Function nvfp4_tc_lean_repack 

pub fn nvfp4_tc_lean_repack(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    packed: DevicePtr,
    scale: DevicePtr,
    n: u32,
    k: u32,
    bad: DevicePtr,
    stream: u64,
) -> Result<()>

2026-09-27: Grouped NVFP4 down over the SiLU product. k is the intermediate width; rows of act and output are sorted positions, rows of sh_act and sh_down_out tokens. 2026-10-04: Repacks one row-major NVFP4 matrix [n, k] (packed E2M1 [n, k / 2] at packed, E4M3 block scales [n, k / 16] at scale) in place into the lean layout the _lean tensor-core expert kernels read (nvfp4_tc_lean_repack, moe_nvfp4_grouped_tc.cu): same bytes and size, outputs byte-identical to the row-major point. Sets the device u32 at bad (zeroed by the caller) on a negative or NaN scale, after which the matrix is unusable. Needs nvfp4_lean_repack_shape_ok.