  The navigation problem is classically approached in two steps: an exploration
step, where map-information about the environment is gathered; and an
exploitation step, where this information is used to navigate efficiently. Deep
reinforcement learning (DRL) algorithms, alternatively, approach the problem of
navigation in an end-to-end fashion. Inspired by the classical approach, we ask
whether DRL algorithms are able to inherently explore, gather and exploit
map-information over the course of navigation. We build upon Mirowski et al.
[2017] work and introduce a systematic suite of experiments that vary three
parameters: the agent's starting location, the agent's target location, and the
maze structure. We choose evaluation metrics that explicitly measure the
algorithm's ability to gather and exploit map-information. Our experiments show
that when trained and tested on the same maps, the algorithm successfully
gathers and exploits map-information. However, when trained and tested on
different sets of maps, the algorithm fails to transfer the ability to gather
and exploit map-information to unseen maps. Furthermore, we find that when the
goal location is randomized and the map is kept static, the algorithm is able
to gather and exploit map-information but the exploitation is far from optimal.
We open-source our experimental suite in the hopes that it serves as a
framework for the comparison of future algorithms and leads to the discovery of
robust alternatives to classical navigation methods.
