def test_position_shift_right(backend):
D, d, N = 4, 2, 6
tensors = [np.ones((1, d, D))] + [np.ones((D, d, D)) for _ in range(N - 2)
] + [np.ones((D, d, 1))]
mps = BaseMPS(tensors, center_position=int(N / 2), backend=backend)
Z = mps.position(N - 1, normalize=True)
np.testing.assert_allclose(Z, 2.828427)
def test_position_no_shift_no_normalization(backend):
D, d, N = 4, 2, 6
tensors = [np.ones((1, d, D))] + [np.ones((D, d, D)) for _ in range(N - 2)
] + [np.ones((D, d, 1))]
mps = BaseMPS(tensors, center_position=int(N / 2), backend=backend)
Z = mps.position(int(N / 2), normalize=False)
np.testing.assert_allclose(Z, 5.656854)
def test_position_no_normalization(backend):
D, d, N = 4, 2, 6
tensors = [np.ones((1, d, D))] + [np.ones((D, d, D)) for _ in range(N - 2)
] + [np.ones((D, d, 1))]
mps = BaseMPS(tensors, center_position=0, backend=backend)
Z = mps.position(len(mps) - 1, normalize=False)
np.testing.assert_allclose(Z, 8192.0)
def test_check_normality_raises_value_error(backend):
backend = backend_factory.get_backend(backend)
tensor = np.ones((2, 3, 2), dtype=np.float64)
tensors = [tensor]
mps = BaseMPS(tensors, backend=backend)
with pytest.raises(ValueError):
mps.check_orthonormality(which="keft", site=0)
def test_apply_two_site_gate(backend_dtype_values):
backend = backend_dtype_values[0]
dtype = backend_dtype_values[1]
D, d, N = 10, 2, 10
tensors = [get_random_np((1, d, D), dtype)
] + [get_random_np((D, d, D), dtype)
for _ in range(N - 2)] + [get_random_np((D, d, 1), dtype)]
mps = BaseMPS(tensors, center_position=0, backend=backend)
gate = get_random_np((2, 2, 2, 2), dtype)
tensor1 = mps.tensors[5]
tensor2 = mps.tensors[6]
mps.apply_two_site_gate(gate, 5, 6)
tmp = np.tensordot(tensor1, tensor2, ([2], [0]))
actual = np.transpose(np.tensordot(tmp, gate, ([1, 2], [2, 3])),
(0, 2, 3, 1))
node1 = tn.Node(mps.tensors[5], backend=backend)
node2 = tn.Node(mps.tensors[6], backend=backend)
node1[2] ^ node2[0]
order = [node1[0], node1[1], node2[1], node2[2]]
res = tn.contract_between(node1, node2)
res.reorder_edges(order)
np.testing.assert_allclose(res.tensor, actual)
def test_different_backends_raises_error():
D, d = 4, 2
tensors = [np.ones((1, d, D))]
mps1 = BaseMPS(tensors, backend='numpy')
mps2 = BaseMPS(tensors, backend='tensorflow')
mps1.nodes = mps1.nodes + mps2.nodes
with pytest.raises(ValueError):
mps1.backend
def test_mps_switch_backend(backend):
D, d, N = 10, 2, 10
tensors = [get_random_np((1, d, D), np.float64)] + [
get_random_np((D, d, D), np.float64) for _ in range(N - 2)
] + [get_random_np((D, d, 1), np.float64)]
mps = BaseMPS(tensors, center_position=0, backend="numpy")
mps.switch_backend(backend)
assert mps.backend.name == backend
def test_get_tensor(backend):
backend = backend_factory.get_backend(backend)
tensor1 = np.ones((2, 3, 2), dtype=np.float64)
tensor2 = 2 * np.ones((2, 3, 2), dtype=np.float64)
tensors = [tensor1, tensor2]
mps = BaseMPS(tensors, backend=backend)
np.testing.assert_allclose(mps.get_tensor(0), tensor1)
np.testing.assert_allclose(mps.get_tensor(1), tensor2)
def test_check_canonical(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mps = BaseMPS(tensors, backend=backend, center_position=2)
np.testing.assert_allclose(mps.check_canonical(), 71.714713)
def test_get_tensor_connector_matrix(backend):
backend = backend_factory.get_backend(backend)
tensor1 = np.ones((2, 3, 2), dtype=np.float64)
tensor2 = 2 * np.ones((2, 3, 2), dtype=np.float64)
