Function reduced_radial_impl 

pub fn reduced_radial_impl<E, V>(s: V, k: u32, m: u32) -> V
where
    E: FloatElement,
    V: FloatVector<Element = E>,

The reduced radial polynomial $Q_{k,m}(s) = P_k^{(0,m)}(2s - 1)$ at runtime (k, m).

The single-mode counterpart of one column of the batch ladder. Used by zernike_r in place of a general jacobi call: the general form carries runtime alpha/beta and divides the vector once per step, putting a full divide latency in the dependency chain, where this divides small integers in the element type instead.