Function zeta_impl 

pub fn zeta_impl<P, E, V, const ZETAC: bool>(s: V) -> V
where
    E: FloatElement + ZetaConsts + BernoulliNumbers,
    V: FloatVector<Element = E> + SpecializedTranscendentalMath<E> + SpecializedSpecialMath<E>,
    P: Policy,

zeta(s) (ZETAC = false) or zeta(s) - 1 (ZETAC = true), for real s.