flowchart LR
  Q0([GSM8K prompts]):::data --> Q1["rollout<br/>generate + log-probs"]:::model --> Q2["score<br/>verifier or reward model"]:::rl --> Q3["+ per-token KL to ref"]:::rl --> Q4["GAE<br/>advantages + returns"]:::proc --> Q5["clipped policy + value<br/>(K epochs)"]:::model --> Q6[(ppo.pt)]:::ckpt
  Q5 -. sync old policy .-> Q1

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  classDef store fill:#cfeee9,stroke:#1f9e8f,stroke-width:2px,color:#0c3a34;
  classDef proc fill:#cfe3fb,stroke:#1565c0,stroke-width:2px,color:#0d2c52;
  classDef model fill:#ffe8a3,stroke:#d48806,stroke-width:2px,color:#5a3d00;
  classDef rl fill:#ffd9b3,stroke:#e67e22,stroke-width:2px,color:#6b3500;
  classDef loss fill:#ffd4d4,stroke:#c0392b,stroke-width:2px,color:#5c1212;
  classDef ckpt fill:#ececec,stroke:#666666,stroke-width:2px,color:#222222;
  classDef eval fill:#e7d6fb,stroke:#8e44ad,stroke-width:2px,color:#3d1a5a;
  classDef out fill:#e7d6fb,stroke:#7b3fbf,stroke-width:2px,color:#3d1a5a;
  classDef op fill:#ffffff,stroke:#888888,stroke-width:2px,color:#333333;