   For good performance, LZWORK must generally be larger.

          If LZWORK = -1, then a workspace query is assumed;
          the routine only calculates the optimal size of the
          ZWORK array, returns this value as the first entry of
          the ZWORK array, and no error message related to LZWORK
          is issued by XERBLA.

  BWORK   LOGICAL array, dimension (N)

</PRE>
<B>Warning Indicator</B>
<PRE>
  IWARN   INTEGER
          = 0:  no warning;
          = 1:  the descriptor system is sin