---
title: Layout2qDistance (latest version)
description: API reference for qiskit.transpiler.passes.Layout2qDistance in the latest version of qiskit
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/qiskit.transpiler.passes.Layout2qDistance
---

# Layout2qDistance

*class* `qiskit.transpiler.passes.Layout2qDistance(*args, **kwargs)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.5/qiskit/transpiler/passes/layout/layout_2q_distance.py#L25-L77)

Bases: [`AnalysisPass`](/docs/api/qiskit/qiskit.transpiler.AnalysisPass "qiskit.transpiler.basepasses.AnalysisPass")

Evaluate how good the layout selection was.

Saves in `property_set['layout_score']` (or the property name in property\_name) the sum of distances for each circuit CX. The lower the number, the better the selection. Therefore, 0 is a perfect layout selection. No CX direction is considered.

Layout2qDistance initializer.

**Parameters**

- **coupling\_map** (*Union\[*[*CouplingMap*](/docs/api/qiskit/qiskit.transpiler.CouplingMap "qiskit.transpiler.CouplingMap")*,* [*Target*](/docs/api/qiskit/qiskit.transpiler.Target "qiskit.transpiler.Target")*]*) – Directed graph representing a coupling map.
- **property\_name** ([*str*](https://docs.python.org/3/library/stdtypes.html#str)) – The property name to save the score. Default: layout\_score

## 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)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.5/qiskit/passmanager/base_tasks.py#L76-L122)

Execute optimization task for input Qiskit IR.

**Parameters**

- **passmanager\_ir** (*IR*) – Qiskit IR to optimize.
- **state** ([*PassManagerState*](/docs/api/qiskit/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – State associated with workflow execution by the pass manager itself.
- **callback** ([*Callable*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Callable)*\[\[*[*Task*](/docs/api/qiskit/qiskit.passmanager.Task "qiskit.passmanager.base_tasks.Task")*, IR\_OUT,* [*PropertySet*](/docs/api/qiskit/qiskit.passmanager.PropertySet "qiskit.passmanager.compilation_status.PropertySet")*,* [*float*](https://docs.python.org/3/library/functions.html#float)*,* [*int*](https://docs.python.org/3/library/functions.html#int)*], None] | None*) – A callback function which is called per execution of optimization task.

**Returns**

Optimized Qiskit IR and state of the workflow.

**Return type**

[tuple](https://docs.python.org/3/library/stdtypes.html#tuple)\[*IR\_OUT*, [*PassManagerState*](/docs/api/qiskit/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")]

### name

`name()`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.5/qiskit/passmanager/base_tasks.py#L72-L74)

Name of the pass.

**Return type**

[str](https://docs.python.org/3/library/stdtypes.html#str)

### run

`run(dag)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.5/qiskit/transpiler/passes/layout/layout_2q_distance.py#L50-L77)

Run the Layout2qDistance pass on dag. :param dag: DAG to evaluate. :type dag: DAGCircuit

### update\_status

`update_status(state, run_state)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.5/qiskit/passmanager/base_tasks.py#L124-L142)

Update workflow status.

**Parameters**

- **state** ([*PassManagerState*](/docs/api/qiskit/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – Pass manager state to update.
- **run\_state** (*RunState*) – Completion status of current task.

**Returns**

Updated pass manager state.

**Return type**

[*PassManagerState*](/docs/api/qiskit/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")