def theoretical_moment(eigval_m):
    """Compute the theoretical first and 2nd moment for the eigenvalue distribution"""
    dim = len(eigval_m)
    Var = ((eigval_m**2).sum() * dim - eigval_m.sum()**2) * 2 / dim**2 / (dim+2)
    Mean = eigval_m.sum()/dim
    return Mean, Var