Variational Option Discovery Algorithms
  We explore methods for option discovery based on variational inference and
make two algorithmic contributions. First: we highlight a tight connection
between variational option discovery methods and variational autoencoders, and
introduce Variational Autoencoding Learning of Options by Reinforcement
(VALOR), a new method derived from the connection. In VALOR, the policy encodes
contexts from a noise distribution into trajectories, and the decoder recovers
the contexts from the complete trajectories. Second: we propose a curriculum
learning approach where the number of contexts seen by the agent increases
whenever the agent's performance is strong enough (as measured by the decoder)
on the current set of contexts. We show that this simple trick stabilizes
training for VALOR and prior variational option discovery methods, allowing a
single agent to learn many more modes of behavior than it could with a fixed
context distribution. Finally, we investigate other topics related to
variational option discovery, including fundamental limitations of the general
approach and the applicability of learned options to downstream tasks.
