feat: complete DQN

pacman.py

@@ -127,6 +127,8 @@ def main():
 
     action_dim = env.action_space.n
     state_dim = (args.num_envs, args.image_hw, args.image_hw)
+    print(action_dim)
+    print(state_dim)
     agent = DQN(state_dim=state_dim, action_dim=action_dim)
     
     # train

rl_algorithm.py

@@ -11,15 +11,35 @@ class PacmanActionCNN(nn.Module):
         super(PacmanActionCNN, self).__init__()
         # build your own CNN model
         "*** YOUR CODE HERE ***"
-        utils.raiseNotDefined()
         # this is just an example, you can modify this.
-        self.conv1 = nn.Conv2d(state_dim, 16, kernel_size=8, stride=4)
+        self.conv1 = nn.Conv2d(state_dim, 16, kernel_size=3, stride=1, padding='same')
+        self.conv2 = nn.Conv2d(16, 16, kernel_size=3, stride=1, padding='same')
+        self.conv3 = nn.Conv2d(16, 32, kernel_size=3, stride=1, padding='same')
+        self.conv4 = nn.Conv2d(32, 32, kernel_size=3, stride=1, padding='same')
+        self.fc1 = nn.Linear(in_features=3200, out_features=512)
+        self.fc2 = nn.Linear(in_features=512, out_features=64)
+        self.fc3 = nn.Linear(in_features=64, out_features=action_dim)
+
+        self.pooling = nn.MaxPool2d(kernel_size=2, stride=2)
+        self.relu = nn.ReLU()
+        self.flatten = nn.Flatten()
 
     def forward(self, x):
-        x = F.relu(self.conv1(x))
 
         "*** YOUR CODE HERE ***"
-        utils.raiseNotDefined()
+        x = self.relu(self.conv1(x))
+        x = self.relu(self.conv2(x))
+        x = self.pooling(x)
+        x = self.relu(self.conv3(x))
+        x = self.pooling(x)
+        x = self.relu(self.conv4(x))
+        x = self.pooling(x)
+
+        x = self.flatten(x)
+        
+        x = self.relu(self.fc1(x))
+        x = self.relu(self.fc2(x))
+        x = self.fc3(x)
         
         return x
 
@@ -109,53 +129,56 @@ class DQN:
             x = torch.from_numpy(x).float().unsqueeze(0).to(self.device)
             
             "*** YOUR CODE HERE ***"
-            utils.raiseNotDefined()
+            # utils.raiseNotDefined()
             # get q-values from network
-            q_value = YOUR_CODE_HERE
+            q_value = self.network(x).squeeze()
             # get action with maximum q-value
-            action = YOUR_CODE_HERE
+            action = q_value.argmax().cpu()
         
         return action
     
     def learn(self):
         "*** YOUR CODE HERE ***"
-        utils.raiseNotDefined()
         
         # sample a mini-batch from replay buffer
         state, action, reward, next_state, terminated = map(lambda x: x.to(self.device), self.buffer.sample(self.batch_size))
+        action = action.to(torch.int64)
+        terminated = terminated.bool()
         
         # get q-values from network
-        next_q = YOUR_CODE_HERE
+        pred_q = self.network(state).gather(1, action)
+        next_q = self.target_network(next_state)
         # td_target: if terminated, only reward, otherwise reward + gamma * max(next_q)
-        td_target = YOUR_CODE_HERE
+        td_target = torch.where(terminated, reward, reward + self.gamma * next_q.max())
         # compute loss with td_target and q-values
-        loss = YOUR_CODE_HERE
+        criterion = nn.MSELoss()
+        loss = criterion(pred_q, td_target)
         
         # initialize optimizer
-        "self.optimizer.YOUR_CODE_HERE"
+        self.optimizer.zero_grad()
         # backpropagation
-        YOUR_CODE_HERE
+        loss.backward()
         # update network
-        "self.optimizer.YOUR_CODE_HERE"
+        self.optimizer.step()
         
-        return {YOUR_CODE_HERE} # return dictionary for logging
+        return {'value_loss': loss.item()} # return dictionary for logging
     
     def process(self, transition):
         "*** YOUR CODE HERE ***"
-        utils.raiseNotDefined()
         
         result = {}
         self.total_steps += 1
         
         # update replay buffer
         "self.buffer.YOUR_CODE_HERE"
+        self.buffer.update(*transition)
 
         if self.total_steps > self.warmup_steps:
             result = self.learn()
             
         if self.total_steps % self.target_update_interval == 0:
             # update target networ
-            "self.target_network.YOUR_CODE_HERE"
+            self.target_network.load_state_dict(self.network.state_dict())
         
         self.epsilon -= self.epsilon_decay
         return result