Discovery of Options via Meta-Learned Subgoals
This work addresses the problem of improving learning efficiency in reinforcement learning for multi-task domains, though it is incremental as it builds on prior option discovery methods.
The paper tackles the challenge of discovering useful options (temporal abstractions) in multi-task reinforcement learning environments by introducing a meta-gradient approach with a manager-worker decomposition, resulting in the discovery of meaningful and diverse options that help agents learn faster in new tasks.
Temporal abstractions in the form of options have been shown to help reinforcement learning (RL) agents learn faster. However, despite prior work on this topic, the problem of discovering options through interaction with an environment remains a challenge. In this paper, we introduce a novel meta-gradient approach for discovering useful options in multi-task RL environments. Our approach is based on a manager-worker decomposition of the RL agent, in which a manager maximises rewards from the environment by learning a task-dependent policy over both a set of task-independent discovered-options and primitive actions. The option-reward and termination functions that define a subgoal for each option are parameterised as neural networks and trained via meta-gradients to maximise their usefulness. Empirical analysis on gridworld and DeepMind Lab tasks show that: (1) our approach can discover meaningful and diverse temporally-extended options in multi-task RL domains, (2) the discovered options are frequently used by the agent while learning to solve the training tasks, and (3) that the discovered options help a randomly initialised manager learn faster in completely new tasks.