55 lines
1.6 KiB
Python
55 lines
1.6 KiB
Python
#!/usr/bin/env python
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# coding=utf-8
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'''
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Author: JiangJi
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Email: johnjim0816@gmail.com
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Date: 2021-05-03 22:16:08
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LastEditor: JiangJi
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LastEditTime: 2021-05-03 22:23:48
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Discription:
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Environment:
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'''
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import torch.optim as optim
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import torch.nn as nn
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import torch.nn.functional as F
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from torch.distributions import Categorical
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class ActorCritic(nn.Module):
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''' A2C网络模型，包含一个Actor和Critic
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'''
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def __init__(self, input_dim, output_dim, hidden_dim):
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super(ActorCritic, self).__init__()
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self.critic = nn.Sequential(
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nn.Linear(input_dim, hidden_dim),
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nn.ReLU(),
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nn.Linear(hidden_dim, 1)
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)
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self.actor = nn.Sequential(
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nn.Linear(input_dim, hidden_dim),
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nn.ReLU(),
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nn.Linear(hidden_dim, output_dim),
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nn.Softmax(dim=1),
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)
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def forward(self, x):
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value = self.critic(x)
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probs = self.actor(x)
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dist = Categorical(probs)
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return dist, value
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class A2C:
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''' A2C算法
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'''
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def __init__(self,n_states,n_actions,cfg) -> None:
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self.gamma = cfg.gamma
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self.device = cfg.device
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self.model = ActorCritic(n_states, n_actions, cfg.hidden_size).to(self.device)
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self.optimizer = optim.Adam(self.model.parameters())
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def compute_returns(self,next_value, rewards, masks):
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R = next_value
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returns = []
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for step in reversed(range(len(rewards))):
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R = rewards[step] + self.gamma * R * masks[step]
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returns.insert(0, R)
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return returns |