def __init__(self, inst_map: InstructionScheduleMap,
meas_map: List[List[int]]):
"""
Container for information needed to schedule a QuantumCircuit into a pulse Schedule.
Args:
inst_map: The schedule definition of all gates supported on a backend.
meas_map: A list of groups of qubits which have to be measured together.
"""
self.inst_map = inst_map
self.meas_map = format_meas_map(meas_map)
def measure(qubits: List[int],
backend=None,
inst_map: Optional[InstructionScheduleMap] = None,
meas_map: Optional[Union[List[List[int]], Dict[int,
List[int]]]] = None,
qubit_mem_slots: Optional[Dict[int, int]] = None,
measure_name: str = 'measure') -> Schedule:
"""Return a schedule which measures the requested qubits according to the given
instruction mapping and measure map, or by using the defaults provided by the backend.
By default, the measurement results for each qubit are trivially mapped to the qubit
index. This behavior is overridden by qubit_mem_slots. For instance, to measure
qubit 0 into MemorySlot(1), qubit_mem_slots can be provided as {0: 1}.
Args:
qubits: List of qubits to be measured.
backend (Union[Backend, BaseBackend]): A backend instance, which contains
hardware-specific data required for scheduling.
inst_map: Mapping of circuit operations to pulse schedules. If None, defaults to the
``instruction_schedule_map`` of ``backend``.
meas_map: List of sets of qubits that must be measured together. If None, defaults to
the ``meas_map`` of ``backend``.
qubit_mem_slots: Mapping of measured qubit index to classical bit index.
measure_name: Name of the measurement schedule.
Returns:
A measurement schedule corresponding to the inputs provided.
Raises:
PulseError: If both ``inst_map`` or ``meas_map``, and ``backend`` is None.
"""
schedule = Schedule(
name="Default measurement schedule for qubits {}".format(qubits))
try:
inst_map = inst_map or backend.defaults().instruction_schedule_map
meas_map = meas_map or backend.configuration().meas_map
except AttributeError:
raise exceptions.PulseError(
'inst_map or meas_map, and backend cannot be None simultaneously')
if isinstance(meas_map, list):
meas_map = utils.format_meas_map(meas_map)
measure_groups = set()
for qubit in qubits:
measure_groups.add(tuple(meas_map[qubit]))
for measure_group_qubits in measure_groups:
if qubit_mem_slots is not None:
unused_mem_slots = set(measure_group_qubits) - set(
qubit_mem_slots.values())
try:
default_sched = inst_map.get(measure_name, measure_group_qubits)
except exceptions.PulseError:
raise exceptions.PulseError(
"We could not find a default measurement schedule called '{}'. "
"Please provide another name using the 'measure_name' keyword "
"argument. For assistance, the instructions which are defined are: "
"{}".format(measure_name, inst_map.instructions))
for time, inst in default_sched.instructions:
if qubit_mem_slots and isinstance(inst, instructions.Acquire):
if inst.channel.index in qubit_mem_slots:
mem_slot = channels.MemorySlot(
qubit_mem_slots[inst.channel.index])
else:
mem_slot = channels.MemorySlot(unused_mem_slots.pop())
schedule = schedule.insert(
time,
instructions.Acquire(inst.duration,
inst.channel,
mem_slot=mem_slot))
elif qubit_mem_slots is None and isinstance(
inst, instructions.Acquire):
schedule = schedule.insert(time, inst)
# Measurement pulses should only be added if its qubit was measured by the user
elif inst.channels[0].index in qubits:
schedule = schedule.insert(time, inst)
return schedule