ppo

Trace the full arc of Reinforcement Learning from Human Feedback — preference data, Bradley-Terry reward models, PPO with KL penalty, reward hacking, and why most labs have moved to offline alternatives like DPO and RAFT.

An honest map of RL in 2026 — the domains where it actually reaches production (LLM post-training, robotics policies, ad bidding, RLHF, reasoning models) and the places where it still cannot reliably cross the lab-to-deployment gap.

A deep dive into how raw pretrained language models become helpful assistants — from supervised fine-tuning on curated demonstrations, through reward modeling and PPO-based RLHF, to modern direct alignment methods like DPO and the recipes used in Llama 3, Llama 4, and DeepSeek.

Tabular methods break down when the state space is continuous or astronomical in size. Learn how neural networks extend RL via DQN, how the policy gradient theorem makes it possible to differentiate through stochastic policies, and where actor-critic, PPO, and the deadly triad fit into the picture.