def test_from_dense(self):
psi = qu.rand_ket(2**8)
mps = MatrixProductState.from_dense(psi, dims=[2] * 8)
assert mps.tags == {'I{}'.format(i) for i in range(8)}
assert mps.site_inds == tuple('k{}'.format(i) for i in range(8))
assert mps.nsites == 8
mpod = mps.to_dense()
assert qu.expec(mpod, psi) == pytest.approx(1)
def test_matrix_product_state(self):
tensors = ([np.random.rand(5, 2)] +
[np.random.rand(5, 5, 2)
for _ in range(3)] + [np.random.rand(5, 2)])
mps = MatrixProductState(tensors)
assert len(mps.tensors) == 5
nmps = mps.reindex_sites('foo{}', inplace=False, where=slice(0, 3))
assert nmps.site_ind_id == "k{}"
assert isinstance(nmps, MatrixProductState)
assert set(nmps.outer_inds()) == {'foo0', 'foo1', 'foo2', 'k3', 'k4'}
assert set(mps.outer_inds()) == {'k0', 'k1', 'k2', 'k3', 'k4'}
mps.site_ind_id = 'foo{}'
assert set(
mps.outer_inds()) == {'foo0', 'foo1', 'foo2', 'foo3', 'foo4'}
assert mps.site_inds == ('foo0', 'foo1', 'foo2', 'foo3', 'foo4')
assert mps.site_ind_id == 'foo{}'
mps.show()
def test_right_canonize_site(self):
a = np.random.randn(7, 2) + 1.0j * np.random.randn(7, 2)
b = np.random.randn(7, 7, 2) + 1.0j * np.random.randn(7, 7, 2)
c = np.random.randn(7, 2) + 1.0j * np.random.randn(7, 2)
mps = MatrixProductState([a, b, c], site_tag_id="I{}")
mps.right_canonize_site(2)
assert mps['I2'].shape == (2, 2)
assert mps['I2'].tags == {'I2'}
assert mps['I1'].tags == {'I1'}
U = (mps['I2'].data)
assert_allclose(U.conj().T @ U, np.eye(2), atol=1e-13)
assert_allclose(U @ U.conj().T, np.eye(2), atol=1e-13)
# combined two site contraction is identity also
mps.right_canonize_site(1)
ptn = (mps.H & mps) ^ ['I1', 'I2']
assert_allclose(ptn['I1'].data, np.eye(4), atol=1e-13)
# try normalizing the state
mps['I0'] /= mps['I0'].norm()
assert_allclose(mps.H @ mps, 1)