Policy

Policy in RL.

An agent makes a decision according to its policy. For humans, brain is our policy because it observes what environment we are in (in a swimming pool!) and what actions we will react accordingly (swim).

Warning

Incoming math!

Formally, policy \( \pi \) is a function that takes in the state \( s \), and outputs an action \( a \), which the agent takes and arrive at a new state \( s' \).

Are policies the same thing as agents?

Agents are different from policies. An agent acts according a policy, which can be shared between agents. For example, in a futuristic world, you can control clones of your body. You have multiple bodies, but only a single brain. In such a case, the brain is the policy, and the agents are your bodies.