The standalone dd_pct_concat_kernel from Phase 1.5 was bottleneck-
incompatible — it operated on raw [B, 128] state, but production trunk
consumes [B, s1_input_dim] = [B, 102] post-bottleneck. Wave 4.1a fixes
this at the kernel level; Wave 4.1b lands the consumer migration
(s1_input_dim 102→103, GRN w_s1 reshape, 3 forward + 3 backward sites).
Spec correction (per feedback_trust_code_not_docs): the spec's
'state_dim 48→49' is stale terminology pre-STATE_DIM 48→112→128
evolution. Production s1_input_dim is bottleneck_dim + (STATE_DIM −
market_dim) = 16 + (128 − 42) = 102. Wave 4.1b will bump this to 103.
NEW bn_tanh_concat_dd_kernel in dqn_utility_kernels.cu:
- Fuses dd_pct append into the same launch as bn_tanh + portfolio
concat (output shape [B, bn_dim + portfolio_dim + 1])
- Reads isv[DD_PCT_INDEX=406] (set by Wave 1.3.b dd_state_kernel
per-step), broadcasts the scalar across batch as the appended
last column
DELETED standalone dd_pct_concat_kernel.cu + launch_sp15_dd_pct_concat
+ cubin manifest entry per feedback_no_legacy_aliases (zero production
callers — only test consumer; bottleneck-on path is canonical).
Test helpers added (used by Wave 4.1c behavioral KL test).
Phase 1.5 oracle test migrated to bn_tanh_concat_dd_kernel contract:
test name bn_tanh_concat_dd_kernel_writes_dd_pct_column passes on
RTX 3050 Ti.
Layout fingerprint already covers Phase 1.5 via the existing
TRUNK_INPUT_DD_PCT=sp15_phase_1_5; marker — pre-SP15 checkpoints
already break.
fxcache schema_hash auto-bumps from file content hashes (per task
P5T5 Phase F mechanism); no manual schema bump needed.
Atomic per feedback_no_partial_refactor for the kernel-signature
contract change. Consumer wiring (s1_input_dim propagation, GRN
reshape, forward/backward call sites) deferred to Wave 4.1b's atomic
commit per the established 3a/3b split precedent — kernel + launcher
land first.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
a8da1cb9cf