Deep reinforcement learning (RL) has achieved outstanding results in recent
years. This has led to a dramatic increase in the number of applications and
methods. Recent works have explored learning beyond single-agent scenarios and
have considered multiagent learning (MAL) scenarios. Initial results report
successes in complex multiagent domains, although there are several challenges
to be addressed. The primary goal of this article is to provide a clear
overview of current multiagent deep reinforcement learning (MDRL) literature.
Additionally, we complement the overview with a broader analysis: (i) we
revisit previous key components, originally presented in MAL and RL, and
highlight how they have been adapted to multiagent deep reinforcement learning
settings. (ii) We provide general guidelines to new practitioners in the area:
describing lessons learned from MDRL works, pointing to recent benchmarks, and
outlining open avenues of research. (iii) We take a more critical tone raising
practical challenges of MDRL (e.g., implementation and computational demands).
We expect this article will help unify and motivate future research to take
advantage of the abundant literature that exists (e.g., RL and MAL) in a joint
effort to promote fruitful research in the multiagent community.Comment: Under review since Oct 2018. Earlier versions of this work had the
title: "Is multiagent deep reinforcement learning the answer or the question?
A brief survey