PadDelay

class PadDelay(*args, **kwargs)[source]

Bases: BlockBasePadder

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 – Durations of instructions to be used in scheduling.

  • fill_very_end – Set True to fill the end of circuit with delay.

  • schedule_idle_qubits – 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.

  • block_ordering_callable – A callable used to produce an ordering of the nodes to minimize the number of blocks needed. If not provided, block_order_op_nodes() will be used.

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__(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. If not given, the existing property_set attribute of the pass will be used (if set).

Returns:

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

Return type:

QuantumCircuit

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, PassManagerState]

name()

Name of the pass.

Return type:

str

run(dag)[source]

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(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:

PassManagerState