---
title: LayerError (latest version)
description: API reference for qiskit_ibm_runtime.results.LayerError in the latest version of qiskit-ibm-runtime
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit-ibm-runtime/results-layer-error
---

# LayerError

*class* `LayerError(circuit, qubits, error=None)`

[GitHub](https://github.com/Qiskit/qiskit-ibm-runtime/tree/stable/0.49/qiskit_ibm_runtime/results/noise_learner.py#L122-L322)

Bases: `object`

The error channel (in Pauli-Lindblad format) of a single layer of instructions.

**Parameters**

- **circuit** (*QuantumCircuit*) – A circuit whose noise has been learnt.
- **qubits** (*Sequence\[int]*) – The labels of the qubits in the `circuit`.
- **error** ([*PauliLindbladError*](/docs/api/qiskit-ibm-runtime/results-pauli-lindblad-error "qiskit_ibm_runtime.results.PauliLindbladError") *| None*) – The Pauli Lindblad error channel affecting the `circuit`, or `None` if the error channel is either unknown or explicitly disabled.

**Raises**

**ValueError** – If `circuit`, `qubits`, and `error` have mismatching number of qubits.

## Attributes

### circuit

The circuit in this `LayerError`.

### error

The error channel in this `LayerError`, or `None`.

Return `None` if the error channel is either unknown or explicitly disabled.

### num\_qubits

The number of qubits in this [`LayerError`](#qiskit_ibm_runtime.results.LayerError "qiskit_ibm_runtime.results.LayerError").

### qubits

The qubits in this `LayerError`.

## Methods

### draw\_map

`draw_map(embedding, colorscale='Bluered', color_no_data='lightgray', color_out_of_scale='lightgreen', num_edge_segments=16, edge_width=4, height=500, highest_rate=None, background_color='white', radius=0.25, width=800)`

[GitHub](https://github.com/Qiskit/qiskit-ibm-runtime/tree/stable/0.49/qiskit_ibm_runtime/results/noise_learner.py#L174-L251)

Draw a map view of a this layer error.

**Parameters**

- **embedding** (*Embedding | BackendV2*) – An `Embedding` object containing the coordinates and coupling map to draw the layer error on, or a backend to generate an `Embedding` for.
- **colorscale** (*str*) – The colorscale used to show the rates of this layer error.
- **color\_no\_data** (*str*) – The color used for qubits and edges for which no data is available.
- **color\_out\_of\_scale** (*str*) – The color used for rates with value greater than `highest_rate`.
- **num\_edge\_segments** (*int*) – The number of equal-sized segments that edges are made of.
- **edge\_width** (*float*) – The line width of the edges in pixels.
- **height** (*int*) – The height of the returned figure.
- **highest\_rate** (*float | None*) – The highest rate, used to normalize all other rates before choosing their colors. If `None`, it defaults to the highest value found in the `layer_error`.
- **background\_color** (*str*) – The background color.
- **radius** (*float*) – The radius of the pie charts representing the qubits.
- **width** (*int*) – The width of the returned figure.

**Return type**

PlotlyFigure

```python
from qiskit import QuantumCircuit
from qiskit.quantum_info import PauliList
from qiskit_ibm_runtime.utils.embeddings import Embedding
from qiskit_ibm_runtime.results import LayerError, PauliLindbladError

# A five-qubit 1-D embedding with nearest neighbouring connectivity
coordinates1 = [(0, 0), (0, 1), (0, 2), (0, 3), (0, 4), (0, 5)]
coupling_map1 = [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5)]
embedding1 = Embedding(coordinates1, coupling_map1)

# A six-qubit horseshoe-shaped embedding with nearest neighbouring connectivity
coordinates2 = [(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2)]
coupling_map2 = [(0, 1), (1, 2), (0, 3), (3, 4), (4, 5)]
embedding2 = Embedding(coordinates2, coupling_map2)

# A LayerError object
circuit = QuantumCircuit(4)
qubits = [1, 2, 3, 4]
generators = PauliList(["IIIX", "IIXI", "IXII", "YIII", "ZIII", "XXII", "ZZII"])
rates = [0.01, 0.01, 0.01, 0.005, 0.02, 0.01, 0.01]
error = PauliLindbladError(generators, rates)
layer_error = LayerError(circuit, qubits, error)

# Draw the layer error on embedding1
layer_error.draw_map(embedding1)

# Draw the layer error on embedding2
layer_error.draw_map(embedding2)
```

### draw\_swarm

`draw_swarm(num_bodies=None, max_rate=None, min_rate=None, connected=None, colors=None, num_bins=None, opacities=0.4, names=None, x_coo=None, marker_size=None, height=500, width=800)`

[GitHub](https://github.com/Qiskit/qiskit-ibm-runtime/tree/stable/0.49/qiskit_ibm_runtime/results/noise_learner.py#L253-L314)

Draw a swarm plot of the rates in this layer error.

This function plots the rates along a vertical axes, offsetting the rates along the `x` axis so that they do not overlap with each other.

> **Note**
>
> To draw multiple layer errors at once, consider calling [`draw_layer_errors_swarm()`](/docs/api/qiskit-ibm-runtime/visualization-draw-layer-errors-swarm "qiskit_ibm_runtime.visualization.draw_layer_errors_swarm") directly.

**Parameters**

- **num\_bodies** (*int | None*) – The weight of the generators to include in the plot, or `None` if all the generators should be included.
- **max\_rate** (*float | None*) – The largest rate to include in the plot, or `None` if no upper limit should be set.
- **min\_rate** (*float | None*) – The smallest rate to include in the plot, or `None` if no lower limit should be set.
- **connected** (*list\[Pauli] | list\[str] | None*) – A list of generators whose markers are to be connected by lines.
- **colors** (*list\[str] | None*) – A list of colors for the markers in the plot, or `None` if these colors are to be chosen automatically.
- **num\_bins** (*int | None*) – The number of bins to place the rates into when calculating the `x`-axis offsets.
- **opacities** (*float | list\[float]*) – A list of opacities for the markers.
- **names** (*list\[str] | None*) – The names of the various layers as displayed in the legend. If `None`, default names are assigned based on the layers’ position inside the `layer_errors` list.
- **x\_coo** (*list\[float] | None*) – The `x`-axis coordinates of the vertical axes that the markers are drawn around, or `None` if these axes should be placed at regular intervals.
- **marker\_size** (*float | None*) – The size of the marker in the plot.
- **height** (*int*) – The height of the returned figure.
- **width** (*int*) – The width of the returned figure.

**Return type**

PlotlyFigure