Critical bug: checkpoint weights are (N_packed, K_packed) N-major format,
but make_b_k_major expects (E, K_packed, N_packed) input. Without the
permute, the K and N dimensions are swapped, producing garbage output
with wrong dimensions (e.g., q_a output was 3584 instead of 1536).
Also fix scale assembly: checkpoint scales are (N, K_sf) which should
use assemble_raw_scales_2d3d_3d_side (no transpose), not
assemble_scales_3d_side (which incorrectly transposes K_sf↔N).
The CuTeDSL kernel expects float4_e2m1fn_x2 dtype for FP4 weight tensors,
but checkpoint weights from safetensors are loaded as uint8. The uint8 and
float4_e2m1fn_x2 have the same byte representation, so .view() is safe.
Fixed in:
- Nvfp4Linear.finalize_weights()
- Nvfp4SharedExpert.finalize_weights()
- Nvfp4MoE._ensure_stacked() (both stacked and legacy paths)
Critical bug fix: weight_scale_2 (the second-level NVFP4 scale) was
being dropped entirely in the production pipeline. The dequant formula
is lut[w] * weight_scale * weight_scale_2, so weight_scale_2 must be
folded into the GEMM's global_scale_b parameter.
Fixes in:
- Nvfp4Linear: ws2 field, folded in finalize_weights()
- Nvfp4MoE: l1_ws2/l2_ws2 lists, folded in _ensure_stacked()
- Nvfp4SharedExpert: l1_ws2/l2_ws2 lists, folded in finalize_weights()
- single_shot_inference.py: pass weight_scale_2 through all loading paths
- Also fix missing o_a_prod key fallback in attention output
