强化学习入门 (Introduction to Reinforcement Learning)

强化学习基础 (Reinforcement Learning Basics)

强化学习是一种通过与环境交互来学习最优策略的机器学习方法,通过试错和奖励机制来实现目标。

Reinforcement Learning is a machine learning method that learns optimal policies through interaction with an environment, achieving goals through trial-and-error and reward mechanisms.

核心概念 (Core Concepts)

基本要素 (Basic Elements)

  • 状态空间 (State Space)
  • 动作空间 (Action Space)
  • 奖励函数 (Reward Function)
  • 策略函数 (Policy Function)

价值函数 (Value Functions)

  • 状态价值函数 (State Value Function)
  • 动作价值函数 (Action Value Function)
  • 优势函数 (Advantage Function)

探索与利用 (Exploration vs Exploitation)

  • ε-贪心策略 (ε-greedy Policy)
  • 玻尔兹曼探索 (Boltzmann Exploration)
  • 参数噪声 (Parameter Noise)

经典算法 (Classic Algorithms)

基于价值的方法 (Value-based Methods)

  • Q-Learning
  • DQN (Deep Q-Network)
  • Double DQN

基于策略的方法 (Policy-based Methods)

  • REINFORCE
  • Actor-Critic
  • PPO (Proximal Policy Optimization)

实践应用 (Practical Applications)

游戏AI (Game AI)

import gym
import numpy as np

# 创建环境 (Create environment)
env = gym.make('CartPole-v1')

# Q-learning实现 (Q-learning implementation)
class QLearningAgent:
    def __init__(self, state_size, action_size):
        self.q_table = np.zeros((state_size, action_size))
        self.learning_rate = 0.1
        self.gamma = 0.95
        self.epsilon = 0.1
    
    def choose_action(self, state):
        if np.random.random() < self.epsilon:
            return env.action_space.sample()
        return np.argmax(self.q_table[state])
    
    def learn(self, state, action, reward, next_state):
        old_value = self.q_table[state, action]
        next_max = np.max(self.q_table[next_state])
        new_value = (1 - self.learning_rate) * old_value + \
                   self.learning_rate * (reward + self.gamma * next_max)
        self.q_table[state, action] = new_value

机器人控制 (Robot Control)

  • 运动规划 (Motion Planning)
  • 任务学习 (Task Learning)
  • 多智能体系统 (Multi-agent Systems)

推荐系统 (Recommendation Systems)

  • 用户交互 (User Interaction)
  • 个性化推荐 (Personalized Recommendations)
  • 在线学习 (Online Learning)

高级主题 (Advanced Topics)

分层强化学习 (Hierarchical RL)

  • 选项框架 (Options Framework)
  • 目标分解 (Goal Decomposition)
  • 技能迁移 (Skill Transfer)

多任务学习 (Multi-task Learning)

  • 任务表示 (Task Representation)
  • 知识迁移 (Knowledge Transfer)
  • 课程学习 (Curriculum Learning)

实战项目 (Hands-on Project)

在下一节中,我们将实现一个强化学习智能体来玩简单的游戏,理解基本的强化学习概念和实现方法。

In the next section, we will implement a reinforcement learning agent to play simple games, understanding basic RL concepts and implementation methods.