AdvancedTopic 100 of 104Software & Computing
Reinforcement learning
Agents learn by trial and reward.
In depth
An agent learns a policy by interacting with an environment and receiving rewards, balancing exploration and exploitation. Methods: Q-learning, policy gradients, actor-critic, PPO. Applications: games (AlphaGo), robotics, resource management, RLHF. Sample efficiency and safe exploration are challenges.
Key points
- Markov decision process
- Discount factor
- Reward design
ExampleA robot learns to walk by trial and error in simulation.
What is Reinforcement learning?
Agents learn by trial and reward.
Why is it important to understand reinforcement learning?
Reinforcement learning trains agents by reward, so it suits control problems where the best behaviour must be discovered by trial.
What is a reward signal?
A number the environment gives to the agent after an action, which the agent tries to maximise over time.
Why is reinforcement learning hard in practice?
It needs many trials, which can be unsafe or expensive in the real world, so simulation and careful reward design are important.
How is Reinforcement learning used in practice?
Typical applications include training a robot to walk by rewarding forward progress, optimising the control of a process plant through simulation and learning a strategy for scheduling energy storage under changing prices.
What should I learn before Reinforcement learning?
Study "Computer vision" first (topic 99 of 104 in Software & Computing). It covers the groundwork this topic builds on.
What are the key points of Reinforcement learning?
Markov decision process. Discount factor. Reward design.
Can you give an example of Reinforcement learning?
A robot learns to walk by trial and error in simulation.
What comes after Reinforcement learning?
The next topic is "MLOps and ethics", which builds directly on this one.
How difficult is Reinforcement learning?
It is classed as Advanced in Software & Computing (topic 100 of 104). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Software & Computing.