Update DQN Atari Space Invaders.ipynb

Author: simoninithomas

DQN/Space Invaders/DQN Atari Space Invaders.ipynb

@@ -767,9 +767,9 @@
     "                target_Qs_batch = []\n",
     "\n",
     "                # Get Q values for next_state \n",
-    "                target_Qs = sess.run(DQNetwork.output, feed_dict = {DQNetwork.inputs_: next_states_mb})\n",
+    "                Qs_next_state = sess.run(DQNetwork.output, feed_dict = {DQNetwork.inputs_: next_states_mb})\n",
     "                \n",
-    "                # Set Qhat = r if the episode ends at s+1, otherwise set Qhat = r + gamma*maxQ(s', a')\n",
+    "                # Set Q_target = r if the episode ends at s+1, otherwise set Qhat = r + gamma*maxQ(s', a')\n",
     "                for i in range(0, len(batch)):\n",
     "                    terminal = dones_mb[i]\n",
     "\n",
@@ -778,7 +778,7 @@
     "                        target_Qs_batch.append(rewards_mb[i])\n",
     "                        \n",
     "                    else:\n",
-    "                        target = rewards_mb[i] + gamma * np.max(target_Qs[i])\n",
+    "                        target = rewards_mb[i] + gamma * np.max(Qs_next_state[i])\n",
     "                        target_Qs_batch.append(target)\n",
     "                        \n",
     "\n",