Function gemv 

pub fn gemv<T: SimdOps>(
    a: &[T],
    x: &[T],
    y: &mut [T],
    nrows: usize,
    ncols: usize,
) -> Result<(), SimdError>

Computes register-blocked GEMV y += A · x with runtime backend selection.

a is row-major nrows × ncols; the product accumulates into y (zero y first for y = A·x). See gemv() for the operand-reuse theorem.

Errors

SimdError::LengthMismatch if a.len() < nrows·ncols, x.len() < ncols, or y.len() < nrows.