def test_with_qubits():
old_qubits = cirq.LineQubit.range(9)
new_qubits = cirq.LineQubit.range(9, 18)
qubit_pauli_map = {q: cirq.Pauli.by_index(q.x) for q in old_qubits}
pauli_string = cirq.PauliString(qubit_pauli_map, negated=True)
assert (cirq.PauliStringExpectation(pauli_string).with_qubits(
*new_qubits) == cirq.PauliStringExpectation(
pauli_string.with_qubits(*new_qubits)))
assert (cirq.ApproxPauliStringExpectation(
pauli_string, num_samples=1).with_qubits(
*new_qubits) == cirq.ApproxPauliStringExpectation(
pauli_string.with_qubits(*new_qubits), num_samples=1))
def test_run_ignore_displays(dtype):
simulator = cirq.DensityMatrixSimulator(dtype=dtype)
q0 = cirq.LineQubit(0)
display = cirq.ApproxPauliStringExpectation(cirq.PauliString({q0: cirq.Z}),
num_samples=1)
circuit = cirq.Circuit.from_ops(cirq.X(q0), display, cirq.measure(q0))
result = simulator.run(circuit)
assert result.measurements['0'] == [[True]]
def test_pauli_string_expectation_helper():
qubits = cirq.LineQubit.range(9)
qubit_pauli_map = {q: cirq.Pauli.by_index(q.x) for q in qubits}
pauli_string = cirq.PauliString(qubit_pauli_map, negated=True)
assert (cirq.pauli_string_expectation(
pauli_string, key='a') == cirq.PauliStringExpectation(pauli_string,
key='a'))
assert (cirq.pauli_string_expectation(
pauli_string,
5, key='a') == cirq.ApproxPauliStringExpectation(pauli_string,
5,
key='a'))
def test_properties():
qubits = cirq.LineQubit.range(9)
qubit_pauli_map = {q: cirq.Pauli.by_index(q.x) for q in qubits}
pauli_string = cirq.PauliString(qubit_pauli_map, negated=True)
pauli_string_expectation = cirq.PauliStringExpectation(pauli_string,
key='a')
assert pauli_string_expectation.qubits == tuple(qubits)
assert pauli_string_expectation.key == 'a'
approx_pauli_string_expectation = cirq.ApproxPauliStringExpectation(
pauli_string, num_samples=5, key='a')
assert approx_pauli_string_expectation.qubits == tuple(qubits)
assert approx_pauli_string_expectation.num_samples == 5
assert approx_pauli_string_expectation.key == 'a'
def test_approx_pauli_string_expectation_measurement_basis_change(paulis):
qubits = cirq.LineQubit.range(2)
display = cirq.ApproxPauliStringExpectation(cirq.PauliString({
qubits[0]:
paulis[0],
qubits[1]:
paulis[1]
}),
num_samples=1)
matrix = np.kron(cirq.unitary(paulis[0]), cirq.unitary(paulis[1]))
circuit = cirq.Circuit.from_ops(display.measurement_basis_change())
unitary = circuit.to_unitary_matrix(qubit_order=qubits)
ZZ = np.diag([1, -1, -1, 1])
np.testing.assert_allclose(
np.dot(unitary, np.dot(matrix, unitary.T.conj())), ZZ)
def test_approx_pauli_string_expectation_value(measurements, value):
display = cirq.ApproxPauliStringExpectation(cirq.PauliString({}),
num_samples=1)
assert display.value_derived_from_samples(measurements) == value