The result: collapse delayed, then terminal
Table with columns: step, 10, 30, 50, 70, 90, 100-150| step | 10 | 30 | 50 | 70 | 90 | 100-150 |
|---|
| val reward | 0.528 | 0.694 | 0.778 | 0.708 | 0.833 | 0.000 |
The no-entropy arm collapsed at step ~80 and self-recovered to 0.972 by
150. This arm survived that window (0.833 at step 90 — its peak, and better
than arm 1 ever was pre-collapse), then collapsed at ~100 with entropy pinned
at 1e-4 and never recovered (1-turn degenerate episodes through 150).
Vanilla PPO on this task lives on a knife's edge around steps 80-120; a 0.01
entropy bonus shifts the edge, it does not remove it.
Files
- root: step_90 policy — the pre-collapse peak (val 0.833), value head
stripped, vLLM-loadable;
value_head.safetensors alongside
checkpoints/step_120/, checkpoints/step_150/ — mid/post-collapse
policies for collapse forensics (val 0.000, 1-turn degenerate greedy mode)
Training setup
Same as arm 1: prime-rl ppo, GAE gamma=1.0 lambda=0.95, clip 0.2, value
coef 0.5, LR 1e-6, batch 64 x group 8, 150 steps, temp 0.7,
symbolic-curriculum-v2 (588 train / 72 val pass@4-mixed tasks), 4x RTX PRO
6000 Blackwell. W&B: https://wandb.ai/krishnapg2315/blog-rl/runs/fc57f9265a2d4ff8aaa80fabcc9058ab