# This code is part of Qiskit.
#
# (C) Copyright IBM 2017, 2018.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.
"""A module for visualizing device coupling maps"""
import math
from typing import List
import numpy as np
import rustworkx as rx
from rustworkx.visualization import graphviz_draw
from qiskit.exceptions import QiskitError
from qiskit.utils import optionals as _optionals
from qiskit.providers.exceptions import BackendPropertyError
from qiskit.transpiler.coupling import CouplingMap
from .exceptions import VisualizationError
def _get_backend_interface_version(backend):
backend_interface_version = getattr(backend, "version", None)
return backend_interface_version
[docs]@_optionals.HAS_MATPLOTLIB.require_in_call
def plot_gate_map(
backend,
figsize=None,
plot_directed=False,
label_qubits=True,
qubit_size=None,
line_width=4,
font_size=None,
qubit_color=None,
qubit_labels=None,
line_color=None,
font_color="white",
ax=None,
filename=None,
qubit_coordinates=None,
):
"""Plots the gate map of a device.
Args:
backend (Backend): The backend instance that will be used to plot the device
gate map.
figsize (tuple): Output figure size (wxh) in inches.
plot_directed (bool): Plot directed coupling map.
label_qubits (bool): Label the qubits.
qubit_size (float): Size of qubit marker.
line_width (float): Width of lines.
font_size (int): Font size of qubit labels.
qubit_color (list): A list of colors for the qubits
qubit_labels (list): A list of qubit labels
line_color (list): A list of colors for each line from coupling_map.
font_color (str): The font color for the qubit labels.
ax (Axes): A Matplotlib axes instance.
filename (str): file path to save image to.
qubit_coordinates (Sequence): An optional sequence input (list or array being the
most common) of 2d coordinates for each qubit. The length of the
sequence much match the number of qubits on the backend. The sequence
should be the planar coordinates in a 0-based square grid where each
qubit is located.
Returns:
Figure: A Matplotlib figure instance.
Raises:
QiskitError: if tried to pass a simulator, or if the backend is None,
but one of num_qubits, mpl_data, or cmap is None.
MissingOptionalLibraryError: if matplotlib not installed.
Example:
.. plot::
:include-source:
from qiskit import QuantumCircuit, execute
from qiskit.providers.fake_provider import FakeVigoV2
from qiskit.visualization import plot_gate_map
backend = FakeVigoV2()
plot_gate_map(backend)
"""
qubit_coordinates_map = {}
