Define the task and environment
Choose a Gymnasium environment, define states, actions, reward shaping and episode termination rules before training.
Estimate policy and value. Balance exploration and exploitation.
Actor-critic methods combine a parameterised policy (actor) with a value function (critic) to learn decisions from reward feedback. Practical risks include unstable learning, credit assignment over long horizons and sensitivity to reward shaping.
Learning concept · Not a validated service
Actor-critic methods combine a parameterised policy (actor) with a value function (critic) to learn decisions from reward feedback. Practical risks include unstable learning, credit assignment over long horizons and sensitivity to reward shaping.
A proposed classroom pilot: train an actor-critic agent in a simple Gym environment to compare stability and sample efficiency against baseline policy-gradient or value-based agents. For any real control or safety-critical use, keep a human reviewer in the loop and avoid automated deployment.
Choose a Gymnasium environment, define states, actions, reward shaping and episode termination rules before training.
Build separate function approximators (neural networks) for the policy and the value estimate and connect them in a training loop.
Log reward curves, policy entropy and critic loss across random seeds and tune learning rates and advantage normalisation.
Measure average episodic return, variance, and failure modes such as reward hacking, divergence or brittle behaviour under perturbations.
The supplied starter implements a simple epsilon-greedy multi-armed bandit learner: it simulates four Bernoulli arms, selects actions with an epsilon-exploration policy, updates sample-average estimates for each arm, and prints action counts, estimated rates and total reward. It does not implement an actor network, a critic/value approximator, policy gradients, or interaction with a Gym environment.
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 is a bandit simulation using sample-average value estimates and epsilon-greedy action selection. It lacks any actor (policy parameterisation) and critic (value network) components, no neural networks or bootstrapped returns are present, and there is no episodic environment or state representation required by actor-critic algorithms.
Proposed extension: replace the bandit loop with an agent that interacts with a Gym environment, implement separate actor and critic networks (e.g. small MLPs), train with an advantage estimator and log reward curves across multiple seeds.
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.