qiskit-documentation/docs/api/qiskit-ibm-runtime/0.34/utils-noise-learner-result-layer-error.mdx

---
title: LayerError (v0.34)
description: API reference for qiskit_ibm_runtime.utils.noise_learner_result.LayerError in qiskit-ibm-runtime v0.34
in_page_toc_min_heading_level: 1
python_api_type: class
python_api_name: qiskit_ibm_runtime.utils.noise_learner_result.LayerError
---

# LayerError

<Class id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError" isDedicatedPage={true} github="https://github.com/Qiskit/qiskit-ibm-runtime/tree/stable/0.34/qiskit_ibm_runtime/utils/noise_learner_result.py#L137-L376" signature="LayerError(circuit, qubits, error=None)" modifiers="class">
  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** (*Optional\[*[*PauliLindbladError*](utils-noise-learner-result-pauli-lindblad-error "qiskit_ibm_runtime.utils.noise_learner_result.PauliLindbladError")*]*) – 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

  <Attribute id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.circuit">
    The circuit in this `LayerError`.
  </Attribute>

  ### error

  <Attribute id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.error">
    The error channel in this `LayerError`, or `None` if the error channel is either unknown or explicitly disabled.
  </Attribute>

  ### generators

  <Attribute id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.generators">
    (DEPRECATED) The Pauli Lindblad generators of the error channel in this `LayerError`.
  </Attribute>

  ### num\_qubits

  <Attribute id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.num_qubits">
    The number of qubits in this [`LayerError`](#qiskit_ibm_runtime.utils.noise_learner_result.LayerError "qiskit_ibm_runtime.utils.noise_learner_result.LayerError").
  </Attribute>

  ### qubits

  <Attribute id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.qubits">
    The qubits in this `LayerError`.
  </Attribute>

  ### rates

  <Attribute id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.rates">
    (DEPRECATED) The Lindblad generator rates of the error channel in this `LayerError`.
  </Attribute>

  ## Methods

  ### draw\_map

  <Function id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.draw_map" github="https://github.com/Qiskit/qiskit-ibm-runtime/tree/stable/0.34/qiskit_ibm_runtime/utils/noise_learner_result.py#L222-L302" signature="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)">
    Draw a map view of a this layer error.

    **Parameters**

    *   **embedding** (*Union\[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** (*Optional\[float]*) – 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.utils.noise_learner_result 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)
    ```
  </Function>

  ### draw\_swarm

  <Function id="qiskit_ibm_runtime.utils.noise_learner_result.LayerError.draw_swarm" github="https://github.com/Qiskit/qiskit-ibm-runtime/tree/stable/0.34/qiskit_ibm_runtime/utils/noise_learner_result.py#L304-L368" signature="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)">
    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.

    <Admonition title="Note" type="note">
      To draw multiple layer errors at once, consider calling [`draw_layer_errors_swarm()`](visualization-draw-layer-errors-swarm "qiskit_ibm_runtime.visualization.draw_layer_errors_swarm") directly.
    </Admonition>

    **Parameters**

    *   **num\_bodies** (*Optional\[int]*) – The weight of the generators to include in the plot, or `None` if all the generators should be included.
    *   **max\_rate** (*Optional\[float]*) – The largest rate to include in the plot, or `None` if no upper limit should be set.
    *   **min\_rate** (*Optional\[float]*) – The smallest rate to include in the plot, or `None` if no lower limit should be set.
    *   **connected** (*Optional\[Union\[list\[Pauli], list\[str]]]*) – A list of generators whose markers are to be connected by lines.
    *   **colors** (*Optional\[list\[str]]*) – A list of colors for the markers in the plot, or `None` if these colors are to be chosen automatically.
    *   **num\_bins** (*Optional\[int]*) – The number of bins to place the rates into when calculating the `x`-axis offsets.
    *   **opacities** (*Union\[float, list\[float]]*) – A list of opacities for the markers.
    *   **names** (*Optional\[list\[str]]*) – 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** (*Optional\[list\[float]]*) – 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** (*Optional\[float]*) – 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
  </Function>
</Class>