Function decompose_hessenberg_3 

pub fn decompose_hessenberg_3<S: Real>(
    m: Matrix3<S>,
) -> Option<(Matrix3<S>, UpperHessenberg3<S>)>

Returns matrices (q, h) of the decomposition m = qhq^T where q is an orthogonal matrix and h is an upper-Hessenberg matrix.

Returns None if m is the zero matrix:

let mat = Matrix3::<f32>::zero();
assert_eq!(decompose_hessenberg_3 (mat), None);