CommutativeCancellation

class qiskit.transpiler.passes.CommutativeCancellation(*args, **kwargs)

Bases: TransformationPass

Cancel the redundant (self-adjoint) gates through commutation relations.

Pass for cancelling self-inverse gates/rotations. The cancellation utilizes the commutation relations in the circuit. Gates considered include:

H, X, Y, Z, CX, CY, CZ

This pass is multithreaded and will potentially launch a thread pool with threads equal to the number of CPUs by default. You can tune the number of threads with the RAYON_NUM_THREADS environment variable. For example, setting RAYON_NUM_THREADS=4 would limit the thread pool to 4 threads.

CommutativeCancellation initializer.

Parameters

basis_gates (list[str]) – Basis gates to consider, e.g. ['u3', 'cx']. For the effects of this pass, the basis is the set intersection between the basis_gates parameter and the gates in the dag.
target (Target) – The Target representing the target backend, if both basis_gates and target are specified then this argument will take precedence and basis_gates will be ignored.
approximation_degree – The threshold used in the average gate fidelity computation to decide whether pairs of gates can be considered as canceling or commuting. A floating point value between 0 and 1, where 1.0 means no approximation (default).

Attributes

is_analysis_pass

Check if the pass is an analysis pass.

If the pass is an AnalysisPass, that means that the pass can analyze the DAG and write the results of that analysis in the property set. Modifications on the DAG are not allowed by this kind of pass.

is_transformation_pass

Check if the pass is a transformation pass.

If the pass is a TransformationPass, that means that the pass can manipulate the DAG, but cannot modify the property set (but it can be read).

Methods

execute

execute(passmanager_ir, state, callback=None)

GitHub

Execute optimization task for input Qiskit IR.

Parameters

passmanager_ir (DAGCircuit) – Qiskit IR to optimize.
state (DAGCircuit) – State associated with workflow execution by the pass manager itself.
callback (Callable[[Task, DAGCircuit, PropertySet, float, int], None] | None) – A callback function which is called per execution of optimization task.