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_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_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_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_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)
mps = BaseMPS(tensors, center_position=0, backend=backend)
with pytest.raises(
ValueError,
match="max_truncation_err"):
mps.position(1, max_truncation_err=1.1)
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_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_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)