Source code for circuit_knitting.utils.transpiler_passes
# This code is a Qiskit project.
# (C) Copyright IBM 2023.
# 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.
"""
Transpiler passes useful for circuit knitting.
.. currentmodule:: circuit_knitting.utils.transpiler_passes
.. autosummary::
:toctree: ../stubs/
RemoveFinalReset
ConsolidateResets
"""
from qiskit.circuit import Reset, Qubit
from qiskit.dagcircuit import DAGOpNode
from qiskit.transpiler.basepasses import TransformationPass
[docs]
class RemoveFinalReset(TransformationPass):
"""Remove reset when it is the final instruction on a qubit wire."""
def run(self, dag):
"""Run the RemoveFinalReset pass on ``dag``.
Args:
dag (DAGCircuit): the DAG to be optimized.
Returns:
DAGCircuit: the optimized DAG.
"""
for output_node in dag.output_map.values():
if isinstance(output_node.wire, Qubit):
pred = next(dag.predecessors(output_node))
if isinstance(pred, DAGOpNode) and isinstance(pred.op, Reset):
dag.remove_op_node(pred)
return dag
[docs]
class ConsolidateResets(TransformationPass):
"""Consolidate a run duplicate resets in to a single reset."""
def run(self, dag):
"""Run the ConsolidateResets pass on ``dag``.
Args:
dag (DAGCircuit): the DAG to be optimized.
Returns:
DAGCircuit: the optimized DAG.
"""
resets = dag.op_nodes(Reset)
for reset in resets:
successor = next(dag.successors(reset))
if isinstance(successor, DAGOpNode) and isinstance(successor.op, Reset):
dag.remove_op_node(reset)
return dag