From fair solutions to compromise solutions in multi-objective deep reinforcement learning
摘要
In this paper, we focus on multi-objective reinforcement learning (RL) where the expected vector returns are aggregated with a concave function. For this generic framework, which includes notably fair optimization in the multi-user setting and compromise optimization in the multi-criteria setting, we present several contributions. After a discussion of its theoretical properties (e.g., need to resort to stochastic policies), we prove a general performance bound that justifies learning a policy using discounted rewards, even if a policy optimal for the average reward is desired. We extend several deep RL algorithms for our problem; notably our adaptation of DQN can learn stochastic policies. In addition, to illustrate the generality of our framework, we consider in the multi-user setting a novel extension of fair optimization in deep RL where users have different entitlements. Our experimental results validate our propositions and also demonstrate its superiority to reward engineering in single-objective RL.