Define environment and metrics
Specify the state and action spaces, episodic termination rules, reward signal and metrics such as average episodic return, regret and variance across seeds.
Compare on-policy and off-policy. Inspect stability and returns.
On-policy and off-policy methods differ in whether the data used for learning comes from the policy being improved. On-policy learners (for example SARSA or policy-gradient methods) evaluate or improve the policy that generated experience. Off-policy learners (for example Q-learning or importance-sampling-based evaluation) learn about a target policy from data collected by another behaviour policy. Typical error cases include non-stationary rewards, insufficient coverage of the state-action space, and unstable value estimates under function approximation.
Learning concept · Not a validated service
On-policy and off-policy methods differ in whether the data used for learning comes from the policy being improved. On-policy learners (for example SARSA or policy-gradient methods) evaluate or improve the policy that generated experience. Off-policy learners (for example Q-learning or importance-sampling-based evaluation) learn about a target policy from data collected by another behaviour policy. Typical error cases include non-stationary rewards, insufficient coverage of the state-action space, and unstable value estimates under function approximation.
A proposed application is to compare learning stability when tuning controllers in simulation, for example checking whether offline logs allow reliable policy improvement before deploying changes to physical hardware. In such uses, keep a human operator in the loop for safety and final decisions.
Specify the state and action spaces, episodic termination rules, reward signal and metrics such as average episodic return, regret and variance across seeds.
Generate experience under different behaviour policies (e.g. exploratory vs greedy) and separate datasets for on-policy training and offline evaluation.
Fit simple on-policy and off-policy algorithms (SARSA, Q-learning or REINFORCE vs DQN) and log reward curves and stability across seeds.
Compare average return, convergence speed and failure modes such as divergence, high variance or poor coverage of rare states.
The supplied starter simulates a 4-armed Bernoulli bandit using an epsilon-greedy online loop: it samples actions, observes binary rewards drawn from fixed true reward rates, updates incremental sample-average estimates and prints counts, estimates and total reward. It does not implement episodic environments, off-policy evaluation, or explicit on-policy/off-policy algorithm comparisons.
for step in range(1, 2001):
if rng.random() < epsilon:
action = rng.integers(len(true_reward_rates))
else:
action = int(np.argmax(estimated_values))
reward = 1 if rng.random() < true_reward_rates[action] else 0
action_counts[action] += 1
total_reward += reward
estimated_values[action] += (reward - estimated_values[action]) / action_counts[action]The code runs a simple epsilon-greedy bandit update and does not implement any off-policy algorithm, episodic environment, policy-gradient method, or off-policy evaluation technique named by the project title.
Proposed extension: run comparable on-policy (SARSA or REINFORCE) and off-policy (Q-learning or DQN) learners on a Gymnasium environment such as CartPole, using seeded repeats and logging average return, regret and variance to compare stability.
This is a potential application pathway, not a delivered product. The supplied starter does not implement this service or validate it with real users.
Networkers Home runs this topic inside its AI Engineer Course, with placement support and hands-on labs.