connector = backend.convert_to_tensor(np.ones((2, 2), dtype=np.float64))
tensors = [tensor1, tensor2]
mps = BaseMPS(tensors, backend=backend, connector_matrix=connector)
np.testing.assert_allclose(mps.get_tensor(0), tensor1)
np.testing.assert_allclose(mps.get_tensor(1), 2 * tensor2)
def test_normalization(backend):
D, d, N = 10, 2, 10
tensors = [np.random.randn(1, d, D)
] + [np.random.randn(D, d, D)
for _ in range(N - 2)] + [np.random.randn(D, d, 1)]
mps = BaseMPS(tensors, center_position=0, backend=backend)
mps.position(len(mps) - 1)
Z = mps.position(0, normalize=True)
np.testing.assert_allclose(Z, 1.0)
def test_apply_one_site_gate_2(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mps = BaseMPS(tensors, backend=backend, center_position=2)
gate = backend.convert_to_tensor(np.array([[0, 1], [1, 0]], dtype=np.float64))
mps.apply_one_site_gate(gate=gate, site=1)
expected = np.array([[1., -2., 1.], [1., 2., 1.]])
np.testing.assert_allclose(mps.tensors[1][0], expected)
def test_not_implemented():
D, d = 4, 2
tensors = [np.ones((1, d, D)), np.ones((D, d, D))]
mps = BaseMPS(tensors, backend='numpy')
with pytest.raises(NotImplementedError):
mps.save('tmp')
with pytest.raises(NotImplementedError):
mps.right_envs([0])
with pytest.raises(NotImplementedError):
mps.left_envs([0])
with pytest.raises(NotImplementedError):
mps.canonicalize()
def test_measure_local_operator_value_error(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
operator = backend.convert_to_tensor(
np.array([[1, -1], [-1, 1]], dtype=np.float64))
mps = BaseMPS(tensors, backend=backend)
with pytest.raises(ValueError):
mps.measure_local_operator(ops=2 * [operator], sites=[1, 2, 3])
def test_measure_two_body_correlator_value_error(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
operator = backend.convert_to_tensor(
np.array([[1, -1], [-1, 1]], dtype=np.float64))
mps = BaseMPS(tensors, backend=backend)
with pytest.raises(ValueError):
mps.measure_two_body_correlator(
op1=operator, op2=operator, site1=-1, sites2=[2])
def test_apply_one_site_gate(backend_dtype_values):
backend = backend_dtype_values[0]
dtype = backend_dtype_values[1]
D, d, N = 10, 2, 10
tensors = [get_random_np((1, d, D), dtype)
] + [get_random_np((D, d, D), dtype)
for _ in range(N - 2)] + [get_random_np((D, d, 1), dtype)]
mps = BaseMPS(tensors, center_position=0, backend=backend)
tensor = mps.nodes[5].tensor
gate = get_random_np((2, 2), dtype)
mps.apply_one_site_gate(gate, 5)
actual = np.transpose(np.tensordot(tensor, gate, ([1], [1])), (0, 2, 1))
np.testing.assert_allclose(mps.nodes[5].tensor, actual)
def test_backend_initialization_raises(backend):
be = backend_factory.get_backend(backend)
D, d, N = 10, 2, 10
tensors = [np.random.randn(1, d, D)
] + [np.random.randn(D, d, D)
for _ in range(N - 2)] + [np.random.randn(D, d, 1)]
with pytest.raises(
ValueError,
match="`center_position = 10` is different from `None` and "
"not between 0 <= center_position < 10"):
BaseMPS(tensors, center_position=N, backend=be)
with pytest.raises(
ValueError,
match="`center_position = -1` is different from `None` and "
"not between 0 <= center_position < 10"):
BaseMPS(tensors, center_position=-1, backend=be)
def test_apply_transfer_operator_right(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mat = backend.convert_to_tensor(
np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype=np.float64))
mps = BaseMPS(tensors, backend=backend)
expected = np.array([[80., -20., 128.], [-20., 10., -60.], [144., -60.,
360.]])