qubit_coordinates_map[5] = [[1, 0], [0, 1], [1, 1], [1, 2], [2, 1]]
qubit_coordinates_map[7] = [[0, 0], [0, 1], [0, 2], [1, 1], [2, 0], [2, 1], [2, 2]]
qubit_coordinates_map[20] = [
[0, 0],
[0, 1],
[0, 2],
[0, 3],
[0, 4],
[1, 0],
[1, 1],
[1, 2],
[1, 3],
[1, 4],
[2, 0],
[2, 1],
[2, 2],
[2, 3],
[2, 4],
[3, 0],
[3, 1],
[3, 2],
[3, 3],
[3, 4],
]
qubit_coordinates_map[15] = [
[0, 0],
[0, 1],
[0, 2],
[0, 3],
[0, 4],
[0, 5],
[0, 6],
[1, 7],
[1, 6],
[1, 5],
[1, 4],
[1, 3],
[1, 2],
[1, 1],
[1, 0],
]
qubit_coordinates_map[16] = [
[1, 0],
[1, 1],
[2, 1],
[3, 1],
[1, 2],
[3, 2],
[0, 3],
[1, 3],
[3, 3],
[4, 3],
[1, 4],
[3, 4],
[1, 5],
[2, 5],
[3, 5],
[1, 6],
]
qubit_coordinates_map[27] = [
[1, 0],
[1, 1],
[2, 1],
[3, 1],
[1, 2],
[3, 2],
[0, 3],
[1, 3],
[3, 3],
[4, 3],
[1, 4],
[3, 4],
[1, 5],
[2, 5],
[3, 5],
[1, 6],
[3, 6],
[0, 7],
[1, 7],
[3, 7],
[4, 7],
[1, 8],
[3, 8],
[1, 9],
[2, 9],
[3, 9],
[3, 10],
]
qubit_coordinates_map[28] = [
[0, 2],
[0, 3],
[0, 4],
[0, 5],
[0, 6],
[1, 2],
[1, 6],
[2, 0],
[2, 1],
[2, 2],
[2, 3],
[2, 4],
[2, 5],
[2, 6],
[2, 7],
[2, 8],
[3, 0],
[3, 4],
[3, 8],
[4, 0],
[4, 1],
[4, 2],
[4, 3],
[4, 4],
[4, 5],
[4, 6],
[4, 7],
[4, 8],
]
qubit_coordinates_map[53] = [
[0, 2],
[0, 3],
[0, 4],
[0, 5],
[0, 6],
[1, 2],
[1, 6],
[2, 0],
[2, 1],
[2, 2],
[2, 3],
[2, 4],
[2, 5],
[2, 6],
[2, 7],
[2, 8],
[3, 0],
[3, 4],
[3, 8],
[4, 0],
[4, 1],
[4, 2],
[4, 3],
[4, 4],
[4, 5],
[4, 6],
[4, 7],
[4, 8],
[5, 2],
[5, 6],
[6, 0],
[6, 1],
[6, 2],
[6, 3],
[6, 4],
[6, 5],
[6, 6],
[6, 7],
[6, 8],
[7, 0],
[7, 4],
[7, 8],
[8, 0],
[8, 1],
[8, 2],
[8, 3],
[8, 4],
[8, 5],
[8, 6],
[8, 7],
[8, 8],
[9, 2],
[9, 6],
]
qubit_coordinates_map[65] = [
[0, 0],
[0, 1],
[0, 2],
[0, 3],
[0, 4],
[0, 5],
[0, 6],
[0, 7],
[0, 8],
[0, 9],
[1, 0],
[1, 4],
[1, 8],
[2, 0],
[2, 1],
[2, 2],
[2, 3],
[2, 4],
[2, 5],
[2, 6],
[2, 7],
[2, 8],
[2, 9],
[2, 10],
[3, 2],
[3, 6],
[3, 10],
[4, 0],
[4, 1],
[4, 2],
[4, 3],
[4, 4],
[4, 5],
[4, 6],
[4, 7],
[4, 8],
[4, 9],
[4, 10],
[5, 0],
[5, 4],
[5, 8],
[6, 0],
[6, 1],
[6, 2],
[6, 3],
[6, 4],
[6, 5],
[6, 6],
[6, 7],
[6, 8],
[6, 9],
[6, 10],
[7, 2],
[7, 6],
[7, 10],
[8, 1],
[8, 2],
[8, 3],
[8, 4],
[8, 5],
[8, 6],
[8, 7],
[8, 8],
[8, 9],
[8, 10],
]
qubit_coordinates_map[127] = [
[0, 0],
[0, 1],
[0, 2],
[0, 3],
[0, 4],
[0, 5],
[0, 6],
[0, 7],
[0, 8],
[0, 9],
[0, 10],
[0, 11],
[0, 12],
[0, 13],
[1, 0],
[1, 4],
[1, 8],
[1, 12],
[2, 0],
[2, 1],
[2, 2],
[2, 3],
[2, 4],
[2, 5],
[2, 6],
[2, 7],
[2, 8],
[2, 9],
[2, 10],
[2, 11],
[2, 12],
[2, 13],
[2, 14],
[3, 2],
[3, 6],
[3, 10],
[3, 14],
[4, 0],
