# This code is part of Qiskit.
#
# (C) Copyright IBM 2017, 2018.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.
"""Check if a DAG circuit is already mapped to a coupling map."""
from qiskit.transpiler.basepasses import AnalysisPass
from qiskit.transpiler.target import Target
from qiskit.circuit.controlflow import ControlFlowOp
from qiskit.converters import circuit_to_dag
[documentos]class CheckMap(AnalysisPass):
"""Check if a DAG circuit is already mapped to a coupling map.
Check if a DAGCircuit is mapped to `coupling_map` by checking that all
2-qubit interactions are laid out to be on adjacent qubits in the global coupling
map of the device, setting the property set field (either specified with ``property_set_field``
or the default ``is_swap_mapped``) to ``True`` or ``False`` accordingly. Note this does not
validate directionality of the connectivity between qubits. If you need to check gates are
implemented in a native direction for a target use the :class:`~.CheckGateDirection` pass
instead.
"""
def __init__(self, coupling_map, property_set_field=None):
"""CheckMap initializer.
Args:
coupling_map (Union[CouplingMap, Target]): Directed graph representing a coupling map.
property_set_field (str): An optional string to specify the property set field to
store the result of the check. If not default the result is stored in
``"is_swap_mapped"``.
"""
super().__init__()
if property_set_field is None:
self.property_set_field = "is_swap_mapped"
else:
self.property_set_field = property_set_field
if isinstance(coupling_map, Target):
cmap = coupling_map.build_coupling_map()
else:
cmap = coupling_map
if cmap is None:
self.qargs = None
else:
self.qargs = set()
for edge in cmap.get_edges():
self.qargs.add(edge)
self.qargs.add((edge[1], edge[0]))
[documentos] def run(self, dag):
"""Run the CheckMap pass on `dag`.
If `dag` is mapped to `coupling_map`, the property
`is_swap_mapped` is set to True (or to False otherwise).
Args:
dag (DAGCircuit): DAG to map.
"""
if not self.qargs:
self.property_set[self.property_set_field] = True
return
wire_map = {bit: index for index, bit in enumerate(dag.qubits)}
self.property_set[self.property_set_field] = self._recurse(dag, wire_map)
def _recurse(self, dag, wire_map) -> bool:
for node in dag.op_nodes(include_directives=False):
if isinstance(node.op, ControlFlowOp):
for block in node.op.blocks:
inner_wire_map = {
inner: wire_map[outer] for inner, outer in zip(block.qubits, node.qargs)
}
if not self._recurse(circuit_to_dag(block), inner_wire_map):
return False
elif (
len(node.qargs) == 2
and not dag.has_calibration_for(node)
and (wire_map[node.qargs[0]], wire_map[node.qargs[1]]) not in self.qargs
):
self.property_set["check_map_msg"] = "{}({}, {}) failed".format(
node.name,
wire_map[node.qargs[0]],
wire_map[node.qargs[1]],
)
return False
return True