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Reinforced Imitation in Heterogeneous Action Space (arxiv.org)
3 points by sel1 on Aug 27, 2019 | hide | past | pdf | discuss on HN

In plain words: An agent learns from an expert whose actions it cannot copy, seeing only the expert's states and a rare reward, by slowly shifting from matching states to chasing the reward. In navigation tests it beat standard state-only copying and could even outperform the expert.

Abstract

Imitation learning is an effective alternative approach to learn a policy when the reward function is sparse. In this paper, we consider a challenging setting where an agent and an expert use different actions from each other. We assume that the agent has access to a sparse reward function and state-only expert observations. We propose a method which gradually balances between the imitation learning cost and the reinforcement learning objective. In addition, this method adapts the agent's policy based on either mimicking expert behavior or maximizing sparse reward. We show, through navigation scenarios, that (i) an agent is able to efficiently leverage sparse rewards to outperform standard state-only imitation learning, (ii) it can learn a policy even when its actions are different from the expert, and (iii) the performance of the agent is not bounded by that of the expert, due to the optimized usage of sparse rewards.

Konrad Zolna, Negar Rostamzadeh, Yoshua Bengio, Sungjin Ahn, Pedro O. Pinheiro
arXiv:1904.03438 · cs.LG, cs.AI, stat.ML · submitted Apr 6, 2019 · updated Aug 26, 2019
abstract · pdf · html · The extended version of the work "Reinforced Imitation Learning from Observations" presented on the NeurIPS workshop "Imitation Learning and its Challenges in Robotics"

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