diff --git a/agents/async_dqn_agent.py b/agents/async_dqn_agent.py
index e24110e..6b50f4c 100644
--- a/agents/async_dqn_agent.py
+++ b/agents/async_dqn_agent.py
@@ -12,14 +12,29 @@ def __init__(self, input_channel: int, action_dim: int, learning_rate: float,
 
 
 class AsyncDQNAgent(DQNAgent):
-    def __init__(self,input_frame_width: int, input_frame_height: int, action_space,
-                 mini_batch_size: int, replay_buffer_size: int, learning_rate: float, step_c: int, model_saving_period: int,
+    def __init__(self, input_frame_width: int, input_frame_height: int, action_space,
+                 mini_batch_size: int, replay_buffer_size: int, learning_rate: float, step_c: int,
+                 model_saving_period: int,
                  gamma: float, training_episodes: int, phi_channel: int, epsilon_max: float, epsilon_min: float,
                  exploration_steps: int, device: torch.device, logger: Logger):
         super(AsyncDQNAgent, self).__init__(input_frame_width, input_frame_height, action_space,
-                                            mini_batch_size, replay_buffer_size, mini_batch_size+1,
+                                            mini_batch_size, replay_buffer_size, mini_batch_size + 1,
                                             learning_rate, step_c, model_saving_period,
                                             gamma, training_episodes, phi_channel, epsilon_max, epsilon_min,
                                             exploration_steps, device, logger)
 
-
+    def train_step(self, rank: int = 0):
+        """
+        Perform a training step if the memory size is larger than the update sample size.
+        """
+        if len(self.memory) > self.replay_start_size:
+            samples, w, idx = self.memory.sample(self.mini_batch_size)
+            loss, q = self.value_function.update(samples, w).reshape(1, -1) + np.float32(1e-5)
+            self.memory.p[idx] = loss
+            self.update_step += 1
+            # synchronize the target value neural network with the value neural network every step_c steps
+            if self.update_step % self.step_c == 0 and rank == 0:
+                self.value_function.synchronize_value_nn()
+                if self.logger:
+                    self.logger.tb_scalar('loss', np.mean(loss), self.update_step)
+                    self.logger.tb_scalar('q', torch.mean(q), self.update_step)
diff --git a/agents/dqn_agent.py b/agents/dqn_agent.py
index 0ddf124..fe2c00d 100644
--- a/agents/dqn_agent.py
+++ b/agents/dqn_agent.py
@@ -128,7 +128,7 @@ def __call__(self, state: np.ndarray, step_i: int) -> np.ndarray:
 class DQNValueFunction(ValueFunction):
 
     def __init__(self, input_channel: int, action_dim: int, learning_rate: float,
-                 gamma: float, step_c: int, model_saving_period: int, device: torch.device, logger: Logger):
+                 gamma: float,  model_saving_period: int, device: torch.device, logger: Logger,):
         super(DQNValueFunction, self).__init__()
         self.logger = logger
         # Define the value neural network and the target value neural network
@@ -142,12 +142,10 @@ def __init__(self, input_channel: int, action_dim: int, learning_rate: float,
         self.gamma = gamma
         self.device = device
         self.update_step = 0
-        self.step_c = step_c
         self.model_saving_period = model_saving_period
 
     # synchronize the target value neural network with the value neural network
     def synchronize_value_nn(self):
-
         self.target_value_nn.load_state_dict(self.value_nn.state_dict())
 
