# Deep Reinforcement Learning
### Intro from CS 285
RL is fundamentally two things:
1. A mathematical formalism for learning-based decision making (this allows us to design algorithms)
2. An approach for learning decision making and control **from experience**(rather than relying on policy being designed by hand)
How is this different from other ML topics?

In RL, we model a decision making system as an interaction between an agent and an environment. The **agent** makes **decisions (actions)** and the **environment** responds to those actions with **observations** (which we call **states**) and **rewards**. Crucially, this process is repeated multiple times.
The real world is unstructured and unpredictable. [Deep-Learning](Deep-Learning.md) helps us handle *unstructured environments*. In DL we train a very large, heavily over parameterized model to map inputs to outputs.
RL provides a formalism for *behavior*.
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Date: 20211124
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* [Great intro course, combined with DL](https://www.youtube.com/watch?v=JHrlF10v2Og&list=PL_iWQOsE6TfURIIhCrlt-wj9ByIVpbfGc)