from mmf.physics.seq import ScarfII
V = ScarfII(A=3, B=2)
x = np.linspace(-10, 10, 200)
v = V(x)
En = V.E()
plt.plot(x, v, 'k')
for n, E in enumerate(En):
   x_ = x[np.where(v <= E)][[0, -1]]
   line = plt.plot(x_, x_*0 + E, lw=2)
   colour = line[0].get_color()
   psi = V.psi(n)(x)
   psi = psi/np.max(abs(psi))
   plt.plot(x, 2*psi, colour + '-')