%
 %  set up matrix
 %
  n = 10; 
 
  [Q,R] = qr(randn(n));
  d = randn(n,1);
  [t,ii] = sort(abs(d));
  d(ii(n)) = 10*d(ii(n-1));
  A = Q*diag(d)*Q';
 %
 %
 pow_rq(A)
 pause

 pow_inf(A)