 DWORK.
          LDWORK &gt;= K + MAX( 2*N, 8*K ).

</PRE>
<B>Warning Indicator</B>
<PRE>
  IWARN   INTEGER
          = 0        :  no warnings;
          = 1,..,N-1 :  A is in periodic Schur form, but the
                        algorithm was not able to reveal information
                        about the eigenvalues from the 2-by-2
                        blocks.
                        ALPHAR(i), ALPHAI(i), BETA(i) and SCAL(i),
                        can be incorrect for i = 1, ..., IWARN+1;
         