[4, 1],
[4, 2],
[4, 3],
[4, 4],
[4, 5],
[4, 6],
[4, 7],
[4, 8],
[4, 9],
[4, 10],
[4, 11],
[4, 12],
[4, 13],
[4, 14],
[5, 0],
[5, 4],
[5, 8],
[5, 12],
[6, 0],
[6, 1],
[6, 2],
[6, 3],
[6, 4],
[6, 5],
[6, 6],
[6, 7],
[6, 8],
[6, 9],
[6, 10],
[6, 11],
[6, 12],
[6, 13],
[6, 14],
[7, 2],
[7, 6],
[7, 10],
[7, 14],
[8, 0],
[8, 1],
[8, 2],
[8, 3],
[8, 4],
[8, 5],
[8, 6],
[8, 7],
[8, 8],
[8, 9],
[8, 10],
[8, 11],
[8, 12],
[8, 13],
[8, 14],
[9, 0],
[9, 4],
[9, 8],
[9, 12],
[10, 0],
[10, 1],
[10, 2],
[10, 3],
[10, 4],
[10, 5],
[10, 6],
[10, 7],
[10, 8],
[10, 9],
[10, 10],
[10, 11],
[10, 12],
[10, 13],
[10, 14],
[11, 2],
[11, 6],
[11, 10],
[11, 14],
[12, 1],
[12, 2],
[12, 3],
[12, 4],
[12, 5],
[12, 6],
[12, 7],
[12, 8],
[12, 9],
[12, 10],
[12, 11],
[12, 12],
[12, 13],
[12, 14],
]
qubit_coordinates_map[433] = [
[0, 0],
[0, 1],
[0, 2],
[0, 3],
[0, 4],
[0, 5],
[0, 6],
[0, 7],
[0, 8],
[0, 9],
[0, 10],
[0, 11],
[0, 12],
[0, 13],
[0, 14],
[0, 15],
[0, 16],
[0, 17],
[0, 18],
[0, 19],
[0, 20],
[0, 21],
[0, 22],
[0, 23],
[0, 24],
[0, 25],
[1, 0],
[1, 4],
[1, 8],
[1, 12],
[1, 16],
[1, 20],
[1, 24],
[2, 0],
[2, 1],
[2, 2],
[2, 3],
[2, 4],
[2, 5],
[2, 6],
[2, 7],
[2, 8],
[2, 9],
[2, 10],
[2, 11],
[2, 12],
[2, 13],
[2, 14],
[2, 15],
[2, 16],
[2, 17],
[2, 18],
[2, 19],
[2, 20],
[2, 21],
[2, 22],
[2, 23],
[2, 24],
[2, 25],
[2, 26],
[3, 2],
[3, 6],
[3, 10],
[3, 14],
[3, 18],
[3, 22],
[3, 26],
[4, 0],
[4, 1],
[4, 2],
[4, 3],
[4, 4],
[4, 5],
[4, 6],
[4, 7],
[4, 8],
[4, 9],
[4, 10],
[4, 11],
[4, 12],
[4, 13],
[4, 14],
[4, 15],
[4, 16],
[4, 17],
[4, 18],
[4, 19],
[4, 20],
[4, 21],
[4, 22],
[4, 23],
[4, 24],
[4, 25],
[4, 26],
[5, 0],
[5, 4],
[5, 8],
[5, 12],
[5, 16],
[5, 20],
[5, 24],
[6, 0],
[6, 1],
[6, 2],
[6, 3],
[6, 4],
[6, 5],
[6, 6],
[6, 7],
[6, 8],
[6, 9],
[6, 10],
[6, 11],
[6, 12],
[6, 13],
[6, 14],
[6, 15],
[6, 16],
[6, 17],
[6, 18],
[6, 19],
[6, 20],
[6, 21],
[6, 22],
[6, 23],
[6, 24],
[6, 25],
[6, 26],
[7, 2],
[7, 6],
[7, 10],
[7, 14],
[7, 18],
[7, 22],
[7, 26],
[8, 0],
[8, 1],
[8, 2],
[8, 3],
[8, 4],
[8, 5],
[8, 6],
[8, 7],
[8, 8],
[8, 9],
[8, 10],
[8, 11],
[8, 12],
[8, 13],
[8, 14],
[8, 15],
[8, 16],
[8, 17],
[8, 18],
[8, 19],
[8, 20],
[8, 21],
[8, 22],
[8, 23],
[8, 24],
[8, 25],
[8, 26],
[9, 0],
[9, 4],
[9, 8],
[9, 12],
[9, 16],
[9, 20],
[9, 24],
[10, 0],
[10, 1],
[10, 2],
[10, 3],
[10, 4],
[10, 5],
[10, 6],
[10, 7],
[10, 8],
[10, 9],
[10, 10],
[10, 11],
[10, 12],
[10, 13],
[10, 14],
[10, 15],
[10, 16],
[10, 17],
[10, 18],
[10, 19],
[10, 20],
[10, 21],
[10, 22],
[10, 23],
