Research notebook

What PPO Clipping Actually Limits notebook

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What PPO Clipping Actually Limits

The clipped surrogate removes incentives in one direction at a time. It does not enforce a hard probability-ratio or KL bound.

Original objective-value and categorical-KL calculation; no PPO training, optimizer run, or control benchmark.

The code uses Python 3 and the standard library. Saved output is from the checked CPU run.

Python · cell 1
r=0.6: A=+2 -> 1.2, A=-2 -> -1.6
r=0.8: A=+2 -> 1.6, A=-2 -> -1.6
r=1.0: A=+2 -> 2.0, A=-2 -> -2.0
r=1.2: A=+2 -> 2.4, A=-2 -> -2.4
r=1.4: A=+2 -> 2.4, A=-2 -> -2.8
candidate_ratio=1.80, objective=1.20
KL(old||new)=0.510826 nats

Sources

  • Proximal Policy Optimization Algorithms: https://arxiv.org/pdf/1707.06347

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