tude of the largest entry
          in X.
          If N = 0 or X = 0, FERR is set to 0.
          If JOB = 'C', FERR is not referenced.

</PRE>
<B>Workspace</B>
<PRE>
  IWORK   INTEGER array, dimension (N*N)

  DWORK   DOUBLE PRECISION array, dimension (LDWORK)
          On exit, if INFO = 0 or INFO = N+1, DWORK(1) returns the
          optimal value of LDWORK.

  LDWORK  INTEGER
          The dimension of the array DWORK.
          Let LWA = N*N, if LYAPUN = 'O';
              LWA = 0,   otherwise,
      