symplectic QR-like methods.
      Linear Algebra Appl., 83, pp. 49-77, 1986.

  [2] Byers, R.
      Hamiltonian and Symplectic Algorithms for the Algebraic
      Riccati Equation.
      Ph.D. Dissertation, Center for Applied Mathematics,
      Cornell University, Ithaca, NY, 1983.

</PRE>
<A name="Numerical Aspects"><B><FONT SIZE="+1">Numerical Aspects</FONT></B></A>
<PRE>
  The algorithm requires
     8*M*N*N - 8/3*N*N*N +  2*M*N + 6*N*N + 8/3*N,  if M &gt;= N,
     8*M*M*N - 8/3*M*M*M + 14*M*N - 6*M*M + 8