BasicSwap

class qiskit.transpiler.passes.BasicSwap(*args, **kwargs)[source]

Bases: TransformationPass

Map (with minimum effort) a DAGCircuit onto a coupling_map adding swap gates.

The basic mapper is a minimum effort to insert swap gates to map the DAG onto a coupling map. When a cx is not in the coupling map possibilities, it inserts one or more swaps in front to make it compatible.

BasicSwap initializer.

Parameters:

  • coupling_map (Union[CouplingMap, Target]) – Directed graph represented a coupling map.

  • fake_run (bool) – if true, it will only pretend to do routing, i.e., no swap is effectively added.

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(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()

Name of the pass.

Return type:

str

run(dag)[source]

Run the BasicSwap pass on dag.

Parameters:

dag (DAGCircuit) – DAG to map.

Returns:

A mapped DAG.

Return type:

DAGCircuit

Raises:

  • TranspilerError – if the coupling map or the layout are not

  • compatible with the DAG, or if the coupling_map=None. –

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