LightCone
class qiskit.transpiler.passes.LightCone(*args, **kwargs)
Bases: TransformationPass
Remove the gates that do not affect the outcome of a measurement on a circuit.
Pass for computing the light-cone of an observable or measurement. The Pass can handle either an observable one would like to measure or a measurement on a set of qubits.
Parameters
- bit_terms – If
Nonethe light-cone will be computed for the set of measurements in the circuit. If a string is specified, the light-cone will correspond to the reduced circuit with the same expectation value for the observable. - indices – list of non-trivial indices corresponding to the observable in
bit_terms.
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)
Execute optimization task for input Qiskit IR.
Parameters
- passmanager_ir (Any) – Qiskit IR to optimize.
- state (PassManagerState) – State associated with workflow execution by the pass manager itself.
- callback (Callable | None) – A callback function which is caller per execution of optimization task.
Returns
Optimized Qiskit IR and state of the workflow.
Return type
tuple[Any, qiskit.passmanager.compilation_status.PassManagerState]
name
run
run(dag)
Run the LightCone pass on dag.
Parameters
dag (DAGCircuit) – The DAG to reduce.
Returns
The DAG reduced to the light-cone of the observable.
Return type
update_status
update_status(state, run_state)
Update workflow status.
Parameters
- state (PassManagerState) – Pass manager state to update.
- run_state (RunState) – Completion status of current task.
Returns
Updated pass manager state.
Return type