3-layer MLP: encoder_out_dim → 256 → 128 → AUX_HIDDEN_DIM. Kaiming-He
weights (Box-Muller from LCG-uniform), zero biases, separate Adam m/v
buffers (12 state tensors). Allocated in trainer constructor — collector
borrows via raw_ptr at wire-up time per existing OFI-embed / q-attn
ownership pattern (no parallel param mirror needed). Not yet wired to
forward/backward — pure allocation per Phase C.2 design.
Topology dimensions resolved against actual codebase:
- encoder_out_dim = config.shared_h1 (= SH1 = 256 in production)
- AUX_HIDDEN_DIM = config.shared_h2 (= SH2 = 256, matches existing aux
head's input dim per aux_heads_kernel.cu:118 `h_s2 [B, SH2]`)
Total params: 65,536 + 256 + 32,768 + 128 + 32,768 + 256 = 131,712.
Audit doc updated per Invariant 7. Phase C.2 of SP14 Layer C
separate-aux-trunk refactor (plan:
docs/superpowers/plans/2026-05-07-sp14-layer-c-separate-aux-trunk.md).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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