Extra Gym API functionality
What we have discussed so far covers two-thirds of the Gym core API and the essential functions required to start writing agents. The rest of the API you can live without, but it will make your life easier and the code cleaner. So, let’s briefly cover the rest of the API.
Wrappers
Very frequently, you will want to extend the environment’s functionality in some generic way. For example, imagine an environment gives you some observations, but you want to accumulate them in some buffer and provide to the agent the N last observations. This is a common scenario for dynamic computer games, when one single frame is just not enough to get the full information about the game state. Another example is when you want to be able to crop or preprocess an image’s pixels to make it more convenient for the agent to digest, or if you want to normalize reward scores somehow. There are many such situations that have the same...
