So imagine you have a robot that needs to navigate through a maze to find the exit. The robot starts in one corner and can move left or right at each intersection. If it reaches the end of the maze, it gets rewarded with points (let’s say 100). But if it hits a wall or goes in circles, it loses points (-5 for every step taken).
Now policy-based methods. This means that instead of learning specific actions to take based on the current state (like “move left” or “turn right”), we teach the robot how to make decisions based on its overall strategy or policy. For example, if the robot always moves towards the center of the maze and avoids walls as much as possible, it will eventually learn to navigate through the maze more efficiently than if it just randomly chose left or right at each intersection.
So in this case, our “policy” would be something like: “move forward until you hit a wall, then turn left unless there’s another wall on that side, otherwise move straight ahead”. This policy can be represented as a set of rules or decision trees, which the robot uses to make decisions based on its current state and previous experiences.
Now reinforcement learning specifically. In this context, “reinforcement” means that we are rewarding the robot for taking certain actions (like moving towards the exit) and punishing it for taking others (like hitting a wall). This feedback helps the robot learn which actions are more likely to lead to a successful outcome in the future.
So how does this all work in practice? Well, first we need to define our environment (in this case, the maze), and then create a model that can represent different states within that environment. For example, one state might be “robot is at intersection with left wall”, while another might be “robot is at intersection with right wall”.
Next, we train our policy-based method using reinforcement learning algorithms like Q-learning or SARSA (State Action Reward State Action). These algorithms allow us to learn which actions are most likely to lead to a successful outcome in the future based on previous experiences.
Finally, once our robot has learned how to navigate through the maze efficiently, we can use it to solve more complex problems like finding the shortest path between two points or avoiding obstacles in real-time environments. And that’s basically how policy-based methods for reinforcement learning work!