ray contains
          the updated matrix B.
          If L = 0, this array is not referenced.

  LDB     INTEGER
          The leading dimension of array B.  LDB &gt;= MAX(1,L).

  TAU     (output) DOUBLE PRECISION array, dimension MIN(N,M)
          The scalar factors of the elementary reflectors used.

</PRE>
<B>Workspace</B>
<PRE>
  DWORK   DOUBLE PRECISION array, dimension (LDWORK)
          On exit, if INFO = 0, DWORK(1) returns the optimal value
          of LDWORK.

  LDWORK  The length of the array