A = fd3d(7,5,1,0,0,0,0);
n = size(A,1);
lam = eig(full(A));
lam = sort(lam);
figure(1);
hold on;
for i=1:n
  plot([1, n],[lam(i), lam(i)],'r-')
end 
v = randn(n,1);
[V, T] = lancz(v, A, n);
for i=4:3:n
    lamt = eig(T(1:i,1:i));
    plot(i*ones(i,1), lamt, 'o','linewidth',2);
    pause(0.25)
end