[10, 24],
[10, 25],
[10, 26],
[11, 2],
[11, 6],
[11, 10],
[11, 14],
[11, 18],
[11, 22],
[11, 26],
[12, 0],
[12, 1],
[12, 2],
[12, 3],
[12, 4],
[12, 5],
[12, 6],
[12, 7],
[12, 8],
[12, 9],
[12, 10],
[12, 11],
[12, 12],
[12, 13],
[12, 14],
[12, 15],
[12, 16],
[12, 17],
[12, 18],
[12, 19],
[12, 20],
[12, 21],
[12, 22],
[12, 23],
[12, 24],
[12, 25],
[12, 26],
[13, 0],
[13, 4],
[13, 8],
[13, 12],
[13, 16],
[13, 20],
[13, 24],
[14, 0],
[14, 1],
[14, 2],
[14, 3],
[14, 4],
[14, 5],
[14, 6],
[14, 7],
[14, 8],
[14, 9],
[14, 10],
[14, 11],
[14, 12],
[14, 13],
[14, 14],
[14, 15],
[14, 16],
[14, 17],
[14, 18],
[14, 19],
[14, 20],
[14, 21],
[14, 22],
[14, 23],
[14, 24],
[14, 25],
[14, 26],
[15, 2],
[15, 6],
[15, 10],
[15, 14],
[15, 18],
[15, 22],
[15, 26],
[16, 0],
[16, 1],
[16, 2],
[16, 3],
[16, 4],
[16, 5],
[16, 6],
[16, 7],
[16, 8],
[16, 9],
[16, 10],
[16, 11],
[16, 12],
[16, 13],
[16, 14],
[16, 15],
[16, 16],
[16, 17],
[16, 18],
[16, 19],
[16, 20],
[16, 21],
[16, 22],
[16, 23],
[16, 24],
[16, 25],
[16, 26],
[17, 0],
[17, 4],
[17, 8],
[17, 12],
[17, 16],
[17, 20],
[17, 24],
[18, 0],
[18, 1],
[18, 2],
[18, 3],
[18, 4],
[18, 5],
[18, 6],
[18, 7],
[18, 8],
[18, 9],
[18, 10],
[18, 11],
[18, 12],
[18, 13],
[18, 14],
[18, 15],
[18, 16],
[18, 17],
[18, 18],
[18, 19],
[18, 20],
[18, 21],
[18, 22],
[18, 23],
[18, 24],
[18, 25],
[18, 26],
[19, 2],
[19, 6],
[19, 10],
[19, 14],
[19, 18],
[19, 22],
[19, 26],
[20, 0],
[20, 1],
[20, 2],
[20, 3],
[20, 4],
[20, 5],
[20, 6],
[20, 7],
[20, 8],
[20, 9],
[20, 10],
[20, 11],
[20, 12],
[20, 13],
[20, 14],
[20, 15],
[20, 16],
[20, 17],
[20, 18],
[20, 19],
[20, 20],
[20, 21],
[20, 22],
[20, 23],
[20, 24],
[20, 25],
[20, 26],
[21, 0],
[21, 4],
[21, 8],
[21, 12],
[21, 16],
[21, 20],
[21, 24],
[22, 0],
[22, 1],
[22, 2],
[22, 3],
[22, 4],
[22, 5],
[22, 6],
[22, 7],
[22, 8],
[22, 9],
[22, 10],
[22, 11],
[22, 12],
[22, 13],
[22, 14],
[22, 15],
[22, 16],
[22, 17],
[22, 18],
[22, 19],
[22, 20],
[22, 21],
[22, 22],
[22, 23],
[22, 24],
[22, 25],
[22, 26],
[23, 2],
[23, 6],
[23, 10],
[23, 14],
[23, 18],
[23, 22],
[23, 26],
[24, 1],
[24, 2],
[24, 3],
[24, 4],
[24, 5],
[24, 6],
[24, 7],
[24, 8],
[24, 9],
[24, 10],
[24, 11],
[24, 12],
[24, 13],
[24, 14],
[24, 15],
[24, 16],
[24, 17],
[24, 18],
[24, 19],
[24, 20],
[24, 21],
[24, 22],
[24, 23],
[24, 24],
[24, 25],
[24, 26],
]
backend_version = _get_backend_interface_version(backend)
if backend_version <= 1:
if backend.configuration().simulator:
raise QiskitError("Requires a device backend, not simulator.")
