def pad_with_delays(qubits: List[int], until, unit) -> None:
"""Pad idle time-slots in ``qubits`` with delays in ``unit`` until ``until``."""
for q in qubits:
if qubit_stop_times[q] < until:
idle_duration = until - qubit_stop_times[q]
new_dag.apply_operation_back(Delay(idle_duration, unit),
[q])
def pad_with_delays(qubits: List[int], until, unit) -> None:
"""Pad idle time-slots in ``qubits`` with delays in ``unit`` until ``until``."""
for q in qubits:
if qubit_time_available[q] < until:
idle_duration = until - qubit_time_available[q]
new_dag.apply_operation_front(Delay(idle_duration, unit),
[q], [])
def _pad(
self,
dag: DAGCircuit,
qubit: Qubit,
time_interval: int,
next_node: DAGNode,
prev_node: DAGNode,
):
if not self.fill_very_end and isinstance(next_node, DAGOutNode):
return
dag.apply_operation_back(Delay(time_interval, dag.unit), [qubit])
def _pad(
self,
dag: DAGCircuit,
qubit: Qubit,
t_start: int,
t_end: int,
next_node: DAGNode,
prev_node: DAGNode,
):
if not self.fill_very_end and isinstance(next_node, DAGOutNode):
return
time_interval = t_end - t_start
self._apply_scheduled_op(dag, t_start, Delay(time_interval, dag.unit), qubit)
def _pad(
self,
dag: DAGCircuit,
qubit: Qubit,
t_start: int,
t_end: int,
next_node: DAGNode,
prev_node: DAGNode,
):
# This routine takes care of the pulse alignment constraint for the DD sequence.
# Note that the alignment constraint acts on the t0 of the DAGOpNode.
# Now this constrained scheduling problem is simplified to the problem of
# finding a delay amount which is a multiple of the constraint value by assuming
# that the duration of every DAGOpNode is also a multiple of the constraint value.
#
# For example, given the constraint value of 16 and XY4 with 160 dt gates.
# Here we assume current interval is 992 dt.
#
# relative spacing := [0.125, 0.25, 0.25, 0.25, 0.125]
# slack = 992 dt - 4 x 160 dt = 352 dt
#
# unconstraind sequence: 44dt-X1-88dt-Y2-88dt-X3-88dt-Y4-44dt
# constraind sequence : 32dt-X1-80dt-Y2-80dt-X3-80dt-Y4-32dt + extra slack 48 dt
#
# Now we evenly split extra slack into start and end of the sequence.
# The distributed slack should be multiple of 16.
# Start = +16, End += 32
#
# final sequence : 48dt-X1-80dt-Y2-80dt-X3-80dt-Y4-64dt / in total 992 dt
#
# Now we verify t0 of every node starts from multiple of 16 dt.
#
# X1: 48 dt (3 x 16 dt)
# Y2: 48 dt + 160 dt + 80 dt = 288 dt (18 x 16 dt)
# Y3: 288 dt + 160 dt + 80 dt = 528 dt (33 x 16 dt)
# Y4: 368 dt + 160 dt + 80 dt = 768 dt (48 x 16 dt)
#
# As you can see, constraints on t0 are all satified without explicit scheduling.
time_interval = t_end - t_start
if self._qubits and dag.qubits.index(qubit) not in self._qubits:
# Target physical qubit is not the target of this DD sequence.
self._apply_scheduled_op(dag, t_start,
Delay(time_interval, dag.unit), qubit)
return
if self._skip_reset_qubits and (isinstance(prev_node, DAGInNode)
or isinstance(prev_node.op, Reset)):
# Previous node is the start edge or reset, i.e. qubit is ground state.
self._apply_scheduled_op(dag, t_start,
Delay(time_interval, dag.unit), qubit)
return
slack = time_interval - np.sum(self._dd_sequence_lengths[qubit])
sequence_gphase = self._sequence_phase
if slack <= 0:
