def test_apply_noise_to_moments_initialization_2QubitNoise_2(
circuit_2qubit, noise_2qubit, noise_1qubit, noise_1qubit_2
):
circ = apply_noise_to_moments(
circuit_2qubit,
[noise_1qubit, noise_2qubit, noise_1qubit_2],
target_qubits=QubitSet([0, 1]),
position="initialization",
)
expected = (
Circuit()
.add_instruction(Instruction(noise_1qubit, 0))
.add_instruction(Instruction(noise_1qubit, 1))
.add_instruction(Instruction(noise_2qubit, [0, 1]))
.add_instruction(Instruction(noise_1qubit_2, 0))
.add_instruction(Instruction(noise_1qubit_2, 1))
.add_instruction(Instruction(Gate.X(), 0))
.add_instruction(Instruction(Gate.Y(), 1))
.add_instruction(Instruction(Gate.X(), 0))
.add_instruction(Instruction(Gate.X(), 1))
.add_instruction(Instruction(Gate.CNot(), [0, 1]))
)
assert circ == expected
def test_apply_noise_to_moments_readout_1QubitNoise_2(circuit_2qubit,
noise_1qubit):
circ = apply_noise_to_moments(
circuit_2qubit,
[noise_1qubit],
target_qubits=QubitSet(1),
position="readout",
)
expected = (Circuit().add_instruction(Instruction(
Gate.X(),
0)).add_instruction(Instruction(Gate.Y(), 1)).add_instruction(
Instruction(Gate.X(), 0)).add_instruction(Instruction(
Gate.X(), 1)).add_instruction(Instruction(
Gate.CNot(),
[0, 1])).add_instruction(Instruction(noise_1qubit, 1)))
assert circ == expected
def apply_readout_noise(
self,
noise: Union[Type[Noise], Iterable[Type[Noise]]],
target_qubits: Optional[QubitSetInput] = None,
) -> Circuit:
"""Apply `noise` right before measurement in every qubit (default) or target_qubits`.
Only when `target_qubits` is given can the noise be applied to an empty circuit.
When `noise.qubit_count` > 1, the number of qubits in target_qubits must be equal
to `noise.qubit_count`.
Args:
noise (Union[Type[Noise], Iterable[Type[Noise]]]): Noise channel(s) to be applied
to the circuit.
target_qubits (Union[QubitSetInput, optional]): Index or indices of qubit(s).
Default=None.
Returns:
Circuit: self
Raises:
TypeError:
If `noise` is not Noise type.
If `target_qubits` has non-integers.
IndexError:
If applying noise to an empty circuit.
ValueError:
If `target_qubits` has negative integers.
If `noise.qubit_count` > 1 and the number of qubits in target_qubits is
not the same as `noise.qubit_count`.
Examples:
>>> circ = Circuit().x(0).y(1).z(0).x(1).cnot(0,1)
>>> print(circ)
>>> noise = Noise.Depolarizing(probability=0.1)
>>> circ = Circuit().x(0).y(1).z(0).x(1).cnot(0,1)
>>> print(circ.apply_initialization_noise(noise))
>>> circ = Circuit().x(0).y(1).z(0).x(1).cnot(0,1)
>>> print(circ.apply_initialization_noise(noise, target_qubits = 1))
>>> circ = Circuit()
>>> print(circ.apply_initialization_noise(noise, target_qubits = [0, 1]))
"""
if (len(self.qubits) == 0) and (target_qubits is None):
raise IndexError(
"target_qubits must be provided in order to apply the readout noise \
to an empty circuit.")
if target_qubits is None:
target_qubits = self.qubits
else:
if not isinstance(target_qubits, list):
target_qubits = [target_qubits]
if not all(isinstance(q, int) for q in target_qubits):
raise TypeError("target_qubits must be integer(s)")
if not all(q >= 0 for q in target_qubits):
raise ValueError(
"target_qubits must contain only non-negative integers.")
target_qubits = QubitSet(target_qubits)
# make noise a list
noise = wrap_with_list(noise)
for noise_channel in noise:
if not isinstance(noise_channel, Noise):
raise TypeError("Noise must be an instance of the Noise class")
if noise_channel.qubit_count > 1 and noise_channel.qubit_count != len(
target_qubits):
raise ValueError(
"target_qubits needs to be provided for this multi-qubit noise channel, and \
the number of qubits in target_qubits must be the same as defined by the multi-qubit noise channel."
)
return apply_noise_to_moments(self, noise, target_qubits, "readout")