action_dim):
action_lowbound = env.action_space.low[0]
action_upbound = env.action_space.high[0]
return action_lowbound + (disrete_action / (action_dim - 1)) * (action_upbound - action_lowbound)
def train_DQN(agent, env, num_episodes, replay_buffer, minimal_size,
batch_size):
return_list = []
max_q_value_list = []
max_q_value = 0
for i in range(10):
with tqdm(total=int(num_episodes / 10), desc='Iteration %d' % i) as pbar:
for i_episode in range(int(num_episodes/10)):
episode_return = 0
state = env.reset()
done = False
while not done:
action = agent.take_action(state)
# 使用累计来表示max_q_value
max_q_value = agent.max_q_value(
state) * 0.005 + max_q_value * 0.995
max_q_value_list.append(max_q_value)
action_continuous = dis_to_con(action, env, agent.action_dim) # 将角度转换为离散数据
next_state, reward, done, _ = env.step([action_continuous]) # 将角度输入到环境中获得下一个状态, 奖励, 是否停止
replay_buffer.add(state, action, reward, next_state, done) # 加入到缓冲区
state = next_state
episode_return += reward
# 当buffer的数量超过一定数量的时候, 进行Q网络训练
if replay_buffer.size() > minimal_size:
b_s, b_a, b_r, b_ns, b_d = replay_buffer.sample(batch_size=batch_size) # 从缓冲区取数据
transition_dict = {
'states':b_s,
'actions':b_a,
'next_states':b_ns,
'rewards': b_r,
'dones': b_d,
}
agent.update(transition_dict) # 更新网络
return_list.append(episode_return)
if (i_episode + 1) % 10 == 0:
pbar.set_postfix({
'episode':
'%d' % (num_episodes / 10 * i + i_episode),
'return':
'%.3f' % np.mean(return_list[-10:])
})
pbar.update(1)
return return_list, max_q_value_list
agent = DQN(state_dim, hidden_dim, action_dim, lr,
gamma, epsilon, target_update, device)
return_list, max_q_value_list = train_DQN(agent, env, num_episodes, replay_buffer, minimal_size,
batch_size)
episodes_list = list(range(len(return_list)))
plt.plot(episodes_list, return_list)
plt.xlabel('Episodes')
plt.ylabel('Returns')
plt.title('DQN on {}'.format(env_name))
plt.show()
frames_list = list(range(len(max_q_value_list)))
plt.plot(frames_list, max_q_value_list)
plt.axhline(0, c='orange', ls='--')
plt.axhline(10, c='red', ls='--')
plt.xlabel('Frames')
plt.ylabel('Q value')
plt.title('DQN on {}'.format(env_name))
plt.show()
model.py
import numpy as np
import torch.nn
import torch.nn.functional as F
class Qnet(torch.nn.Module):
'''只有一层的隐藏层的Q网络'''
def __init__(self, state_dim, hidden_dim, action_dim):
super(Qnet, self).__init__()
self.fc1 = torch.nn.Linear(state_dim, hidden_dim)
self.fc2 = torch.nn.Linear(hidden_dim, action_dim)
def forward(self, x):
x = F.relu(self.fc1(x))
return self.fc2(x)
class DQN:
"""DQN算法"""
def __init__(self, state_dim, hidden_dim, action_dim, learning_rate,
gamma, epsilon, target_update, device, dqn_type="DoubleDQN_dim"):
self.action_dim = action_dim
self.q_net = Qnet(state_dim, hidden_dim,
self.action_dim).to(device)
# 目标网络
self.target_q_net = Qnet(state_dim, hidden_dim,
self.action_dim).to(device)
#使用Adam优化器
self.optimizer = torch.optim.Adam(self.q_net.parameters(),
lr=learning_rate)
self.gamma = gamma # 折扣因子
self.epsilon = epsilon # epsilon-贪婪策略
self.target_update = target_update # 目标网络更新频率
self.count = 0 #计数器,记录更新次数
self.device = device
self.dqn_type = dqn_type
'''输入到模型获得动作, 使用的epsilon'''
def take_action(self, state):
if np.random.random() < self.epsilon:
action = np.random.randint(self.action_dim)
else:
state = torch.tensor([state], dtype=torch.float).to(self.device)
action = self.q_net(state).argmax().item() # item表示实际的数据
return action
'''用来更新网络参数'''
def update(self, transition_dict):
states = torch.tensor(transition_dict['states'],
dtype=torch.float).to(self.device)
actions = torch.tensor(transition_dict['actions']).view(-1, 1).to(self.device)
rewards = torch.tensor(transition_dict['rewards'],
dtype=torch.float).to(self.device)
next_states = torch.tensor(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)
q_values = self.q_net(states).gather(1, actions) # 获得对应动作的Q值
# 下一个状态的最大Q值
if self.dqn_type == "DoubleDQN":
