Paper:
Fast deep reinforcement learning using online adjustments from the past
We propose Ephemeral Value Adjusments (EVA): a means of allowing deep reinforcement learning agents to rapidly adapt to experience in their replay buffer. EVA shifts the value predicted by a neural network with an estimate of the value function found by planning over experience tuples from the replay buffer near the current state. EVA combines a number of recent ideas around combining episodic memory-like structures into reinforcement learning agents: slot-based storage, content-based retrieval, and memory-based planning. We show that EVA is performant on a demonstration task and Atari games.

Review:
Summary: This paper proposes a method that can help an RL agent to rapidly adapt to experience in the replay buffer. The method is the combination of slow and general component (i.e. model-free ) and episodic memories which are fast and adaptive. An interesting part of this proposed approach is that it slightly changes the replay buffer by adding trajectory information but get a good boost in the perfoamnce.  In addition, the extensive number of experiments have been conducted in order to verify the claim of this paper.   Comments and Questions - This paper, in general, is well-written (especially the related works, they actually talk about the relation and difference with previous works) except for the followings:     --  Section 3.1 and 3.2 do not have smooth flow. The message of these parts wasn't clear to me at first. it took me multiple iterations to find out what are the main take away from these parts. - Some variable or concepts are used without prior definition, the paper should be self-contained:  'e' in figure 1. Is it the same as 'e' in Algorithm 1? if yes, why different formats are used? if not, define.  Is it a scalar? vector?  - Define the counter-factual action. Again the paper should self-contained. - Line 62: 'The adjustment to the value function is not stored after it is... 'is very confusing to me.  Can you clarify? - Line 104-108: 'Since trajectory information is also stored, the 50 subsequent steps are also retrieved for each neighbour.' I am not sure understood this one, can you explain?  - Why in algorithm 1, 'h_t' is appended to the replay buffer but it is not sth that was mentioned in the text, eqautions, or figure. Can you explain?  In general, I like the idea of this paper and I wish the text was more clear (refer to above comments) Minor: -Line 123: 'W Idealy' is a typo? - In Algorithm 1: ' ...via the TCP algorithm', referring to the TCP equation(s) would be a better idea