Actor-critic multi-objective reinforcement learning for non-linear utility functions
 
Actor-critic multi-objective reinforcement learning for non-linear utility functions ■
 
Mathieu Reymond, Mathieu Reymond, Mathieu Reymond, Conor F. Hayes, Conor F. Hayes, Conor F. Hayes, Denis Steckelmacher, Denis Steckelmacher, Denis Steckelmacher, Diederik M. Roijers, Diederik M. Roijers, Diederik M. Roijers, Ann Nowe, Ann Nowe, Ann Nowe
 
Abstract ■

We propose a novel multi-objective reinforcement learning algorithm that successfully learns the optimal policy even for non-linear utility functions. Non-linear utility functions pose a challenge for SOTA approaches, both in terms of learning efficiency as well as the solution concept. A key insight is that, by proposing a critic that learns a multi-variate distribution over the returns, which is then combined with accumulated rewards, we can directly optimize on the utility function, even if it is non-linear. This allows us to vastly increase the range of problems that can be solved compared to those which can be handled by single-objective methods or multi-objective methods requiring linear utility functions, yet avoiding the need to learn the full Pareto front. We demonstrate our method on multiple multi-objective benchmarks, and show that it learns effectively where baseline approaches fail.