Function angular_legendre 

fn angular_legendre<const N: usize>(
    l: i32,
    m: i32,
    z: Jet<N>,
    power: i32,
) -> Jet<N>

F_l^m(z) sin(theta)^power: the Legendre function for power = |m|, and pi / m for power = |m| - 1.