config = backend.configuration()
num_qubits = config.n_qubits
coupling_map = CouplingMap(config.coupling_map)
name = backend.name()
else:
num_qubits = backend.num_qubits
coupling_map = backend.coupling_map
name = backend.name
if qubit_coordinates is None and ("ibm" in name or "fake" in name):
qubit_coordinates = qubit_coordinates_map.get(num_qubits, None)
if qubit_coordinates:
if len(qubit_coordinates) != num_qubits:
raise QiskitError(
f"The number of specified qubit coordinates {len(qubit_coordinates)} "
f"does not match the device number of qubits: {num_qubits}"
)
return plot_coupling_map(
num_qubits,
qubit_coordinates,
coupling_map.get_edges(),
figsize,
plot_directed,
label_qubits,
qubit_size,
line_width,
font_size,
qubit_color,
qubit_labels,
line_color,
font_color,
ax,
filename,
)
[docs]@_optionals.HAS_MATPLOTLIB.require_in_call
@_optionals.HAS_GRAPHVIZ.require_in_call
def plot_coupling_map(
num_qubits: int,
qubit_coordinates: List[List[int]],
coupling_map: List[List[int]],
figsize=None,
plot_directed=False,
label_qubits=True,
qubit_size=None,
line_width=4,
font_size=None,
qubit_color=None,
qubit_labels=None,
line_color=None,
font_color="white",
ax=None,
filename=None,
):
"""Plots an arbitrary coupling map of qubits (embedded in a plane).
Args:
num_qubits (int): The number of qubits defined and plotted.
qubit_coordinates (List[List[int]]): A list of two-element lists, with entries of each nested
list being the planar coordinates in a 0-based square grid where each qubit is located.
coupling_map (List[List[int]]): A list of two-element lists, with entries of each nested
list being the qubit numbers of the bonds to be plotted.
figsize (tuple): Output figure size (wxh) in inches.
plot_directed (bool): Plot directed coupling map.
label_qubits (bool): Label the qubits.
qubit_size (float): Size of qubit marker.
line_width (float): Width of lines.
font_size (int): Font size of qubit labels.
qubit_color (list): A list of colors for the qubits
qubit_labels (list): A list of qubit labels
line_color (list): A list of colors for each line from coupling_map.
font_color (str): The font color for the qubit labels.
ax (Axes): A Matplotlib axes instance.
filename (str): file path to save image to.
Returns:
Figure: A Matplotlib figure instance.
Raises:
MissingOptionalLibraryError: If matplotlib or graphviz is not installed.
QiskitError: If length of qubit labels does not match number of qubits.
Example:
.. plot::
:include-source:
from qiskit.visualization import plot_coupling_map
num_qubits = 8
qubit_coordinates = [[0, 1], [1, 1], [1, 0], [1, 2], [2, 0], [2, 2], [2, 1], [3, 1]]
coupling_map = [[0, 1], [1, 2], [2, 3], [3, 5], [4, 5], [5, 6], [2, 4], [6, 7]]
plot_coupling_map(num_qubits, qubit_coordinates, coupling_map)
"""
import matplotlib.pyplot as plt
from .utils import matplotlib_close_if_inline
input_axes = False
if ax:
input_axes = True
if qubit_size is None:
qubit_size = 30
if qubit_labels is None:
qubit_labels = list(range(num_qubits))
else:
if len(qubit_labels) != num_qubits:
raise QiskitError("Length of qubit labels does not equal number of qubits.")
