PEARL A — First-observation bootstrap: eliminates Xavier-derived
formulas (2.33 z-score, √2 std, √(2/K_in)) from the bootstrap section.
Sentinel ISV[X]=0 at fold reset; producer step 0 detects sentinel,
replaces directly with step_observation. Subsequent steps EMA-blend.
Consumer cold-start safety via .max(1.0) numerical floor only (Adam-ε
category, not magnitude). Truly zero magnitude constants in bootstrap.
PEARL B — Fused per-param-group statistics oracle: producer count
36 → 14. Per-group fused kernel reads (params, grads, adam_m, adam_v)
once and computes WEIGHT_BOUND, ADAM_M_BOUND, ADAM_V_BOUND, WD_RATE
in one multi-pass operation. Trunk's oracle adds Pass E for L1_LAMBDA
gradient-direction entropy. 4× memory bandwidth reduction. Cleaner
conceptual unit (per-param-group bounds = one oracle).
PEARL C — Engagement-rate self-correction: detects post-clamp
feedback-loop saturation. For in-kernel clamps, theoretical engagement
rate = 1% (top 1% by p99 definition). Producer-side rate-deficit EMA
detects sustained deviation; force-bumps bound to step_max when
detected. Resolves the "in-kernel feedback loop accepted" limitation
from first draft. Per-Adam-kernel block-shared-memory engagement
counter (no atomicAdd), block-wide reduce, host-side rate-deficit EMA.
PEARL D — Wiener-optimal adaptive α: replaces all hardcoded EMA rates
across 14 new producers AND 7 existing pre-SP4 producers. Per-step:
α* = diff_var / (diff_var + sample_var + ε_num). Theoretically optimal
under Wiener-filter analysis; subsumes Pearl A as t=0 edge case
(both vars=0 → α=1 → first-observation replacement). On stationary
signals: α→0 (smooth). On non-stationary: α→1 (track). Eliminates
the recursion problem (α controlled by signal stats, not another α).
ε_num = 1e-8 (Adam-ε numerical category). 3 floats of state per
producer. 36+ hardcoded α values eliminated codebase-wide.
Limitations section restructured: 6 of 8 first-draft limitations
RESOLVED by pearls (in-kernel feedback loop, smoke time-budget,
producer plumbing, stale-bound, 8 carved-out items, magnitude bootstrap
formulas). Remaining 6 limitations are genuinely irreducible (F0
launch-scheduling variance, Layer B atomic flip risk, novel-pearl
field-validation, equilibrium-formula non-stationarity, Pearl C
counter-state cost, Pearl D state cost).
SP4 now closes 100% of the magnitude/regularization/EMA-rate surface.
No hardcoded scalars remain in the entire bound/clamp/EMA chain.
Producer count: 14. ISV slot count: 36. Unit tests: 36.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
074b4f0865