Given a 2-by-2 or 3-by-3 matrix H, CLAQR1 sets v to a
      scalar multiple of the first column of the product
      (*)  K = (H - s1*I)*(H - s2*I)
      scaling to avoid overflows and most underflows.
      This is useful for starting double implicit shift bulges
      in the QR algorithm.

N

          N is INTEGER
              Order of the matrix H. N must be either 2 or 3.

H

          H is COMPLEX array, dimension (LDH,N)
              The 2-by-2 or 3-by-3 matrix H in (*).

LDH

          LDH is INTEGER
              The leading dimension of H as declared in
              the calling procedure.  LDH >= N

S1

          S1 is COMPLEX

S2

          S2 is COMPLEX
          S1 and S2 are the shifts defining K in (*) above.

V

          V is COMPLEX array, dimension (N)
              A scalar multiple of the first column of the
              matrix K in (*).

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Karen Braman and Ralph Byers, Department of Mathematics, University of Kansas, USA