function rho = spectral_radius(A)
  %
  % Compute the spectral radius of ``A``, which is not necessarily
  % Hermitian.
  %
  % This is slow. Don't use it on big matrices.
  %
  % INPUT:
  %
  %   ``A`` -- The matrix whose spectral radius you want.
  %
  % OUTPUT:
  %
  %   ``rho`` -- The spectral radius of ``A``.
  %
  rho = max(abs(eig(A)));
end
