ngrid = [2**n for n in range(2, 10, 1)]
n_exact = 20
e_exact = ho.get_energy(np.arange(n_exact))
columns = []
pd.set_option('display.precision', 8)
for nn in ngrid:
xmin, xmax = -10, 10
x = np.linspace(xmin, xmax, nn)
v = ho.get_potential(x)
es = Eigenstates1D(mass=1.0, grid=x, potential=v)
es.compute_hamiltonian()
energies, psi = es.get_eigenstates()
df = pd.DataFrame({'Ngrid = ' + str(nn) : energies})
columns.append(df)
df_exact = pd.DataFrame({'Exact' : e_exact})
columns.append(df_exact)
table_ho = pd.concat(columns, axis = 1)
table_ho.index.names = ['n']
table_ho.head(20)