def test_too_much_ram():
qubits = cirq.LineQubit.range(30)
circuit = cirq.testing.random_circuit(qubits=qubits, n_moments=20, op_density=0.8)
op = functools.reduce(operator.mul, [cirq.Z(q) for q in qubits], 1)
with pytest.raises(MemoryError) as e:
ccq.tensor_expectation_value(circuit=circuit, pauli_string=op)
assert e.match(r'.*too much RAM!.*')
def test_tensor_expectation_value():
for _ in range(10):
for width in [2, 3]:
for height in [1, 3]:
for p in [1, 2]:
rs = np.random.RandomState(52)
circuit, qubits = _get_circuit(width=width,
height=height,
p=p,
rs=rs)
operator = cirq.PauliString(
{
q: cirq.Z
for q in rs.choice(qubits, size=2, replace=False)
},
coefficient=rs.uniform(-1, 1),
)
eval_tn = ccq.tensor_expectation_value(circuit, operator)
wfn = cirq.Simulator().simulate(circuit)
eval_normal = operator.expectation_from_state_vector(
wfn.final_state_vector, wfn.qubit_map)
assert eval_normal.imag < 1e-6
eval_normal = eval_normal.real
np.testing.assert_allclose(eval_tn, eval_normal, atol=1e-3)
def test_tensor_expectation_value():
rs = np.random.RandomState(52)
for _ in range(10):
for n_qubit in [2, 7]:
qubits = cirq.LineQubit.range(n_qubit)
for depth in [10, 20]:
circuit = cirq.testing.random_circuit(
qubits=qubits, n_moments=depth, op_density=0.8, random_state=rs
)
operator = _random_pauli_string(qubits, rs, coefficients=True)
eval_tn = ccq.tensor_expectation_value(circuit, operator)
wfn = cirq.Simulator().simulate(circuit)
eval_normal = operator.expectation_from_state_vector(
wfn.final_state_vector, wfn.qubit_map
)
assert eval_normal.imag < 1e-6
eval_normal = eval_normal.real
np.testing.assert_allclose(eval_tn, eval_normal, atol=1e-3)