     def max_state_value(self, obs_tensor):
@@ -190,7 +188,6 @@ def update(self, samples: list, weight=None):
         obs_tensor = image_normalization(obs_tensor)
         outputs = self.value_nn(obs_tensor)
         obs_action_value = outputs.gather(1, actions)
-
         # Clip the difference between obs_action_value and q_value to the range of -1 to 1
         # in [prioritized experience replay]() algorithm, weight is used to adjust the importance of the samples
         diff = obs_action_value - q_value
@@ -204,13 +201,8 @@ def update(self, samples: list, weight=None):
         loss.backward()
         self.optimizer.step()
         self.update_step += 1
-        # synchronize the target value neural network with the value neural network every step_c steps
-        if self.update_step % self.step_c == 0:
-            self.synchronize_value_nn()
-            if self.logger:
-                self.logger.tb_scalar('loss', loss.item(), self.update_step)
-                self.logger.tb_scalar('q', torch.mean(q_value), self.update_step)
-        return np.abs(diff_clipped.detach().cpu().numpy().astype(np.float32))
+        return (np.abs(diff_clipped.detach().cpu().numpy().astype(np.float32)),
+                q_value.detach().cpu().numpy().astype(np.float32))
 
     # Calculate the value of the given phi tensor.
     def value(self, phi_tensor: torch.Tensor) -> np.ndarray:
@@ -253,6 +245,8 @@ def __init__(self, input_frame_width: int, input_frame_height: int, action_space
         self.mini_batch_size = mini_batch_size
         self.replay_start_size = replay_start_size
         self.training_episodes = training_episodes
+        self.update_step = 0
+        self.step_c = step_c
 
     # Select an action based on the given observation and exploration method.
     def select_action(self, obs: np.ndarray, exploration_method: Exploration = None) -> np.ndarray:
@@ -295,4 +289,12 @@ def train_step(self):
 
         if len(self.memory) > self.replay_start_size:
             samples = self.memory.sample(self.mini_batch_size)
-            self.value_function.update(samples)
+            loss, q = self.value_function.update(samples)
+            self.update_step += 1
+            # synchronize the target value neural network with the value neural network every step_c steps
+            if self.update_step % self.step_c == 0:
+                self.value_function.synchronize_value_nn()
+                if self.logger:
+                    self.logger.tb_scalar('loss', np.mean(loss), self.update_step)
+                    self.logger.tb_scalar('q', torch.mean(q), self.update_step)
+
diff --git a/agents/dqn_pp_agent.py b/agents/dqn_pp_agent.py
index ff616c3..380bc19 100644
--- a/agents/dqn_pp_agent.py
+++ b/agents/dqn_pp_agent.py
@@ -40,12 +40,18 @@ def __init__(self, input_frame_width: int, input_frame_height: int, action_space
         gc.collect()
         self.memory = ProportionalPrioritization(replay_buffer_size, alpha, beta)
 
-
     def train_step(self):
         """
         Perform a training step if the memory size is larger than the update sample size.
         """
         if len(self.memory) > self.replay_start_size:
             samples, w, idx = self.memory.sample(self.mini_batch_size)
-            td_err = self.value_function.update(samples, w).reshape(1, -1) + np.float32(1e-5)
-            self.memory.p[idx] = td_err
+            loss, q = self.value_function.update(samples, w).reshape(1, -1) + np.float32(1e-5)
+            self.memory.p[idx] = loss
+            self.update_step += 1
+            # synchronize the target value neural network with the value neural network every step_c steps
+            if self.update_step % self.step_c == 0:
+                self.value_function.synchronize_value_nn()
+                if self.logger:
+                    self.logger.tb_scalar('loss', np.mean(loss), self.update_step)
+                    self.logger.tb_scalar('q', torch.mean(q), self.update_step)
diff --git a/algorithms/async_dqn.py b/algorithms/async_dqn.py
index 559b56f..983a2a2 100644
--- a/algorithms/async_dqn.py
+++ b/algorithms/async_dqn.py
@@ -76,7 +76,7 @@ def train(rank: int, agent: AsyncDQNAgent, env: EnvWrapper,
             reward = agent.reward_shaping(reward_raw)
             next_obs = agent.perception_mapping(next_state, step_i)
             agent.store(obs, action, reward, next_obs, done, truncated)
-            agent.train_step()
+            agent.train_step(rank)
             obs = next_obs
             reward_cumulated += reward
             training_steps += 1