Function eigen_symmetric 

pub fn eigen_symmetric(
    n: usize,
    data: &[f64],
) -> Result<(Vec<f64>, Vec<f64>), LinearAlgebraError>

Eigen-decomposition of a SYMMETRIC row-major n×n matrix via cyclic Jacobi rotations. Returns (eigenvalues, eigenvectors) where eigenvectors is a row-major n×n matrix whose COLUMN j is the unit eigenvector for eigenvalues[j]. Errors if the input is not (within tolerance) symmetric.