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PadDelay

PadDelay(durations, fill_very_end=True, schedule_idle_qubits=False)GitHub(opens in a new tab)

Padding idle time with Delay instructions.

Consecutive delays will be merged in the output of this pass.

The ASAP-scheduled circuit output may become

     ┌────────────────┐
q_0:Delay(160[dt]) ├──■──
     └─────┬───┬──────┘┌─┴─┐
q_1: ──────┤ X ├───────┤ X ├
           └───┘       └───┘

Note that the additional idle time of 60dt on the q_0 wire coming from the duration difference between Delay of 100dt (q_0) and XGate of 160 dt (q_1) is absorbed in the delay instruction on the q_0 wire, i.e. in total 160 dt.

See BlockBasePadder pass for details.

Create new padding delay pass.

Parameters

  • durations (InstructionDurations) – Durations of instructions to be used in scheduling.
  • fill_very_end (bool) – Set True to fill the end of circuit with delay.
  • schedule_idle_qubits (bool) – Set to true if you’d like a delay inserted on idle qubits. This is useful for timeline visualizations, but may cause issues for execution on large backends.

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

__call__

__call__(circuit, property_set=None)

Runs the pass on circuit.

Parameters

  • circuit (QuantumCircuit) – The dag on which the pass is run.
  • property_set (PropertySet | dict | None) – Input/output property set. An analysis pass might change the property set in-place.

Return type

QuantumCircuit

Returns

If on transformation pass, the resulting QuantumCircuit. If analysis pass, the input circuit.

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 (Optional[Callable]) – A callback function which is caller per execution of optimization task.

Return type

tuple[Any, PassManagerState]

Returns

Optimized Qiskit IR and state of the workflow.

name

name()

Name of the pass.

Return type

str

run

run(dag)

Run the padding pass on dag.

Parameters

dag (DAGCircuit) – DAG to be checked.

Returns

DAG with idle time filled with instructions.

Return type

DAGCircuit

Raises

TranspilerError – When a particular node is not scheduled, likely some transform pass is inserted before this node is called.

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.

Return type

PassManagerState

Returns

Updated pass manager state.

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