Reinforcement learning refers to a group of methods from artificial intelligence where an agent performs learning through trial and error. It differs from supervised learning, since reinforcement learning requires no explicit labels; instead, the agent interacts continuously with its environment. That is, the agent starts in a specific state and then performs an action, based on which it transitions to a new state and, depending on the outcome, receives a reward. Different strategies (e.g. Q-learning) have been proposed to maximize the overall reward, resulting in a so-called policy, which defines the best possible action in each state. Mathematically, this process can be formalized by a Markov decision process and it has been implemented by packages in R; however, there is currently no package available for reinforcement learning. As a remedy, this paper demonstrates how to perform reinforcement learning in R and, for this purpose, introduces the ReinforcementLearning package. The package provides a remarkably flexible framework and is easily applied to a wide range of different problems. We demonstrate its use by drawing upon common examples from the literature (e.g. finding optimal game strategies).
Before I explain what Q Learning is, I will quickly explain the basic principle of reinforcement learning. Reinforcement learning is a category of machine learning algorithms where the systems learn on their own by interacting with the environment. The idea is that a reward is provided to the agent if the action it takes is correct. Otherwise, some penalty is assigned to discourage the action. It is similar to how we train dogs to perform tricks, give it a snack for successfully doing a roll and rebuke it for dirtying your carpet.
This is the first in a series of articles on reinforcement learning and OpenAI Gym. Suppose you're playing a video game. You enter a room with two doors. Behind Door 1 are 100 gold coins, followed by a passageway. Behind Door 2 is 1 gold coin, followed by a second passageway going in a different direction.
Today we'll learn about Q-Learning. Q-Learning is a value-based Reinforcement Learning algorithm. This article is the second part of a free series of blog post about Deep Reinforcement Learning. See the first article here. In this article you'll learn: Let's say you're a knight and you need to save the princess trapped in the castle shown on the map above.
In classical programming, software instructions are explicitly made by programmers and nothing is learned from the data at all. In contrast, machine learning is a field of computer science which uses statistical methods to enable computers to learn and to extract knowledge from the data without being explicitly programmed. In this reinforcement learning tutorial, I'll show how we can use PyTorch to teach a reinforcement learning neural network how to play Flappy Bird. But first, we'll need to cover a number of building blocks. Machine learning algorithms can roughly be divided into two parts: Traditional learning algorithms and deep learning algorithms. Traditional learning algorithms usually have much fewer learnable parameters than deep learning algorithms and have much less learning capacity. Also, traditional learning algorithms are not able to do feature extraction: Artificial intelligence specialists need to figure out a good data representation which is then sent to the learning algorithm. Examples of traditional machine learning techniques include SVM, random forest, decision tree, and $k$-means, whereas the central algorithm in deep learning is the deep neural network.