Padding idle time with Delay instructions.
Consecutive delays will be merged in the output of this pass.
durations = InstructionDurations([("x", None, 160), ("cx", None, 800)]) qc = QuantumCircuit(2) qc.delay(100, 0) qc.x(1) qc.cx(0, 1)
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 (
XGate of 160 dt (
q_1) is absorbed in the delay instruction on the
q_0 wire, i.e. in total 160 dt.
BasePadding pass for details.
Create new padding delay pass.
- fill_very_end – Set
Trueto fill the end of circuit with delay.
- target – The
Targetrepresenting the target backend. If it supplied and it does not support delay instruction on a qubit, padding passes do not pad any idle time of the qubit.
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.
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).
execute(passmanager_ir, state, callback=None)
Execute optimization task for input Qiskit IR.
- passmanager_ir (Any (opens in a new tab)) – Qiskit IR to optimize.
- state (PassManagerState) – State associated with workflow execution by the pass manager itself.
- callback (Callable (opens in a new tab) | None) – A callback function which is caller per execution of optimization task.
Optimized Qiskit IR and state of the workflow.
Name of the pass.
Run the padding pass on
dag (DAGCircuit) – DAG to be checked.
DAG with idle time filled with instructions.
TranspilerError – When a particular node is not scheduled, likely some transform pass is inserted before this node is called.
Update workflow status.
- state (PassManagerState) – Pass manager state to update.
- run_state (RunState) – Completion status of current task.
Updated pass manager state.