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Pareto Frontier

Lodri Péter edited this page Jun 25, 2026 · 1 revision

Pareto Frontier

The must-keep loss weight λ controls the precision–compression tradeoff. v8's training data held constant; only λ varies.

The frontier

λ Model Heretic exact Compression keep_rate Status
3.0 v8 0.955 15.0% 0.854 Production (sweet spot)
5.0 v17 0.963 3.7% 0.963 Pareto middle
10.0 v16 0.972 2.8% 0.972 Best precision, near-zero compression

Interpretation

  • Each +1.0 in λ buys ~0.01 heretic precision at ~10% compression cost
  • At λ=10, the model keeps 97.2% of tokens — useless as a compressor despite the best precision
  • λ=3 (v8) is the knee of the curve: 0.955 heretic with 15% compression

Why λ=3 is the production choice

In headroom (the production compression infrastructure), compression aggressiveness matters for context-window savings. λ=3 gives the best tradeoff: meaningful compression (15%) with high must-keep survival (0.955 heretic, 1.000 agent mk_in_ref with override).

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