max_action = self.q_net(next_states).max(1)[1].view(-1, 1)
max_next_q_values = self.target_q_net(next_states).gather(1, max_action)
else:
max_next_q_values = self.target_q_net(next_states).max(1)[0].view(-1, 1)
q_target = rewards + self.gamma * max_next_q_values
dqn_loss = torch.mean(F.mse_loss(q_values, q_target))
self.optimizer.zero_grad()
dqn_loss.backward()
self.optimizer.step()
if self.count % self.target_update == 0:
self.target_q_net.load_state_dict(
self.q_net.state_dict()) # 更新目标网络
self.count += 1
def max_q_value(self, state):
state = torch.tensor([state], dtype=torch.float).to(self.device)
return self.q_net(state).max().item()
rl_utils.py
from tqdm import tqdm
import numpy as np
import torch
import collections
import random
class ReplayBuffer:
def __init__(self, capacity):
self.buffer = collections.deque(maxlen=capacity)
def add(self, state, action, reward, next_state, done):
self.buffer.append((state, action, reward, next_state, done))
def sample(self, batch_size):
transitions = random.sample(self.buffer, batch_size)
state, action, reward, next_state, done = zip(*transitions)
return np.array(state), action, reward, np.array(next_state), done
def size(self):
return len(self.buffer)
def moving_average(a, window_size):
cumulative_sum = np.cumsum(np.insert(a, 0, 0))
middle = (cumulative_sum[window_size:] - cumulative_sum[:-window_size]) / window_size
r = np.arange(1, window_size - 1, 2)
begin = np.cumsum(a[:window_size - 1])[::2] / r
end = (np.cumsum(a[:-window_size:-1])[::2] / r)[::-1]
return np.concatenate((begin, middle, end))
def train_on_policy_agent(env, agent, num_episodes):
return_list = []
for i in range(10):
with tqdm(total=int(num_episodes / 10), desc='Iteration %d' % i) as pbar:
for i_episode in range(int(num_episodes / 10)):
episode_return = 0
transition_dict = {'states': [], 'actions': [], 'next_states': [], 'rewards': [], 'dones': []}
state = env.reset()
done = False
while not done:
action = agent.take_action(state)
next_state, reward, done, _ = env.step(action)
transition_dict['states'].append(state)
transition_dict['actions'].append(action)
transition_dict['next_states'].append(next_state)
transition_dict['rewards'].append(reward)
transition_dict['dones'].append(done)
state = next_state
episode_return += reward
return_list.append(episode_return)
agent.update(transition_dict)
if (i_episode + 1) % 10 == 0:
pbar.set_postfix({'episode': '%d' % (num_episodes / 10 * i + i_episode + 1),
'return': '%.3f' % np.mean(return_list[-10:])})
pbar.update(1)
return return_list
def train_off_policy_agent(env, agent, num_episodes, replay_buffer, minimal_size, batch_size):
return_list = []
for i in range(10):
with tqdm(total=int(num_episodes / 10), desc='Iteration %d' % i) as pbar:
for i_episode in range(int(num_episodes / 10)):
episode_return = 0
state = env.reset()
done = False
while not done:
action = agent.take_action(state)
next_state, reward, done, _ = env.step(action)
replay_buffer.add(state, action, reward, next_state, done)
state = next_state
episode_return += reward
if replay_buffer.size() > minimal_size:
b_s, b_a, b_r, b_ns, b_d = replay_buffer.sample(batch_size)
transition_dict = {'states': b_s, 'actions': b_a, 'next_states': b_ns, 'rewards': b_r,
'dones': b_d}
agent.update(transition_dict)
return_list.append(episode_return)
if (i_episode + 1) % 10 == 0:
pbar.set_postfix({'episode': '%d' % (num_episodes / 10 * i + i_episode + 1),
'return': '%.3f' % np.mean(return_list[-10:])})
pbar.update(1)
return return_list
def compute_advantage(gamma, lmbda, td_delta):
td_delta = td_delta.detach().numpy()
advantage_list = []
advantage = 0.0
for delta in td_delta[::-1]:
advantage = gamma * lmbda * advantage + delta
advantage_list.append(advantage)
advantage_list.reverse()
return torch.tensor(advantage_list, dtype=torch.float)
标签：dim,return,Double,模型,list,state,action,DQN,self From： https://www.cnblogs.com/my-love-is-python/p/16656223.html