def test_readout_noise_after_moment():
program = cirq.Circuit()
qubits = cirq.LineQubit.range(3)
program.append([
cirq.H(qubits[0]),
cirq.CNOT(qubits[0], qubits[1]),
cirq.CNOT(qubits[1], qubits[2])
])
program.append(
[
cirq.measure(qubits[0], key='q0'),
cirq.measure(qubits[1], key='q1'),
cirq.measure(qubits[2], key='q2'),
],
strategy=cirq.InsertStrategy.NEW_THEN_INLINE,
)
# Use noise model to generate circuit
depol_noise = ccn.DepolarizingNoiseModel(depol_prob=0.01)
readout_noise = ccn.ReadoutNoiseModel(bitflip_prob=0.05)
noisy_circuit = cirq.Circuit(depol_noise.noisy_moments(program, qubits))
noisy_circuit = cirq.Circuit(
readout_noise.noisy_moments(noisy_circuit, qubits))
# Insert channels explicitly
true_noisy_program = cirq.Circuit()
true_noisy_program.append([cirq.H(qubits[0])])
true_noisy_program.append(
[
cirq.DepolarizingChannel(0.01).on(q).with_tags(ops.VirtualTag())
for q in qubits
],
strategy=cirq.InsertStrategy.NEW_THEN_INLINE,
)
true_noisy_program.append([cirq.CNOT(qubits[0], qubits[1])])
true_noisy_program.append(
[
cirq.DepolarizingChannel(0.01).on(q).with_tags(ops.VirtualTag())
for q in qubits
],
strategy=cirq.InsertStrategy.NEW_THEN_INLINE,
)
true_noisy_program.append([cirq.CNOT(qubits[1], qubits[2])])
true_noisy_program.append(
[
cirq.DepolarizingChannel(0.01).on(q).with_tags(ops.VirtualTag())
for q in qubits
],
strategy=cirq.InsertStrategy.NEW_THEN_INLINE,
)
true_noisy_program.append([
cirq.BitFlipChannel(0.05).on(q).with_tags(ops.VirtualTag())
for q in qubits
])
true_noisy_program.append([
cirq.measure(qubits[0], key='q0'),
cirq.measure(qubits[1], key='q1'),
cirq.measure(qubits[2], key='q2'),
])
assert_equivalent_op_tree(true_noisy_program, noisy_circuit)
def test_readout_noise_no_prepend():
noise_model = ccn.ReadoutNoiseModel(bitflip_prob=0.005, prepend=False)
qubits = cirq.LineQubit.range(2)
moment = cirq.Moment([cirq.measure(*qubits, key="meas")])
noisy_mom = noise_model.noisy_moment(moment, system_qubits=qubits)
assert len(noisy_mom) == 2
assert noisy_mom[0] == moment
for g in noisy_mom[1]:
assert isinstance(g.gate, cirq.BitFlipChannel)