def test_correlation(self):
ghz = (MPS_computational_state('0000') +
MPS_computational_state('1111')) / 2**0.5
assert ghz.correlation(qu.pauli('Z'), 0, 1) == pytest.approx(1.0)
assert ghz.correlation(qu.pauli('Z'), 1, 2) == pytest.approx(1.0)
assert ghz.correlation(qu.pauli('Z'), 3, 1) == pytest.approx(1.0)
assert ghz.correlation(qu.pauli('Z'), 3, 1,
B=qu.pauli('Y')) == pytest.approx(0.0)
assert ghz.H @ ghz == pytest.approx(1.0)
def test_solve_bigger(self):
n = 14
chi = 16
ham = MPO_ham_mbl(n, dh=8, seed=42)
p0 = MPS_computational_state('00110111000101')
dmrgx = DMRGX(ham, p0, chi)
assert dmrgx.solve(tol=1e-5, sweep_sequence='R')
assert dmrgx.state[0].dtype == float
def test_auto_split_detection(self):
psi0 = MPS_computational_state('00')
CNOT = qu.controlled('not')
ISWAP = qu.iswap()
G = qu.rand_uni(4)
opts = {'contract': 'auto-split-gate', 'where': (0, 1)}
psi_cnot = psi0.gate(CNOT, **opts)
psi_iswap = psi0.gate(ISWAP, **opts)
psi_G = psi0.gate(G, **opts)
assert (psi_cnot.max_bond() == psi_iswap.max_bond() ==
psi_G.max_bond() == 2)
assert len(psi_cnot.tensors) == len(psi_iswap.tensors) == 4
assert len(psi_G.tensors) == 3
def test_gate_swap_and_split(self):
n = 10
p = MPS_computational_state('0' * n)
assert p.bond_sizes() == [1] * (n - 1)
G = qu.rand_uni(4)
p.gate_(G, (1, n - 2), contract='swap+split')
assert p.bond_sizes() == [1] + [2] * (n - 3) + [1]
def test_magnetization(self):
binary = [0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1]
p = MPS_computational_state(binary)
mzs = [p.magnetization(i) for i in range(len(binary))]
assert_allclose(mzs, 0.5 - np.array(binary))
