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## Why is Q learning considered an off-policy control method?

Q-learning is called off-policy because the updated policy is different from the behavior policy, so Q-Learning is off-policy. In other words, it estimates the reward for future actions and appends a value to the new state without actually following any greedy policy.

**Is Deep Q learning off-policy?**

Q-learning is an off-policy algorithm (Sutton & Barto, 1998), meaning the target can be computed without consideration of how the experience was generated. In principle, off- policy reinforcement learning algorithms are able to learn from data collected by any behavioral policy.

**What is Q learning used for?**

Q-Learning is a value-based reinforcement learning algorithm which is used to find the optimal action-selection policy using a Q function. Our goal is to maximize the value function Q. The Q table helps us to find the best action for each state.

### Is Q learning on-policy or off policy?

Q-learning is an off-policy learner. An on-policy learner learns the value of the policy being carried out by the agent, including the exploration steps.

**Is Q learning on-policy or off-policy?**

**Is Q learning model based?**

Q-learning is a model-free reinforcement learning algorithm. Q-learning is a values-based learning algorithm. Means it learns the value of the optimal policy independently of the agent’s actions.

#### What is Q-value in Q learning?

Q-Learning is a basic form of Reinforcement Learning which uses Q-values (also called action values) to iteratively improve the behavior of the learning agent. Q-Values or Action-Values: Q-values are defined for states and actions. is an estimation of how good is it to take the action at the state .

**Is Q-learning a policy gradient method?**

Deep-Q-learning is a value based method while Policy Gradient is a policy based method. It can learn the stochastic policy ( outputs the probabilities for every action ) which is useful for handling the exploration/exploitation trade off.

**What is the relation between Q-learning and policy gradients methods?**

Thus, policy gradient methods are on-policy methods. Q-Learning only makes sure to satisfy the Bellman-Equation. This equation has to hold true for all transitions. Therefore, Q-learning can also use experiences collected from previous policies and is off-policy.

## What’s the difference between model-based and Q-learning?

Whereas, a model-based algorithm is an algorithm that uses the transition function (and the reward function) in order to estimate the optimal policy. Q-learning is a model-free reinforcement learning algorithm. Q-learning is a values-based learning algorithm.

**What do you need to know about Q-learning?**

Q* (s,a) is the expected value (cumulative discounted reward) of doing a in state s and then following the optimal policy. Q-learning uses Temporal Differences (TD) to estimate the value of Q* (s,a). Temporal difference is an agent learning from an environment through episodes with no prior knowledge of the environment.

**How is Q-learning different from other learning algorithms?**

Q-learning is a values-based learning algorithm. Value based algorithms updates the value function based on an equation (particularly Bellman equation). Whereas the other type, policy-based estimates the value function with a greedy policy obtained from the last policy improvement. Q-learning is an off-policy learner.