# Interval too short.
self._apply_scheduled_op(dag, t_start,
Delay(time_interval, dag.unit), qubit)
return
if len(self._dd_sequence) == 1:
# Special case of using a single gate for DD
u_inv = self._dd_sequence[0].inverse().to_matrix()
theta, phi, lam, phase = OneQubitEulerDecomposer(
).angles_and_phase(u_inv)
if isinstance(next_node, DAGOpNode) and isinstance(
next_node.op, (UGate, U3Gate)):
# Absorb the inverse into the successor (from left in circuit)
theta_r, phi_r, lam_r = next_node.op.params
next_node.op.params = Optimize1qGates.compose_u3(
theta_r, phi_r, lam_r, theta, phi, lam)
sequence_gphase += phase
elif isinstance(prev_node, DAGOpNode) and isinstance(
prev_node.op, (UGate, U3Gate)):
# Absorb the inverse into the predecessor (from right in circuit)
theta_l, phi_l, lam_l = prev_node.op.params
prev_node.op.params = Optimize1qGates.compose_u3(
theta, phi, lam, theta_l, phi_l, lam_l)
sequence_gphase += phase
else:
# Don't do anything if there's no single-qubit gate to absorb the inverse
self._apply_scheduled_op(dag, t_start,
Delay(time_interval, dag.unit), qubit)
return
def _constrained_length(values):
return self._alignment * np.floor(values / self._alignment)
# (1) Compute DD intervals satisfying the constraint
taus = _constrained_length(slack * np.asarray(self._spacing))
extra_slack = slack - np.sum(taus)
# (2) Distribute extra slack
if self._extra_slack_distribution == "middle":
mid_ind = int((len(taus) - 1) / 2)
to_middle = _constrained_length(extra_slack)
taus[mid_ind] += to_middle
if extra_slack - to_middle:
# If to_middle is not a multiple value of the pulse alignment,
# it is truncated to the nearlest multiple value and
# the rest of slack is added to the end.
taus[-1] += extra_slack - to_middle
elif self._extra_slack_distribution == "edges":
to_begin_edge = _constrained_length(extra_slack / 2)
taus[0] += to_begin_edge
taus[-1] += extra_slack - to_begin_edge
else:
raise TranspilerError(
f"Option extra_slack_distribution = {self._extra_slack_distribution} is invalid."
)
# (3) Construct DD sequence with delays
num_elements = max(len(self._dd_sequence), len(taus))
idle_after = t_start
for dd_ind in range(num_elements):
if dd_ind < len(taus):
tau = taus[dd_ind]
if tau > 0:
self._apply_scheduled_op(dag, idle_after,
Delay(tau, dag.unit), qubit)
idle_after += tau
if dd_ind < len(self._dd_sequence):
gate = self._dd_sequence[dd_ind]
gate_length = self._dd_sequence_lengths[qubit][dd_ind]
self._apply_scheduled_op(dag, idle_after, gate, qubit)
idle_after += gate_length
dag.global_phase = self._mod_2pi(dag.global_phase + sequence_gphase)
def run(self, dag):
"""Run the DynamicalDecoupling pass on dag.
Args:
dag (DAGCircuit): a scheduled DAG.
Returns:
DAGCircuit: equivalent circuit with delays interrupted by DD,
where possible.
Raises:
TranspilerError: if the circuit is not mapped on physical qubits.
"""
if len(dag.qregs) != 1 or dag.qregs.get("q", None) is None:
raise TranspilerError("DD runs on physical circuits only.")
if dag.duration is None:
raise TranspilerError("DD runs after circuit is scheduled.")
num_pulses = len(self._dd_sequence)
sequence_gphase = 0
if num_pulses != 1:
if num_pulses % 2 != 0:
raise TranspilerError(
"DD sequence must contain an even number of gates (or 1).")
noop = np.eye(2)
for gate in self._dd_sequence:
noop = noop.dot(gate.to_matrix())
if not matrix_equal(noop, IGate().to_matrix(), ignore_phase=True):
raise TranspilerError(
"The DD sequence does not make an identity operation.")
sequence_gphase = np.angle(noop[0][0])
if self._qubits is None:
self._qubits = set(range(dag.num_qubits()))
else:
self._qubits = set(self._qubits)
if self._spacing:
if sum(self._spacing) != 1 or any(a < 0 for a in self._spacing):
raise TranspilerError(
"The spacings must be given in terms of fractions "
"of the slack period and sum to 1.")
