def test_hubbard_square_lattice_edge_types():
lattice = HubbardSquareLattice(3, 3)
assert sorted(lattice.edge_types) == sorted(
('onsite', 'neighbor', 'vertical_neighbor', 'horizontal_neighbor'))
lattice.validate_edge_type('onsite')
lattice.validate_edge_type('neighbor')
with pytest.raises(ValueError):
lattice.validate_edge_type('banana')
with pytest.raises(ValueError):
lattice.site_pairs_iter('banana')
def test_hubbard_square_lattice(x_dimension, y_dimension, n_dofs, spinless,
periodic):
lattice = HubbardSquareLattice(x_dimension,
y_dimension,
n_dofs=n_dofs,
spinless=spinless,
periodic=periodic)
n_spin_values = 2 - spinless
sites = tuple(
(x, y)
for y, x in itertools.product(range(y_dimension), range(x_dimension)))
site_indices = tuple(lattice.to_site_index(site) for site in sites)
assert (sites == tuple(
lattice.from_site_index(site_index) for site_index in site_indices))
assert (site_indices == tuple(lattice.site_indices) == tuple(
range(x_dimension * y_dimension)))
tuple(
itertools.product(range(x_dimension), range(y_dimension),
range(n_dofs), range(n_spin_values)))
spin_orbital_linear_indices = tuple(
lattice.to_spin_orbital_index(*indices)
for indices in itertools.product(site_indices, range(n_dofs),
range(n_spin_values)))
assert spin_orbital_linear_indices == tuple(range(lattice.n_spin_orbitals))
for i, ii in zip(range(lattice.n_sites),
lattice.site_pairs_iter('onsite')):
assert ii == (i, i)
n_neighbor_pairs = 2 * ((x_dimension * (y_dimension - (not periodic))) +
((x_dimension - (not periodic)) * y_dimension))
neighbor_pairs = tuple(lattice.site_pairs_iter('neighbor'))
assert (2 * len(tuple(lattice.site_pairs_iter('neighbor', False))) ==
len(neighbor_pairs) == n_neighbor_pairs)
for i, j in neighbor_pairs:
assert sum(lattice.delta_mag(i, j, True)) == 1
assert len(tuple(
lattice.dof_pairs_iter(False))) == n_dofs * (n_dofs + 1) / 2
assert len(tuple(
lattice.dof_pairs_iter(True))) == n_dofs * (n_dofs - 1) / 2
spin_pairs_all = tuple(lattice.spin_pairs_iter())
assert len(spin_pairs_all) == n_spin_values**2
spin_pairs_same = tuple(lattice.spin_pairs_iter(SpinPairs.SAME))
assert spin_pairs_same == tuple((s, s) for s in range(n_spin_values))
spin_pairs_diff = tuple(lattice.spin_pairs_iter(SpinPairs.DIFF))
assert spin_pairs_diff == () if spinless else ((0, 1), (1, 0))
def test_hubbard_square_lattice_1xd(d):
for shape, periodic in itertools.product(((1, d), (d, 1)), (True, False)):
lattice = HubbardSquareLattice(*shape, periodic=periodic)
assert lattice.n_sites == d
assert (len(tuple(lattice.neighbors_iter())) ==
2 * len(tuple(lattice.neighbors_iter(False))) == 2 *
(d - (not periodic)))
assert (len(tuple(lattice.diagonal_neighbors_iter())) == len(
tuple(lattice.diagonal_neighbors_iter(False))) == 0)
assert (len(tuple(lattice.site_pairs_iter('diagonal_neighbor'))) == len(
tuple(lattice.diagonal_neighbors_iter(False))) == 0)