in gym_wikinav/envs/wikinav_env/environment.py [0:0]
def _reward(self, idx):
if idx == self.graph.stop_sentinel:
if self.navigator.on_target or self.navigator.done:
# Return goal reward when first stopping on target and also at
# every subsequent timestep.
return self.goal_reward
else:
# Penalize for stopping on wrong page.
return -self.goal_reward
next_page = self.navigator.get_article_for_action(idx)
overlap = self.graph.get_relative_word_overlap(next_page,
self.navigator.target_id)
return overlap * self.goal_reward