else: # default to balanced spacing
mid = 1 / num_pulses
end = mid / 2
self._spacing = [end] + [mid] * (num_pulses - 1) + [end]
new_dag = dag._copy_circuit_metadata()
qubit_index_map = {
qubit: index
for index, qubit in enumerate(new_dag.qubits)
}
index_sequence_duration_map = {}
for qubit in new_dag.qubits:
physical_qubit = qubit_index_map[qubit]
dd_sequence_duration = 0
for gate in self._dd_sequence:
gate.duration = self._durations.get(gate, physical_qubit)
dd_sequence_duration += gate.duration
index_sequence_duration_map[physical_qubit] = dd_sequence_duration
for nd in dag.topological_op_nodes():
if not isinstance(nd.op, Delay):
new_dag.apply_operation_back(nd.op, nd.qargs, nd.cargs)
continue
dag_qubit = nd.qargs[0]
physical_qubit = qubit_index_map[dag_qubit]
if physical_qubit not in self._qubits: # skip unwanted qubits
new_dag.apply_operation_back(nd.op, nd.qargs, nd.cargs)
continue
pred = next(dag.predecessors(nd))
succ = next(dag.successors(nd))
if self._skip_reset_qubits: # discount initial delays
if pred.type == "in" or isinstance(pred.op, Reset):
new_dag.apply_operation_back(nd.op, nd.qargs, nd.cargs)
continue
dd_sequence_duration = index_sequence_duration_map[physical_qubit]
slack = nd.op.duration - dd_sequence_duration
if slack <= 0: # dd doesn't fit
new_dag.apply_operation_back(nd.op, nd.qargs, nd.cargs)
continue
if num_pulses == 1: # special case of using a single gate for DD
u_inv = self._dd_sequence[0].inverse().to_matrix()
theta, phi, lam, phase = OneQubitEulerDecomposer(
).angles_and_phase(u_inv)
# absorb the inverse into the successor (from left in circuit)
if succ.type == "op" and isinstance(succ.op, (UGate, U3Gate)):
theta_r, phi_r, lam_r = succ.op.params
succ.op.params = Optimize1qGates.compose_u3(
theta_r, phi_r, lam_r, theta, phi, lam)
sequence_gphase += phase
# absorb the inverse into the predecessor (from right in circuit)
elif pred.type == "op" and isinstance(pred.op,
(UGate, U3Gate)):
theta_l, phi_l, lam_l = pred.op.params
pred.op.params = Optimize1qGates.compose_u3(
theta, phi, lam, theta_l, phi_l, lam_l)
sequence_gphase += phase
# don't do anything if there's no single-qubit gate to absorb the inverse
else:
new_dag.apply_operation_back(nd.op, nd.qargs, nd.cargs)
continue
# insert the actual DD sequence
taus = [int(slack * a) for a in self._spacing]
unused_slack = slack - sum(
taus) # unused, due to rounding to int multiples of dt
middle_index = int(
(len(taus) - 1) / 2) # arbitrary: redistribute to middle
taus[
middle_index] += unused_slack # now we add up to original delay duration
for tau, gate in itertools.zip_longest(taus, self._dd_sequence):
if tau > 0:
new_dag.apply_operation_back(Delay(tau), [dag_qubit])
if gate is not None:
new_dag.apply_operation_back(gate, [dag_qubit])
new_dag.global_phase = _mod_2pi(new_dag.global_phase +
sequence_gphase)
return new_dag
def convert_to_target(conf_dict: dict,
props_dict: dict = None,
defs_dict: dict = None) -> Target:
"""Uses configuration, properties and pulse defaults dicts
to construct and return Target class.
"""
name_mapping = {
"id": IGate(),
"sx": SXGate(),
"x": XGate(),
"cx": CXGate(),
"rz": RZGate(Parameter("λ")),
"reset": Reset(),
}
custom_gates = {}
qubit_props = None
if props_dict:
qubit_props = qubit_props_from_props(props_dict)
target = Target(qubit_properties=qubit_props)
# Parse from properties if it exsits
if props_dict is not None:
# Parse instructions
gates = {}
for gate in props_dict["gates"]:
name = gate["gate"]
if name in name_mapping:
if name not in gates:
gates[name] = {}
elif name not in custom_gates:
custom_gate = Gate(name, len(gate["qubits"]), [])
custom_gates[name] = custom_gate
gates[name] = {}
qubits = tuple(gate["qubits"])
gate_props = {}
for param in gate["parameters"]:
if param["name"] == "gate_error":
gate_props["error"] = param["value"]
if param["name"] == "gate_length":
gate_props["duration"] = apply_prefix(
param["value"], param["unit"])
gates[name][qubits] = InstructionProperties(**gate_props)
for gate, props in gates.items():
if gate in name_mapping:
inst = name_mapping.get(gate)
else:
inst = custom_gates[gate]
target.add_instruction(inst, props)
# Create measurement instructions:
measure_props = {}
count = 0
for qubit in props_dict["qubits"]:
qubit_prop = {}
for prop in qubit:
if prop["name"] == "readout_length":
qubit_prop["duration"] = apply_prefix(
prop["value"], prop["unit"])
if prop["name"] == "readout_error":
qubit_prop["error"] = prop["value"]
measure_props[(count, )] = InstructionProperties(**qubit_prop)
count += 1
target.add_instruction(Measure(), measure_props)
# Parse from configuration because properties doesn't exist
else:
for gate in conf_dict["gates"]:
name = gate["name"]
gate_props = {tuple(x): None for x in gate["coupling_map"]}
