text: import numpy as np
  from qmsolve import visualization
  from qmsolve import Hamiltonian, SingleParticle, Eigenstates,Å
  
  
  #interaction potential
  def harmonic_oscillator(particle):
  
  	kx, ky, kz = [0.020]*3 # measured in eV / (Å**2)
  
  	return 0.500 * kx * particle.x**2 +\
  		   0.51 * ky * particle.y**2 +\
  		   0.52 * kz * particle.z**2
  
  
  H = Hamiltonian(particles=SingleParticle(),
                    N=90, potential=harmonic_oscillator, 
                    extent=12*Å, spatial_ndim=3)
  
  
  eigenstates = H.solve( max_states = 32, method ='lobpcg')
  print(eigenstates.energies)
  
  
  visualization = visualization.init_visualization(eigenstates)
  visualization.plot_type = 'contour'
  
  #visualization.plot_eigenstate(0)
  
  #visualization.plot_eigenstate(26)
  visualization.animate()
  