actual = mps.apply_transfer_operator(site=3, direction=-1, matrix=mat)
np.testing.assert_allclose(actual, expected)
actual = mps.apply_transfer_operator(site=3, direction="r", matrix=mat)
np.testing.assert_allclose(actual, expected)
actual = mps.apply_transfer_operator(site=3, direction="right", matrix=mat)
np.testing.assert_allclose(actual, expected)
def test_different_dtypes_raises_error():
D, d = 4, 2
tensors = [
np.ones((1, d, D), dtype=np.float64),
np.ones((D, d, D), dtype=np.complex64)
]
with pytest.raises(TypeError):
BaseMPS(tensors, backend='numpy')
_tensors = [
np.ones((1, d, D), dtype=np.float64),
np.ones((D, d, D), dtype=np.float64)
]
mps = BaseMPS(_tensors, backend='numpy')
mps.tensors = tensors
with pytest.raises(TypeError):
mps.dtype
def test_apply_transfer_operator_left(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mat = backend.convert_to_tensor(
np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype=np.float64))
mps = BaseMPS(tensors, backend=backend)
expected = np.array([[74., 58., 38.], [78., 146., 102.], [38., 114., 74.]])
actual = mps.apply_transfer_operator(site=3, direction=1, matrix=mat)
np.testing.assert_allclose(actual, expected)
actual = mps.apply_transfer_operator(site=3, direction="l", matrix=mat)
np.testing.assert_allclose(actual, expected)
actual = mps.apply_transfer_operator(site=3, direction="left", matrix=mat)
np.testing.assert_allclose(actual, expected)
def test_apply_two_site_gate_2(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mps = BaseMPS(tensors, backend=backend, center_position=2)
gate = backend.convert_to_tensor(
np.array([[[[0., 1.], [0., 0.]], [[1., 0.], [0., 0.]]],
[[[0., 0.], [0., 1.]], [[0., 0.], [1., 0.]]]],
dtype=np.float64))
actual = mps.apply_two_site_gate(
gate=gate, site1=1, site2=2, max_singular_values=1)
np.testing.assert_allclose(actual[0], 9.133530)
expected = np.array([[5.817886], [9.039142]])
np.testing.assert_allclose(np.abs(mps.tensors[1][0]), expected, rtol=1e-04)
expected = np.array([[0.516264, 0.080136, 0.225841],
[0.225841, 0.59876, 0.516264]])
np.testing.assert_allclose(np.abs(mps.tensors[2][0]), expected, rtol=1e-04)
def test_position_raises_error(backend):
D, d, N = 10, 2, 10
tensors = [np.random.randn(1, d, D)
] + [np.random.randn(D, d, D)
for _ in range(N - 2)] + [np.random.randn(D, d, 1)]
mps = BaseMPS(tensors, center_position=0, backend=backend)
with pytest.raises(ValueError,
match="site = -1 not between values"
" 0 < site < N = 10"):
mps.position(-1)
with pytest.raises(ValueError,
match="site = 11 not between values"
" 0 < site < N = 10"):
mps.position(11)
mps = BaseMPS(tensors, center_position=None, backend=backend)
with pytest.raises(
ValueError,
match="BaseMPS.center_position is"
" `None`, cannot shift `center_position`."