if name in name_mapping:
target.add_instruction(name_mapping[name], gate_props)
else:
custom_gate = Gate(name, len(gate["coupling_map"][0]), [])
target.add_instruction(custom_gate, gate_props)
measure_props = {(n, ): None for n in range(conf_dict["n_qubits"])}
target.add_instruction(Measure(), measure_props)
# parse global configuration properties
dt = conf_dict.get("dt")
if dt:
target.dt = dt * 1e-9
if "timing_constraints" in conf_dict:
target.granularity = conf_dict["timing_constraints"].get("granularity")
target.min_length = conf_dict["timing_constraints"].get("min_length")
target.pulse_alignment = conf_dict["timing_constraints"].get(
"pulse_alignment")
target.aquire_alignment = conf_dict["timing_constraints"].get(
"acquire_alignment")
# If pulse defaults exists use that as the source of truth
if defs_dict is not None:
# TODO remove the usage of PulseDefaults as it will be deprecated in the future
pulse_defs = PulseDefaults.from_dict(defs_dict)
inst_map = pulse_defs.instruction_schedule_map
for inst in inst_map.instructions:
for qarg in inst_map.qubits_with_instruction(inst):
sched = inst_map.get(inst, qarg)
if inst in target:
try:
qarg = tuple(qarg)
except TypeError:
qarg = (qarg, )
if inst == "measure":
for qubit in qarg:
target[inst][(qubit, )].calibration = sched
else:
target[inst][qarg].calibration = sched
target.add_instruction(Delay(Parameter("t")),
{(bit, ): None
for bit in range(target.num_qubits)})
return target
def convert_to_target(
configuration: BackendConfiguration,
properties: BackendProperties = None,
defaults: PulseDefaults = None,
) -> Target:
"""Uses configuration, properties and pulse defaults
to construct and return Target class.
"""
name_mapping = {
"id": IGate(),
"sx": SXGate(),
"x": XGate(),
"cx": CXGate(),
"rz": RZGate(Parameter("λ")),
"reset": Reset(),
}
custom_gates = {}
target = None
# Parse from properties if it exsits
if properties is not None:
qubit_properties = qubit_props_list_from_props(properties=properties)
target = Target(
num_qubits=configuration.n_qubits, qubit_properties=qubit_properties
)
# Parse instructions
gates: Dict[str, Any] = {}
for gate in properties.gates:
name = gate.gate
if name in name_mapping:
if name not in gates:
gates[name] = {}
elif name not in custom_gates:
custom_gate = Gate(name, len(gate.qubits), [])
custom_gates[name] = custom_gate
gates[name] = {}
qubits = tuple(gate.qubits)
gate_props = {}
for param in gate.parameters:
if param.name == "gate_error":
gate_props["error"] = param.value
if param.name == "gate_length":
gate_props["duration"] = apply_prefix(param.value, param.unit)
gates[name][qubits] = InstructionProperties(**gate_props)
for gate, props in gates.items():
if gate in name_mapping:
inst = name_mapping.get(gate)
else:
inst = custom_gates[gate]
target.add_instruction(inst, props)
# Create measurement instructions:
measure_props = {}
for qubit, _ in enumerate(properties.qubits):
measure_props[(qubit,)] = InstructionProperties(
duration=properties.readout_length(qubit),
error=properties.readout_error(qubit),
)
target.add_instruction(Measure(), measure_props)
# Parse from configuration because properties doesn't exist
else:
target = Target(num_qubits=configuration.n_qubits)
for gate in configuration.gates:
name = gate.name
gate_props = (
{tuple(x): None for x in gate.coupling_map} # type: ignore[misc]
if hasattr(gate, "coupling_map")
else {None: None}
)
gate_len = len(gate.coupling_map[0]) if hasattr(gate, "coupling_map") else 0
if name in name_mapping:
target.add_instruction(name_mapping[name], gate_props)
else:
custom_gate = Gate(name, gate_len, [])
target.add_instruction(custom_gate, gate_props)
target.add_instruction(Measure())
# parse global configuration properties
if hasattr(configuration, "dt"):
target.dt = configuration.dt
if hasattr(configuration, "timing_constraints"):
target.granularity = configuration.timing_constraints.get("granularity")
target.min_length = configuration.timing_constraints.get("min_length")
target.pulse_alignment = configuration.timing_constraints.get("pulse_alignment")
target.aquire_alignment = configuration.timing_constraints.get(
"acquire_alignment"
)
# If a pulse defaults exists use that as the source of truth
if defaults is not None:
inst_map = defaults.instruction_schedule_map
for inst in inst_map.instructions:
for qarg in inst_map.qubits_with_instruction(inst):
sched = inst_map.get(inst, qarg)
if inst in target:
try:
qarg = tuple(qarg)
except TypeError:
qarg = (qarg,)
if inst == "measure":
for qubit in qarg:
target[inst][(qubit,)].calibration = sched
else:
target[inst][qarg].calibration = sched
if "delay" not in target:
target.add_instruction(
Delay(Parameter("t")), {(bit,): None for bit in range(target.num_qubits)}
)
return target