def test_moment_by_moment_schedule_empty_moment():
device = _TestDevice()
circuit = Circuit([
Moment(),
])
schedule = moment_by_moment_schedule(device, circuit)
assert len(schedule.scheduled_operations) == 0
def test_moment_by_moment_schedule_empty_moment_ignored():
device = _TestDevice()
qubits = device.qubits
circuit = Circuit(
[Moment([ops.H(qubits[0])]),
Moment([]),
Moment([ops.H(qubits[0])])])
schedule = moment_by_moment_schedule(device, circuit)
zero_ns = cirq.Timestamp()
twenty_ns = cirq.Timestamp(nanos=20)
assert set(schedule.scheduled_operations) == {
ScheduledOperation.op_at_on(ops.H(qubits[0]), zero_ns, device),
ScheduledOperation.op_at_on(ops.H(qubits[0]), twenty_ns, device),
}
def _generate_sample_2q_xeb_tasks(
zipped_circuits: List[_ZippedCircuit], cycle_depths: Sequence[int]
) -> List[_Sample2qXEBTask]:
"""Helper function used in `sample_2q_xeb_circuits` to prepare circuits in sampling tasks."""
tasks: List[_Sample2qXEBTask] = []
for cycle_depth in cycle_depths:
for zipped_circuit in zipped_circuits:
circuit_depth = cycle_depth * 2 + 1
assert circuit_depth <= len(zipped_circuit.wide_circuit)
# Slicing creates a copy, although this isn't documented
prepared_circuit = zipped_circuit.wide_circuit[:circuit_depth]
prepared_circuit += Moment(
ops.measure(*pair, key=str(pair_i))
for pair_i, pair in enumerate(zipped_circuit.pairs)
)
tasks.append(
_Sample2qXEBTask(
cycle_depth=cycle_depth,
layer_i=zipped_circuit.layer_i,
combination_i=zipped_circuit.combination_i,
prepared_circuit=prepared_circuit,
combination=zipped_circuit.combination,
)
)
return tasks
def test_moment_by_moment_schedule_device_validation_fails():
device = _TestDevice()
qubits = device.qubits
circuit = Circuit(
[Moment([ops.CZ(qubits[0], qubits[1]),
ops.CZ(qubits[2], qubits[3])])])
with pytest.raises(ValueError, match="Adjacent CZ"):
_ = moment_by_moment_schedule(device, circuit)
def test_moment_by_moment_schedule_max_duration():
device = _TestDevice()
qubits = device.qubits
circuit = Circuit([
Moment([ops.H(qubits[0]),
ops.CZ(qubits[1], qubits[2])]),
Moment([ops.H(qubits[0])])
])
schedule = moment_by_moment_schedule(device, circuit)
zero_ns = cirq.Timestamp()
fourty_ns = cirq.Timestamp(nanos=40)
assert set(schedule.scheduled_operations) == {
ScheduledOperation.op_at_on(ops.H(qubits[0]), zero_ns, device),
ScheduledOperation.op_at_on(ops.CZ(qubits[1], qubits[2]), zero_ns,
device),
ScheduledOperation.op_at_on(ops.H(qubits[0]), fourty_ns, device),
}
def test_moment_by_moment_schedule_two_moments():
device = _TestDevice()
qubits = device.qubits
circuit = Circuit([
Moment(ops.H(q) for q in qubits),
Moment((ops.CZ(qubits[i], qubits[i + 1]) for i in range(0, 9, 3)))
])
schedule = moment_by_moment_schedule(device, circuit)
zero_ns = cirq.Timestamp()
twenty_ns = cirq.Timestamp(nanos=20)
expected_one_qubit = set(
ScheduledOperation.op_at_on(ops.H(q), zero_ns, device) for q in qubits)
expected_two_qubit = set(
ScheduledOperation.op_at_on(ops.CZ(qubits[i], qubits[i + 1]),
twenty_ns, device) for i in range(0, 9, 3))
expected = expected_one_qubit.union(expected_two_qubit)
assert set(schedule.scheduled_operations) == expected
def random_circuit(
qubits: Union[Sequence[ops.QubitId], int],
n_moments: int,
op_density: float,
gate_domain: Optional[Dict[ops.Gate, int]] = None) -> Circuit:
"""Generates a random circuit.
Args:
qubits: the qubits that the circuit acts on. Because the qubits on
which an operation acts are chosen randomly, not all given qubits
may be acted upon.
n_moments: the number of moments in the generated circuit.
op_density: the expected proportion of qubits that are acted on in any
moment.
gate_domain: The set of gates to choose from, with a specified arity.
Raises:
ValueError:
* op_density is not in (0, 1).
* gate_domain is empty.
* qubits is an int less than 1 or an empty sequence.
Returns:
The randomly generated Circuit.
"""
if not 0 < op_density < 1:
raise ValueError('op_density must be in (0, 1).')
if gate_domain is None:
gate_domain = DEFAULT_GATE_DOMAIN
if not gate_domain:
raise ValueError('gate_domain must be non-empty')
max_arity = max(gate_domain.values())
if isinstance(qubits, int):
qubits = tuple(ops.NamedQubit(str(i)) for i in range(qubits))
n_qubits = len(qubits)
if n_qubits < 1:
raise ValueError('At least one qubit must be specified.')
moments = [] # type: List[Moment]
for _ in range(n_moments):
operations = []
free_qubits = set(q for q in qubits)
while len(free_qubits) >= max_arity:
gate, arity = choice(tuple(gate_domain.items()))
op_qubits = sample(free_qubits, arity)
free_qubits.difference_update(op_qubits)
if random() <= op_density:
operations.append(gate(*op_qubits))
moments.append(Moment(operations))
return Circuit(moments)
def test_moment_by_moment_schedule_moment_of_two_qubit_ops():
device = _TestDevice()
qubits = device.qubits
circuit = Circuit(
[Moment((ops.CZ(qubits[i], qubits[i + 1]) for i in range(0, 9, 3)))])
schedule = moment_by_moment_schedule(device, circuit)
zero_ns = cirq.Timestamp()
expected = set(
ScheduledOperation.op_at_on(ops.CZ(qubits[i], qubits[i + 1]), zero_ns,
device) for i in range(0, 9, 3))
assert set(schedule.scheduled_operations) == expected
def test_moment_by_moment_schedule_moment_of_single_qubit_ops():
device = _TestDevice()
qubits = device.qubits
circuit = Circuit([
Moment(ops.H(q) for q in qubits),
])
schedule = moment_by_moment_schedule(device, circuit)
zero_ns = cirq.Timestamp()
assert set(schedule.scheduled_operations) == {
ScheduledOperation.op_at_on(ops.H(q), zero_ns, device)
for q in qubits
}
def can_add_operation_into_moment(self, operation: ops.Operation,
moment: circuits.Moment) -> bool:
"""Determines if it's possible to add an operation into a moment.
An operation can be added if the moment with the operation added is valid.
Args:
operation: The operation being added.
moment: The moment being transformed.
Returns:
Whether or not the moment will validate after adding the operation.
Raises:
ValueError: If either of the given moment or operation is invalid
"""
if not super().can_add_operation_into_moment(operation, moment):
return False
try:
self.validate_moment(moment.with_operation(operation))
except:
return False
return True