Plan 4 Task 2c.3a. Build-clean prep commit. Lays down the GRN param-tensor
layout (86 -> 95 tensors) and migrates all 93 padded_byte_offset call
sites + ancillary index references in lockstep. Does NOT swap the trunk
forward — that's Task 2c.3b. Explicit panics at every trunk-forward and
trunk-backward caller ensure any accidental runtime execution fails
loudly rather than producing silent garbage.
Param-tensor reshuffle:
- Delete: W_S1, b_S1, W_S2, b_S2 (old trunk's 4 Linear tensors)
- Insert: 7 h_s1 GRN tensors (W_a, b_a, W_b, b_b, W_residual, gamma, beta)
- Insert: 6 h_s2 GRN tensors (no W_residual — SH1 == SH2 makes residual
identity)
- All tensor indices >= 4 in OLD layout shift +9 in NEW layout
- NUM_WEIGHT_TENSORS 86->95; FIRST_ISV_TENSOR 68->77
layout_fingerprint_seed() updated. New LAYOUT_FINGERPRINT_CURRENT:
0xcf3a24b0a1f70057 (was 0xa504d3c2f275b8af).
Xavier init paths added for the 13 new tensors:
- W matrices (Linear_a, Linear_b, Linear_residual): Xavier
- LayerNorm gamma_h_s1, gamma_h_s2: 1.0
- LayerNorm beta_h_s1, beta_h_s2: 0.0
- All biases (b_a_h_s1, b_b_h_s1, b_a_h_s2, b_b_h_s2): 0.0
Encoder gates: BatchedForward::encoder_forward_only,
BatchedForward::forward_target_raw, BatchedForward::forward_online_f32,
BatchedBackward::backward_full, GpuDqnTrainer::apply_iqn_trunk_gradient,
GpuDqnTrainer::apply_ensemble_diversity_backward all panic at function
entry. Original bodies preserved (with #[allow(unreachable_code,
unused_variables)]) for Task 2c.3b/c to swap GRN forward + backward
in place.
Spectral-norm descriptor (13 matrices): slots [0]/[1] re-mapped to GRN's
w_a_h_s1/w_a_h_s2 — shapes match legacy W_s1/W_s2 exactly, so the
existing spectral-norm constraint transfers cleanly to the GRN's first
Linear. Linear_b / Linear_residual not yet covered (Task 2c.3c).
Smoke intentionally NOT run. Build-clean is the validation. Task 2c.3b
will swap the encoder forward (gpu_grn::GrnBlock::forward); Task 2c.3c
will swap the trunk backward (gpu_grn::GrnBlock::backward) and run smoke.
Validation:
- cargo check --workspace: 11 baseline warnings (unchanged)
- cargo build -p ml --lib: all 58 cubins compile clean
- 93 padded_byte_offset call sites all migrated; spectral_norm
descriptor + branch_w_base + decoder_forward_only + value_head
indices all updated in lockstep per feedback_no_partial_refactor.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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