function u = housevec(x)
%  generate the Householder vector
%
   m = max(abs(x));
   x = x/m;
   n = length(x);
   u = zeros(n,1);
   if x(1) >= 0 
      u(1) = x(1)+norm(x);
   else
      u(1) = x(1)-norm(x);
   end
   u(2:n) = x(2:n);
   u = u/norm(u);