Discussing the article: "Neural networks made easy (Part 51): Behavior-Guided Actor-Critic (BAC)"


Check out the new article: Neural networks made easy (Part 51): Behavior-Guided Actor-Critic (BAC).

The last two articles considered the Soft Actor-Critic algorithm, which incorporates entropy regularization into the reward function. This approach balances environmental exploration and model exploitation, but it is only applicable to stochastic models. The current article proposes an alternative approach that is applicable to both stochastic and deterministic models.

First, let's talk about the need to study the environment in general. I think everyone agrees that this process is necessary. But for what exactly and at what stage?

Let's start with a simple example. Suppose that we find ourselves in a room with three identical doors and we need to get into the street. What shall we do? We open the doors one by one until we find the one we need. When we enter the same room again, we will no longer open all the doors to get outside, but instead we will immediately head to the already known exit. If we have a different task, then some options are possible. We can again open all the doors, except for the exit we already know, and look for the right one. Or we can first remember which doors we opened earlier when looking for a way out and whether the one we need was among them. If we remember the right door, we head towards it. Otherwise, we check the doors we have not tried before.

Conclusion: We need to study the environment in an unfamiliar situation to choose the right action. After finding the required route, additional exploration of the environment can only get in the way.

However, when the task changes in a known state, we may need to additionally study the environment. This may include searching for a more optimal route. In the example above, this may happen if we needed to go through several more rooms or we found ourselves at the wrong side of the building.

Therefore, we need an algorithm that allows us to enhance environmental exploration in unexplored states and minimize it in previously explored states.

Author: Dmitriy Gizlyk