if not label_qubits:
qubit_labels = [""] * num_qubits
# set coloring
if qubit_color is None:
qubit_color = ["#648fff"] * num_qubits
if line_color is None:
line_color = ["#648fff"] * len(coupling_map)
if num_qubits == 1:
graph = rx.PyDiGraph()
graph.add_node(0)
else:
graph = CouplingMap(coupling_map).graph
if not plot_directed:
graph = graph.to_undirected(multigraph=False)
for node in graph.node_indices():
graph[node] = node
for edge_index in graph.edge_indices():
graph.update_edge_by_index(edge_index, edge_index)
# pixel-to-inch conversion
px = 1.15 / plt.rcParams["figure.dpi"]
if qubit_coordinates:
qubit_coordinates = [coordinates[::-1] for coordinates in qubit_coordinates]
if font_size is None:
max_characters = max(1, max(len(str(x)) for x in qubit_labels))
font_size = max(int(20 / max_characters), 1)
def color_node(node):
if qubit_coordinates:
out_dict = {
"label": str(qubit_labels[node]),
"color": f'"{qubit_color[node]}"',
"fillcolor": f'"{qubit_color[node]}"',
"style": "filled",
"shape": "circle",
"pos": f'"{qubit_coordinates[node][0]},{qubit_coordinates[node][1]}"',
"pin": "True",
}
else:
out_dict = {
"label": str(qubit_labels[node]),
"color": f'"{qubit_color[node]}"',
"fillcolor": f'"{qubit_color[node]}"',
"style": "filled",
"shape": "circle",
}
out_dict["fontcolor"] = f'"{font_color}"'
out_dict["fontsize"] = str(font_size)
out_dict["height"] = str(qubit_size * px)
out_dict["fixedsize"] = "True"
out_dict["fontname"] = '"DejaVu Sans"'
return out_dict
def color_edge(edge):
out_dict = {
"color": f'"{line_color[edge]}"',
"fillcolor": f'"{line_color[edge]}"',
"penwidth": str(line_width),
}
return out_dict
plot = graphviz_draw(
graph,
method="neato",
node_attr_fn=color_node,
edge_attr_fn=color_edge,
filename=filename,
)
if filename:
return None
if not input_axes:
if figsize is None:
width, height = plot.size
figsize = (width * px, height * px)
fig, ax = plt.subplots(figsize=figsize)
ax.axis("off")
ax.imshow(plot)
if not input_axes:
matplotlib_close_if_inline(fig)
return fig
[docs]def plot_circuit_layout(circuit, backend, view="virtual", qubit_coordinates=None):
"""Plot the layout of a circuit transpiled for a given
target backend.
Args:
circuit (QuantumCircuit): Input quantum circuit.
backend (Backend): Target backend.
view (str): Layout view: either 'virtual' or 'physical'.
qubit_coordinates (Sequence): An optional sequence input (list or array being the
most common) of 2d coordinates for each qubit. The length of the
sequence must match the number of qubits on the backend. The sequence
should be the planar coordinates in a 0-based square grid where each
qubit is located.
Returns:
Figure: A matplotlib figure showing layout.
Raises:
QiskitError: Invalid view type given.
VisualizationError: Circuit has no layout attribute.
Example:
.. plot::
:include-source:
import numpy as np
from qiskit import QuantumCircuit, transpile
from qiskit.providers.fake_provider import FakeVigoV2
from qiskit.visualization import plot_circuit_layout
from qiskit.tools.monitor import job_monitor
from qiskit.providers.fake_provider import FakeVigoV2
import matplotlib.pyplot as plt
ghz = QuantumCircuit(3, 3)
ghz.h(0)
for idx in range(1,3):
ghz.cx(0,idx)
ghz.measure(range(3), range(3))
backend = FakeVigoV2()
new_circ_lv3 = transpile(ghz, backend=backend, optimization_level=3)
plot_circuit_layout(new_circ_lv3, backend)
"""
if circuit._layout is None:
raise QiskitError("Circuit has no layout. Perhaps it has not been transpiled.")
backend_version = _get_backend_interface_version(backend)
if backend_version <= 1:
num_qubits = backend.configuration().n_qubits
cmap = backend.configuration().coupling_map
cmap_len = len(cmap)
else:
num_qubits = backend.num_qubits
cmap = backend.coupling_map
cmap_len = cmap.graph.num_edges()
qubits = []
qubit_labels = [""] * num_qubits
bit_locations = {
bit: {"register": register, "index": index}
for register in circuit._layout.initial_layout.get_registers()
for index, bit in enumerate(register)
}
for index, qubit in enumerate(circuit._layout.initial_layout.get_virtual_bits()):
if qubit not in bit_locations:
bit_locations[qubit] = {"register": None, "index": index}
if view == "virtual":
for key, val in circuit._layout.initial_layout.get_virtual_bits().items():
bit_register = bit_locations[key]["register"]
if bit_register is None or bit_register.name != "ancilla":
qubits.append(val)
qubit_labels[val] = str(bit_locations[key]["index"])
elif view == "physical":
for key, val in circuit._layout.initial_layout.get_physical_bits().items():
bit_register = bit_locations[val]["register"]
if bit_register is None or bit_register.name != "ancilla":
qubits.append(key)
qubit_labels[key] = str(key)
else:
raise VisualizationError("Layout view must be 'virtual' or 'physical'.")
