  In model-based reinforcement learning, generative and temporal models of
environments can be leveraged to boost agent performance, either by tuning the
agent's representations during training or via use as part of an explicit
planning mechanism. However, their application in practice has been limited to
simplistic environments, due to the difficulty of training such models in
larger, potentially partially-observed and 3D environments. In this work we
introduce a novel action-conditioned generative model of such challenging
environments. The model features a non-parametric spatial memory system in
which we store learned, disentangled representations of the environment.
Low-dimensional spatial updates are computed using a state-space model that
makes use of knowledge on the prior dynamics of the moving agent, and
high-dimensional visual observations are modelled with a Variational
Auto-Encoder. The result is a scalable architecture capable of performing
coherent predictions over hundreds of time steps across a range of partially
observed 2D and 3D environments.
