Function axpy_rows_batch 

pub fn axpy_rows_batch<T: SimdOps>(
    alphas: &[T],
    x_panel: &[T],
    out: &mut [T],
    row_stride: usize,
    rows: usize,
    depth: usize,
    cols: usize,
) -> Result<(), SimdError>

Fused batched multi-row update: out[row, i] += sum_k alphas[k, row] * x_panel[k, i] via one runtime-dispatched SIMD kernel. alphas is depth-major with rows elements per depth, x_panel is depth-major with cols elements per depth, and out is a row-major strided window.