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

# Layout

`qiskit_paulice.layout`

Functionality for finding layouts for checks dressed with spacetime Pauli checks.

### get\_low\_overhead\_ancillas

`get_low_overhead_ancillas(coupling_map, layout)`

[GitHub](https://github.com/Qiskit/qiskit-paulice/tree/main/qiskit_paulice/layout.py#L58-L82)

Create a mapping from ancillas to `layout` qubits to which they are adjacent.

**Parameters**

- **coupling\_map** ([*CouplingMap*](/docs/api/qiskit/qiskit.transpiler.CouplingMap)) – A qubit connectivity graph.
- **layout** ([*Sequence*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Sequence)*\[*[*int*](https://docs.python.org/3/library/functions.html#int)*]*) – Physical qubit indices occupied by the payload circuit.

**Returns**

A mapping from ancilla indices to the list of `layout` qubits to which it is adjacent. An ancilla bordering several layout qubits maps to all of them, and a layout qubit bordering several ancillas appears in each of their lists.

**Return type**

[dict](https://docs.python.org/3/library/stdtypes.html#dict)\[[int](https://docs.python.org/3/library/functions.html#int), [list](https://docs.python.org/3/library/stdtypes.html#list)\[[int](https://docs.python.org/3/library/functions.html#int)]]

### get\_check\_qubits

`get_check_qubits(backend, layout)`

[GitHub](https://github.com/Qiskit/qiskit-paulice/tree/main/qiskit_paulice/layout.py#L23-L55)

Pair qubits in `layout` with neighboring ancillas.

Generate equal-length lists of target and ancilla qubits, such that target qubit `i` is adjacent to ancilla qubit `i` in the coupling map. Target and ancilla qubits may appear at most one time in their respective lists.

**Parameters**

- **backend** ([*BackendV2*](/docs/api/qiskit/qiskit.providers.BackendV2)  *|*[*CouplingMap*](/docs/api/qiskit/qiskit.transpiler.CouplingMap)) – The target backend, or a [`CouplingMap`](/docs/api/qiskit/qiskit.transpiler.CouplingMap) describing its connectivity.
- **layout** ([*Sequence*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Sequence)*\[*[*int*](https://docs.python.org/3/library/functions.html#int)*]*) – A list of physical qubit indices.

**Returns**

A length-2 tuple of lists, `(target_qubits, ancilla_qubits)`. `target_qubits[i]` pairs with `ancilla_qubits[i]`.

**Return type**

[tuple](https://docs.python.org/3/library/stdtypes.html#tuple)\[[list](https://docs.python.org/3/library/stdtypes.html#list)\[[int](https://docs.python.org/3/library/functions.html#int)], [list](https://docs.python.org/3/library/stdtypes.html#list)\[[int](https://docs.python.org/3/library/functions.html#int)]]