"Reset `center_position` manually or use `canonicalize`"):
mps.position(1)
def test_position_truncation(backend):
D, d, N = 10, 2, 10
tensors = [np.ones((1, d, D))] + [np.ones((D, d, D)) for _ in range(N - 2)
] + [np.ones((D, d, 1))]
mps = BaseMPS(tensors, center_position=0, backend=backend)
mps.position(N-1)
mps.position(0, D=5)
assert np.all(np.array(mps.bond_dimensions) <= 5)
def test_position_raises_error(backend):
D, d, N = 10, 2, 10
tensors = [np.random.randn(1, d, D)
] + [np.random.randn(D, d, D)
for _ in range(N - 2)] + [np.random.randn(D, d, 1)]
mps = BaseMPS(tensors, center_position=0, backend=backend)
with pytest.raises(ValueError):
mps.position(-1)
with pytest.raises(ValueError):
mps.position(11)
def test_get_tensor_raises_error(backend):
backend = backend_factory.get_backend(backend)
tensor1 = np.ones((2, 3, 2), dtype=np.float64)
tensor2 = 2 * np.ones((2, 3, 2), dtype=np.float64)
tensors = [tensor1, tensor2]
mps = BaseMPS(tensors, backend=backend)
with pytest.raises(ValueError):
mps.get_tensor(site=-1)
with pytest.raises(IndexError):
mps.get_tensor(site=3)
def test_left_orthonormalization(backend_dtype_values):
backend = backend_dtype_values[0]
dtype = backend_dtype_values[1]
D, d, N = 10, 2, 10
tensors = [get_random_np((1, d, D), dtype)
] + [get_random_np((D, d, D), dtype)
for _ in range(N - 2)] + [get_random_np((D, d, 1), dtype)]
mps = BaseMPS(tensors, center_position=N - 1, backend=backend)
mps.position(0)
mps.position(len(mps) - 1)
assert all(
abs(mps.check_orthonormality('left', site)) < 1E-12
for site in range(len(mps)))
def test_apply_two_site_max_singular_value_not_center_raises_error(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mps = BaseMPS(tensors, backend=backend, center_position=2)
gate = backend.convert_to_tensor(np.ones((2, 2, 2, 2), dtype=np.float64))
with pytest.raises(ValueError):
mps.apply_two_site_gate(gate=gate, site1=3, site2=4, max_singular_values=1)
with pytest.raises(ValueError):
mps.apply_two_site_gate(gate=gate, site1=3, site2=4, max_truncation_err=.1)
def test_apply_one_site_gate_invalid_site_raises_error(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mps = BaseMPS(tensors, backend=backend, center_position=2)
gate = backend.convert_to_tensor(np.ones((2, 2), dtype=np.float64))
with pytest.raises(ValueError):
mps.apply_one_site_gate(gate=gate, site=-1)
with pytest.raises(ValueError):
mps.apply_one_site_gate(gate=gate, site=6)
def test_apply_transfer_operator_invalid_direction_raises_error(backend):
backend = backend_factory.get_backend(backend)
tensor = np.array([[[1., 2., 1.], [1., -2., 1.]],
[[-1., 1., -1.], [-1., 1., -1.]], [[1., 2, 3], [3, 2, 1]]],
dtype=np.float64)
tensors = 6 * [backend.convert_to_tensor(tensor)]
mat = backend.convert_to_tensor(
np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]], dtype=np.float64))
mps = BaseMPS(tensors, backend=backend)
with pytest.raises(ValueError):
mps.apply_transfer_operator(site=3, direction=0, matrix=mat)
with pytest.raises(ValueError):
mps.apply_transfer_operator(site=3, direction="keft", matrix=mat)
def test_physical_dimensions(backend):
D = 3
tensors = [np.ones((1, 2, D)), np.ones((D, 3, D)), np.ones((D, 4, 1))]
mps = BaseMPS(tensors, backend=backend)
assert mps.physical_dimensions == [2, 3, 4]
