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add dqn

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JohnJim0816
2020-09-08 13:36:26 +08:00
parent f0d19ac14f
commit 106cfcc714
10 changed files with 108 additions and 83 deletions
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codes/dqn/dqn.py
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@@ -5,12 +5,16 @@
@Email: johnjim0816@gmail.com
@Date: 2020-06-12 00:50:49
@LastEditor: John
@LastEditTime: 2020-06-14 13:56:45
LastEditTime: 2020-08-22 15:44:31
@Discription:
@Environment: python 3.7.7
'''
'''off-policy
'''
import torch
import torch.nn as nn
import torch.optim as optim
@@ -20,79 +24,97 @@ import math
import numpy as np
from memory import ReplayBuffer
from model import FCN
class DQN:
def __init__(self, n_states, n_actions, gamma=0.99, epsilon_start=0.9, epsilon_end=0.05, epsilon_decay=200, memory_capacity=10000, policy_lr=0.01,batch_size=128, device="cpu"):
def __init__(self, n_states, n_actions, gamma=0.99, epsilon_start=0.9, epsilon_end=0.05, epsilon_decay=200, memory_capacity=10000, policy_lr=0.01, batch_size=128, device="cpu"):
self.actions_count = 0
self.n_actions = n_actions
self.device = device
self.n_actions = n_actions # 总的动作个数
self.device = device # 设备，cpu或gpu等
self.gamma = gamma
# e-greedy策略相关参数
self.epsilon = 0
self.epsilon_start = epsilon_start
self.epsilon_end = epsilon_end
self.epsilon_decay = epsilon_decay
self.batch_size = batch_size
self.policy_net = FCN(n_states,n_actions).to(self.device)
self.target_net = FCN(n_states,n_actions).to(self.device)
self.policy_net = FCN(n_states, n_actions).to(self.device)
self.target_net = FCN(n_states, n_actions).to(self.device)
# target_net的初始模型参数完全复制policy_net
self.target_net.load_state_dict(self.policy_net.state_dict())
self.target_net.eval() # 不启用 BatchNormalization 和 Dropout
self.optimizer = optim.Adam(self.policy_net.parameters(),lr=policy_lr)
# 可查parameters()与state_dict()的区别，前者require_grad=True
self.optimizer = optim.Adam(self.policy_net.parameters(), lr=policy_lr)
self.loss = 0
self.memory = ReplayBuffer(memory_capacity)
def select_action(self,state):
'''选择工作
def select_action(self, state):
'''选择动作
Args:
state [array]: 状态
state [array]: [description]
Returns:
[array]: 动作
action [array]: [description]
'''
self.epsilon = self.epsilon_end + (self.epsilon_start - self.epsilon_end) * \
math.exp(-1. * self.actions_count / self.epsilon_decay)
self.actions_count += 1
if random.random() > self.epsilon:
with torch.no_grad():
state = torch.tensor([state],device=self.device,dtype=torch.float32) # 先转为张量便于丢给神经网络,state元素数据原本为float64；注意state=torch.tensor(state).unsqueeze(0)跟state=torch.tensor([state])等价
q_value = self.policy_net(state) # tensor([[-0.0798, -0.0079]], grad_fn=<AddmmBackward>)
action = q_value.max(1)[1].item()
# 先转为张量便于丢给神经网络,state元素数据原本为float64
# 注意state=torch.tensor(state).unsqueeze(0)跟state=torch.tensor([state])等价
state = torch.tensor(
[state], device=self.device, dtype=torch.float32)
# 如tensor([[-0.0798, -0.0079]], grad_fn=<AddmmBackward>)
q_value = self.policy_net(state)
# tensor.max(1)返回每行的最大值以及对应的下标，
# 如torch.return_types.max(values=tensor([10.3587]),indices=tensor([0]))
# 所以tensor.max(1)[1]返回最大值对应的下标，即action
action = q_value.max(1)[1].item()
else:
action = random.randrange(self.n_actions)
return action
def update(self):
if len(self.memory) < self.batch_size:
return
# 从memory中随机采样transition
state_batch, action_batch, reward_batch, next_state_batch, done_batch = self.memory.sample(
self.batch_size)
# 转为张量
# 例如tensor([[-4.5543e-02, -2.3910e-01, 1.8344e-02, 2.3158e-01],...,[-1.8615e-02, -2.3921e-01, -1.1791e-02, 2.3400e-01]])
state_batch = torch.tensor(
