adding slides for cross entropy RL method

Author: eclarson

08a_Basics_of_Reinforcement_Learning.ipynb

@@ -71,7 +71,10 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "https://github.com/PacktPublishing/Deep-Reinforcement-Learning-Hands-On/blob/master/Chapter04/01_cartpole.py"
+    "We will start with an example that we manipualted from the following book by M. Lapan: \n",
+    "https://github.com/PacktPublishing/Deep-Reinforcement-Learning-Hands-On/blob/master/Chapter04/01_cartpole.py\n",
+    "\n",
+    "This is a nice introduction to RL with many pytorch examples included, similar to the one below. Here I have manipulated the example to run in jupyter, changed a few default behaviors, and added many more comments for understanding. "
    ]
   },
   {
@@ -194,8 +197,8 @@
     "        if example.reward >= reward_bound:\n",
     "            # extend data arrays with obs and desired actions\n",
     "            # extend adds elements to list from another list\n",
-    "            # Syntax: map(function, what to iterate over)\n",
-    "            # just get the actions and observations for this episode\n",
+    "            #   Syntax: map(function, what to iterate over)\n",
+    "            #   just get the actions and observations for this episode\n",
     "            train_obs.extend(map(lambda step: step.observation, example.steps))\n",
     "            train_act.extend(map(lambda step: step.action, example.steps))\n",
     "\n",
@@ -340,7 +343,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "env.close()# calling this will end the current environment"
+    "env.close()# calling this will close and delete the current environment"
    ]
   },
   {