qcolors = ["#648fff"] * num_qubits
for k in qubits:
qcolors[k] = "black"
lcolors = ["#648fff"] * cmap_len
for idx, edge in enumerate(cmap):
if edge[0] in qubits and edge[1] in qubits:
lcolors[idx] = "black"
fig = plot_gate_map(
backend,
qubit_color=qcolors,
qubit_labels=qubit_labels,
line_color=lcolors,
qubit_coordinates=qubit_coordinates,
)
return fig
[docs]@_optionals.HAS_MATPLOTLIB.require_in_call
@_optionals.HAS_SEABORN.require_in_call
def plot_error_map(backend, figsize=(15, 12), show_title=True, qubit_coordinates=None):
"""Plots the error map of a given backend.
Args:
backend (Backend): Given backend.
figsize (tuple): Figure size in inches.
show_title (bool): Show the title or not.
qubit_coordinates (Sequence): An optional sequence input (list or array being the
most common) of 2d coordinates for each qubit. The length of the
sequence much mast the number of qubits on the backend. The sequence
should be the planar coordinates in a 0-based square grid where each
qubit is located.
Returns:
Figure: A matplotlib figure showing error map.
Raises:
VisualizationError: The backend does not provide gate errors for the 'sx' gate.
MissingOptionalLibraryError: If matplotlib or seaborn is not installed.
Example:
.. plot::
:include-source:
from qiskit import QuantumCircuit, execute
from qiskit.visualization import plot_error_map
from qiskit.providers.fake_provider import FakeVigoV2
backend = FakeVigoV2()
plot_error_map(backend)
"""
import matplotlib
import matplotlib.pyplot as plt
from matplotlib import gridspec, ticker
import seaborn as sns
from .utils import matplotlib_close_if_inline
color_map = sns.cubehelix_palette(reverse=True, as_cmap=True)
backend_version = _get_backend_interface_version(backend)
if backend_version <= 1:
backend_name = backend.name()
num_qubits = backend.configuration().n_qubits
cmap = backend.configuration().coupling_map
props = backend.properties()
props_dict = props.to_dict()
single_gate_errors = [0] * num_qubits
read_err = [0] * num_qubits
cx_errors = []
# sx error rates
for gate in props_dict["gates"]:
if gate["gate"] == "sx":
_qubit = gate["qubits"][0]
for param in gate["parameters"]:
if param["name"] == "gate_error":
single_gate_errors[_qubit] = param["value"]
break
else:
raise VisualizationError(
f"Backend '{backend}' did not supply an error for the 'sx' gate."
)
if cmap:
directed = False
if num_qubits < 20:
for edge in cmap:
if not [edge[1], edge[0]] in cmap:
directed = True
break
for line in cmap:
for item in props_dict["gates"]:
if item["qubits"] == line:
cx_errors.append(item["parameters"][0]["value"])
break
for qubit in range(num_qubits):
try:
read_err[qubit] = props.readout_error(qubit)
except BackendPropertyError:
pass
else:
backend_name = backend.name
num_qubits = backend.num_qubits
cmap = backend.coupling_map
two_q_error_map = {}
single_gate_errors = [0] * num_qubits
read_err = [0] * num_qubits
cx_errors = []
for gate, prop_dict in backend.target.items():
if prop_dict is None or None in prop_dict:
continue
for qargs, inst_props in prop_dict.items():
if inst_props is None:
continue
if gate == "measure":
if inst_props.error is not None:
read_err[qargs[0]] = inst_props.error
elif len(qargs) == 1:
if inst_props.error is not None:
single_gate_errors[qargs[0]] = max(
single_gate_errors[qargs[0]], inst_props.error
)
elif len(qargs) == 2:
if inst_props.error is not None:
two_q_error_map[qargs] = max(
two_q_error_map.get(qargs, 0), inst_props.error
)
if cmap:
directed = False
if num_qubits < 20:
for edge in cmap:
if not [edge[1], edge[0]] in cmap:
directed = True
break
for line in cmap.get_edges():
