Hindsight experience replay

We have seen how experience replay is used in DQN to avoid a correlated experience. Also, we learned that prioritized experience replay is an improvement to the vanilla experience replay as it prioritizes each experience with the TD error. Now we will look at a new technique called hindsight experience replay (HER), proposed by OpenAI researchers for dealing with sparse rewards. Do you remember how you learned to ride a bike? On your first try, you wouldn't have balanced the bike properly. You would have failed several times to balance correctly. But all those failures don't mean you didn't learn anything. The failures would have taught you how not to balance a bike. Even though you did not learn to ride the bike (goal), you learned a different goal, that is, you learned how not to balance a bike. This is how we humans learn, right? We...