Post-mortem of the H6 Phase 1 smoke (WR = 50.21% verdict in
`docs/dqn-wire-up-audit.md`) traced an actual pearl violation in the
H6 implementation itself: state slot 121 uses the [0, 1] range
(`aux_softmax[env, 1] = p_up`) with sentinel 0.5, while every OTHER
state slot uses 0 as the "no signal" baseline (zero-padding,
feature_mask, ofi-missing, mtf-missing).
Per `pearl_first_observation_bootstrap`: "sentinel = 0; first
observation replaces directly." The H6 design violated this for
slot 121 alone. The encoder must learn TWO things about slot 121:
(1) the directional mapping AND (2) the appropriate bias offset for
the non-zero baseline — every other dim is single-step (mapping only).
Phase 2 is the simplest possible amplification fix: rewrite the bridge
to use the same convention as every other state slot. If the encoder
can't gradient-couple even after this fix, H6 is truly falsified and
we pivot to amplitude scaling or deeper hypothesis.
Change scope (atomic per `feedback_no_partial_refactor`):
- aux_softmax_to_per_env_kernel.cu: write `2*p_up - 1` instead of `p_up`
- gpu_experience_collector.rs: cold-start + FoldReset sentinel 0.5 → 0.0
- experience_kernels.cu: NULL-fallback in 3 state-gather kernels
0.5f → 0.0f
- state_layout.rs / state_layout.cuh: comment updates to reflect
[-1, +1] range and 0 sentinel
Estimated effort: ~45 min walltime (edits + verification gates) +
~25–40 min smoke wall-clock.
Verdict criteria (cycle 1 WR + a_var [d/m/o/u] in HEALTH_DIAG[0]):
- WR > 50.5% → recentering binding, H6 + Phase 2 sufficient → justify A2
- a_var for mag/ord/urg > 1e-3 → sub-branches learning under recentered signal
- WR pinned at 50.1–50.2% → Phase 2 falsified, pivot to amplitude
scaling or deeper hypothesis
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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