err = two_q_error_map.get(tuple(line), 0)
cx_errors.append(err)
# Convert to percent
single_gate_errors = 100 * np.asarray(single_gate_errors)
avg_1q_err = np.mean(single_gate_errors)
single_norm = matplotlib.colors.Normalize(
vmin=min(single_gate_errors), vmax=max(single_gate_errors)
)
q_colors = [matplotlib.colors.to_hex(color_map(single_norm(err))) for err in single_gate_errors]
directed = False
line_colors = []
if cmap:
# Convert to percent
cx_errors = 100 * np.asarray(cx_errors)
avg_cx_err = np.mean(cx_errors)
cx_norm = matplotlib.colors.Normalize(vmin=min(cx_errors), vmax=max(cx_errors))
line_colors = [matplotlib.colors.to_hex(color_map(cx_norm(err))) for err in cx_errors]
read_err = 100 * np.asarray(read_err)
avg_read_err = np.mean(read_err)
max_read_err = np.max(read_err)
fig = plt.figure(figsize=figsize)
gridspec.GridSpec(nrows=2, ncols=3)
grid_spec = gridspec.GridSpec(
12, 12, height_ratios=[1] * 11 + [0.5], width_ratios=[2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2]
)
left_ax = plt.subplot(grid_spec[2:10, :1])
main_ax = plt.subplot(grid_spec[:11, 1:11])
right_ax = plt.subplot(grid_spec[2:10, 11:])
bleft_ax = plt.subplot(grid_spec[-1, :5])
if cmap:
bright_ax = plt.subplot(grid_spec[-1, 7:])
qubit_size = 28
if num_qubits <= 5:
qubit_size = 20
plot_gate_map(
backend,
qubit_color=q_colors,
line_color=line_colors,
qubit_size=qubit_size,
line_width=5,
plot_directed=directed,
ax=main_ax,
qubit_coordinates=qubit_coordinates,
)
main_ax.axis("off")
main_ax.set_aspect(1)
if cmap:
single_cb = matplotlib.colorbar.ColorbarBase(
bleft_ax, cmap=color_map, norm=single_norm, orientation="horizontal"
)
tick_locator = ticker.MaxNLocator(nbins=5)
single_cb.locator = tick_locator
single_cb.update_ticks()
single_cb.update_ticks()
bleft_ax.set_title(f"H error rate (%) [Avg. = {round(avg_1q_err, 3)}]")
if cmap is None:
bleft_ax.axis("off")
bleft_ax.set_title(f"H error rate (%) = {round(avg_1q_err, 3)}")
if cmap:
cx_cb = matplotlib.colorbar.ColorbarBase(
bright_ax, cmap=color_map, norm=cx_norm, orientation="horizontal"
)
tick_locator = ticker.MaxNLocator(nbins=5)
cx_cb.locator = tick_locator
cx_cb.update_ticks()
bright_ax.set_title(f"CNOT error rate (%) [Avg. = {round(avg_cx_err, 3)}]")
if num_qubits < 10:
num_left = num_qubits
num_right = 0
else:
num_left = math.ceil(num_qubits / 2)
num_right = num_qubits - num_left
left_ax.barh(range(num_left), read_err[:num_left], align="center", color="#DDBBBA")
left_ax.axvline(avg_read_err, linestyle="--", color="#212121")
left_ax.set_yticks(range(num_left))
left_ax.set_xticks([0, round(avg_read_err, 2), round(max_read_err, 2)])
left_ax.set_yticklabels([str(kk) for kk in range(num_left)], fontsize=12)
left_ax.invert_yaxis()
left_ax.set_title("Readout Error (%)", fontsize=12)
for spine in left_ax.spines.values():
spine.set_visible(False)
if num_right:
right_ax.barh(
range(num_left, num_qubits), read_err[num_left:], align="center", color="#DDBBBA"
)
right_ax.axvline(avg_read_err, linestyle="--", color="#212121")
right_ax.set_yticks(range(num_left, num_qubits))
right_ax.set_xticks([0, round(avg_read_err, 2), round(max_read_err, 2)])
right_ax.set_yticklabels([str(kk) for kk in range(num_left, num_qubits)], fontsize=12)
right_ax.invert_yaxis()
right_ax.invert_xaxis()
right_ax.yaxis.set_label_position("right")
right_ax.yaxis.tick_right()
right_ax.set_title("Readout Error (%)", fontsize=12)
else:
right_ax.axis("off")
for spine in right_ax.spines.values():
spine.set_visible(False)
if show_title:
fig.suptitle(f"{backend_name} Error Map", fontsize=24, y=0.9)
matplotlib_close_if_inline(fig)
return fig