add some codes

codes/ddpg/model.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+# coding=utf-8
+'''
+@Author: John
+@Email: johnjim0816@gmail.com
+@Date: 2020-06-10 15:03:59
+@LastEditor: John
+@LastEditTime: 2020-06-14 11:42:45
+@Discription: 
+@Environment: python 3.7.7
+'''
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+class Critic(nn.Module):
+    def __init__(self, n_obs, n_actions, hidden_size, init_w=3e-3):
+        super(Critic, self).__init__()
+        
+        self.linear1 = nn.Linear(n_obs + n_actions, hidden_size)
+        self.linear2 = nn.Linear(hidden_size, hidden_size)
+        self.linear3 = nn.Linear(hidden_size, 1)
+    
+        self.linear3.weight.data.uniform_(-init_w, init_w)
+        self.linear3.bias.data.uniform_(-init_w, init_w)
+        
+    def forward(self, state, action):
+        x = torch.cat([state, action], 1)
+        x = F.relu(self.linear1(x))
+        x = F.relu(self.linear2(x))
+        x = self.linear3(x)
+        return x
+
+class Actor(nn.Module):
+    def __init__(self, n_obs, n_actions, hidden_size, init_w=3e-3):
+        super(Actor, self).__init__()  
+        self.linear1 = nn.Linear(n_obs, hidden_size)
+        self.linear2 = nn.Linear(hidden_size, hidden_size)
+        self.linear3 = nn.Linear(hidden_size, n_actions)
+        
+        self.linear3.weight.data.uniform_(-init_w, init_w)
+        self.linear3.bias.data.uniform_(-init_w, init_w)
+        
+    def forward(self, x):
+        x = F.relu(self.linear1(x))
+        x = F.relu(self.linear2(x))
+        x = F.tanh(self.linear3(x))
+        return x
+    
+    def select_action(self, state):
+        
+        device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+        state  = torch.FloatTensor(state).unsqueeze(0).to(device)
+        # print(state)
+        action = self.forward(state)
+        return action.detach().cpu().numpy()[0, 0]