YAPUN = 'O';
          LDA &gt;= 1,        if FACT = 'F' and LYAPUN = 'R'.

  T       (input or output) DOUBLE PRECISION array, dimension
          (LDT,N)
          If FACT = 'F', then T is an input argument and on entry,
          the leading N-by-N upper Hessenberg part of this array
          must contain the upper quasi-triangular matrix T in Schur
          canonical form from a Schur factorization of Ac (see
          argument FACT).
          If FACT = 'N', then T is an output argument and on exit,
