Function hadamard_blocked_rows 

pub fn hadamard_blocked_rows(
    data: &mut [f32],
    rows: usize,
    cols: usize,
    seed: Option<i64>,
    inverse: bool,
) -> Result<(), EngineError>

Apply blocked Hadamard on rows of a row-major [rows, cols] matrix. inverse=false → per-block H@S; inverse=true → S@H.

Tile sizes default to greedy pow2_tile_sizes (Python pow2_tile_blocks).