Two coupled fixes to the vol-EMA regime detector exposed by walk-forward
CV after all features were promoted to always-on:
(1) Bootstrap window for vol_ref (slot 551 = REGIME_VOL_REF_SAMPLES)
- Replace the Pearl-A "first observation replaces directly" bootstrap
with a running mean over the first N=100 vol_ema observations, then
switch to β-tracking. For IID observations the running-mean estimator
has variance σ²/N — a 100-sample mean is 10× less noisy than the
single-shot replace.
(2) Permanent floor on vol_ref (slot 552 = REGIME_VOL_REF_FLOOR)
- The bootstrap alone exposed the asymmetric deadband-deadlock: if
vol_ref converged to a tiny value during a calm initial stretch,
vol_ref / vol_ema fired the moment any realistic vol resumed and
Kelly stayed trapped at regime_scale_floor=0.25 forever. Floor
lives in ISV slot (TrainingPersist) with a hardcoded 1e-12 sub-floor
inside the kernel as numerical-underflow guard.
- Host seeds slot 552 with 1e-9. Future controller kernel will refine
this from observed cell-level vol minima with cross-fold persistence.
Walk-forward CV on Q1 fxcache (3 folds, window=700K, train_frac=0.6):
cost fold-A fold-B fold-C mean ± SD
0.00 -19.77 +65.04 (100%) +6.45 +17.24 ± 43.42
Fold B turnaround is the headline: -47.64 (bootstrap-only) → +65.04
(bootstrap + floor) confirms the floor is the load-bearing fix.
Cross-fold std-dev compressed 24% at cost=0; mean dropped from +38.94
(pre-defense) to +17.24 (with defense). Classic mean/variance trade.
Block extended to 14 slots (539..=552). Kernel sig: vol_ref_floor
moved from f32 scalar to vol_ref_floor_index i32, so the anchor is
named/addressable in ISV.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
3c035ce1ae