Let
  epsilon = 1e-6
  k = 8
  Omega = [-20, 20]^3
  r = x -> sqrt(x_0^2 + x_1^2 + x_2^2)
  g = x -> exp(-2*r(x))
  v = x -> -2/r(x)
In
  nu = F v  
  phi = F g
  lambda = -1.0
  for i in [0,13]
    phi = phi * ||phi||^-1
    V = nu - del^-2 4 * pi * phi^2
    psi = -2 * (-2*lambda - del^2)^-1 V * phi
    lambda = lambda + <V*phi|psi - phi> / <psi|psi>
    phi = psi
    print "iter", i, "norm", ||phi||, "eval",lambda
  end
End



