in
  B(i+1:m,i), and tau in B(i,i).

  Each F(i) has the form

        F(i) = I - nu * v * v'

  where nu is a real scalar, and v is a real vector with
  v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in
  A(i+1:m,i), and nu in TAU(i).

  Each G(i) is a Givens rotation acting on rows i of A and B,
  where the cosine is stored in CS(2*i-1) and the sine in
  CS(2*i).

</PRE>
<A name="References"><B><FONT SIZE="+1">References</FONT></B></A>
<PRE>
  [1] Bunse-Gerstner, A.
      Matrix factorizations for 