state_batch, device=self.device, dtype=torch.float)
action_batch = torch.tensor(action_batch, device=self.device).unsqueeze(
1) # 例如tensor([[1],...,[0]])
reward_batch = torch.tensor(
reward_batch, device=self.device, dtype=torch.float) # tensor([1., 1.,...,1])
next_state_batch = torch.tensor(
next_state_batch, device=self.device, dtype=torch.float)
done_batch = torch.tensor(np.float32(
done_batch), device=self.device).unsqueeze(1) # 将bool转为float然后转为张量
state_batch, action_batch, reward_batch, next_state_batch, done_batch = self.memory.sample(self.batch_size)
state_batch = torch.tensor(state_batch,device=self.device,dtype=torch.float) # 例如tensor([[-4.5543e-02, -2.3910e-01, 1.8344e-02, 2.3158e-01],...,[-1.8615e-02, -2.3921e-01, -1.1791e-02, 2.3400e-01]])
action_batch = torch.tensor(action_batch,device=self.device).unsqueeze(1) # 例如tensor([[1],...,[0]])
reward_batch = torch.tensor(reward_batch,device=self.device,dtype=torch.float) # tensor([1., 1.,...,1])
next_state_batch = torch.tensor(next_state_batch,device=self.device,dtype=torch.float)
done_batch = torch.tensor(np.float32(done_batch),device=self.device).unsqueeze(1) # 将bool转为float然后转为张量
# Compute Q(s_t, a) - the model computes Q(s_t), then we select the
# columns of actions taken. These are the actions which would've been taken
# for each batch state according to policy_net
q_values = self.policy_net(state_batch).gather(1, action_batch) # 等价于self.forward
# Compute V(s_{t+1}) for all next states.
# Expected values of actions for non_final_next_states are computed based
# on the "older" target_net; selecting their best reward with max(1)[0].
# This is merged based on the mask, such that we'll have either the expected
# state value or 0 in case the state was final.
# 计算当前(s_t,a)对应的Q(s_t, a)
# 关于torch.gather,对于a=torch.Tensor([[1,2],[3,4]])
# 那么a.gather(1,torch.Tensor([[0],[1]]))=torch.Tensor([[1],[3]])
q_values = self.policy_net(state_batch).gather(
dim=1, index=action_batch) # 等价于self.forward
# 计算所有next states的V(s_{t+1})，即通过target_net中选取reward最大的对应states
next_state_values = self.target_net(
next_state_batch).max(1)[0].detach() # tensor([ 0.0060, -0.0171,...,])
# Compute the expected Q values
expected_q_values = reward_batch + self.gamma * next_state_values * (1-done_batch[0])
# Compute Huber loss
# self.loss = nn.MSELoss(q_values, expected_q_values.unsqueeze(1))
self.loss = nn.MSELoss()(q_values,expected_q_values.unsqueeze(1))
# Optimize the model
self.optimizer.zero_grad() # zero_grad clears old gradients from the last step (otherwise you’d just accumulate the gradients from all loss.backward() calls).
self.loss.backward() # loss.backward() computes the derivative of the loss w.r.t. the parameters (or anything requiring gradients) using backpropagation.
for param in self.policy_net.parameters(): # clip防止梯度爆炸
next_state_batch).max(1)[0].detach() # 比如tensor([ 0.0060, -0.0171,...,])
# 计算 expected_q_value
# 对于终止状态，此时done_batch[0]=1, 对应的expected_q_value等于reward
expected_q_values = reward_batch + self.gamma * \
next_state_values * (1-done_batch[0])
# self.loss = F.smooth_l1_loss(q_values,expected_q_values.unsqueeze(1)) # 计算 Huber loss
self.loss = nn.MSELoss()(q_values, expected_q_values.unsqueeze(1)) # 计算 均方误差loss
# 优化模型
self.optimizer.zero_grad() # zero_grad清除上一步所有旧的gradients from the last step
# loss.backward()使用backpropagation计算loss相对于所有parameters(需要gradients)的微分
self.loss.backward()
for param in self.policy_net.parameters(): # clip防止梯度爆炸
param.grad.data.clamp_(-1, 1)
self.optimizer.step() # causes the optimizer to take a step based on the gradients of the parameters.
self.optimizer.step() # 更新模型
def save_model():
pass
def load_model():
pass