# 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.
"""
Module for the primary interface to the circuit drawers.
This module contains the end user facing API for drawing quantum circuits.
There are 3 available drawer backends:
0. ASCII art
1. LaTeX
2. Matplotlib
This provides a single function entry point to drawing a circuit object with
any of the backends.
"""
import logging
import os
import subprocess
import tempfile
import shutil
from warnings import warn
from qiskit import user_config
from qiskit.utils import optionals as _optionals
from . import latex as _latex
from . import text as _text
from . import matplotlib as _matplotlib
from . import _utils
from ..utils import _trim as trim_image
from ..exceptions import VisualizationError
logger = logging.getLogger(__name__)
[docs]def circuit_drawer(
circuit,
scale=None,
filename=None,
style=None,
output=None,
interactive=False,
plot_barriers=True,
reverse_bits=None,
justify=None,
vertical_compression="medium",
idle_wires=True,
with_layout=True,
fold=None,
ax=None,
initial_state=False,
cregbundle=None,
wire_order=None,
):
"""Draw the quantum circuit. Use the output parameter to choose the drawing format:
**text**: ASCII art TextDrawing that can be printed in the console.
**matplotlib**: images with color rendered purely in Python.
**latex**: high-quality images compiled via latex.
**latex_source**: raw uncompiled latex output.
.. warning::
Support for :class:`~.expr.Expr` nodes in conditions and :attr:`.SwitchCaseOp.target` fields
is preliminary and incomplete. The ``text`` and ``mpl`` drawers will make a best-effort
attempt to show data dependencies, but the LaTeX-based drawers will skip these completely.
Args:
circuit (QuantumCircuit): the quantum circuit to draw
scale (float): scale of image to draw (shrink if < 1.0). Only used by
the `mpl`, `latex` and `latex_source` outputs. Defaults to 1.0.
filename (str): file path to save image to. Defaults to None.
style (dict or str): dictionary of style or file name of style json file.
This option is only used by the `mpl` or `latex` output type.
If `style` is a str, it is used as the path to a json file
which contains a style dict. The file will be opened, parsed, and
then any style elements in the dict will replace the default values
in the input dict. A file to be loaded must end in ``.json``, but
the name entered here can omit ``.json``. For example,
``style='iqx.json'`` or ``style='iqx'``.
If `style` is a dict and the ``'name'`` key is set, that name
will be used to load a json file, followed by loading the other
items in the style dict. For example, ``style={'name': 'iqx'}``.
If `style` is not a str and `name` is not a key in the style dict,
then the default value from the user config file (usually
``~/.qiskit/settings.conf``) will be used, for example,
``circuit_mpl_style = iqx``.
If none of these are set, the `default` style will be used.
The search path for style json files can be specified in the user
config, for example,
``circuit_mpl_style_path = /home/user/styles:/home/user``.
See: :class:`~qiskit.visualization.qcstyle.DefaultStyle` for more
information on the contents.
output (str): select the output method to use for drawing the circuit.
Valid choices are ``text``, ``mpl``, ``latex``, ``latex_source``.
By default, the `text` drawer is used unless the user config file
(usually ``~/.qiskit/settings.conf``) has an alternative backend set
as the default. For example, ``circuit_drawer = latex``. If the output
kwarg is set, that backend will always be used over the default in
the user config file.
interactive (bool): when set to true, show the circuit in a new window
(for `mpl` this depends on the matplotlib backend being used
supporting this). Note when used with either the `text` or the
`latex_source` output type this has no effect and will be silently
ignored. Defaults to False.
reverse_bits (bool): when set to True, reverse the bit order inside
registers for the output visualization. Defaults to False unless the
user config file (usually ``~/.qiskit/settings.conf``) has an
alternative value set. For example, ``circuit_reverse_bits = True``.
plot_barriers (bool): enable/disable drawing barriers in the output
circuit. Defaults to True.
justify (string): options are ``left``, ``right`` or ``none``. If
anything else is supplied, it defaults to left justified. It refers
to where gates should be placed in the output circuit if there is
an option. ``none`` results in each gate being placed in its own
column.
vertical_compression (string): ``high``, ``medium`` or ``low``. It
merges the lines generated by the `text` output so the drawing
will take less vertical room. Default is ``medium``. Only used by
the `text` output, will be silently ignored otherwise.
idle_wires (bool): include idle wires (wires with no circuit elements)
in output visualization. Default is True.
with_layout (bool): include layout information, with labels on the
physical layout. Default is True.
fold (int): sets pagination. It can be disabled using -1. In `text`,
sets the length of the lines. This is useful when the drawing does
not fit in the console. If None (default), it will try to guess the
console width using ``shutil.get_terminal_size()``. However, if
running in jupyter, the default line length is set to 80 characters.
In `mpl`, it is the number of (visual) layers before folding.
Default is 25.
ax (matplotlib.axes.Axes): Only used by the `mpl` backend. An optional
Axes object to be used for the visualization output. If none is
specified, a new matplotlib Figure will be created and used.
Additionally, if specified there will be no returned Figure since
it is redundant.
initial_state (bool): Optional. Adds ``|0>`` in the beginning of the wire.
Default is False.
cregbundle (bool): Optional. If set True, bundle classical registers into a single wire.
Default is true if possible, and false if a block instruction needs to access an
individual bit from a register.
wire_order (list): Optional. A list of integers used to reorder the display
of the bits. The list must have an entry for every bit with the bits
in the range 0 to (num_qubits + num_clbits).
Returns:
:class:`TextDrawing` or :class:`matplotlib.figure` or :class:`PIL.Image` or
:class:`str`:
* `TextDrawing` (output='text')
A drawing that can be printed as ascii art.
* `matplotlib.figure.Figure` (output='mpl')
A matplotlib figure object for the circuit diagram.
* `PIL.Image` (output='latex')
An in-memory representation of the image of the circuit diagram.
* `str` (output='latex_source')
The LaTeX source code for visualizing the circuit diagram.
Raises:
VisualizationError: when an invalid output method is selected
MissingOptionalLibraryError: when the output methods requires non-installed libraries.
Example:
.. plot::
:include-source:
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
from qiskit.tools.visualization import circuit_drawer
q = QuantumRegister(1)
c = ClassicalRegister(1)
qc = QuantumCircuit(q, c)
qc.h(q)
qc.measure(q, c)
circuit_drawer(qc, output='mpl', style={'backgroundcolor': '#EEEEEE'})
"""
image = None
config = user_config.get_config()
# Get default from config file else use text
default_output = "text"
default_reverse_bits = False
if config:
default_output = config.get("circuit_drawer", "text")
if default_output == "auto":
if _optionals.HAS_MATPLOTLIB:
default_output = "mpl"
else:
default_output = "text"
if wire_order is None:
default_reverse_bits = config.get("circuit_reverse_bits", False)
if output is None:
output = default_output
if reverse_bits is None:
reverse_bits = default_reverse_bits
if wire_order is not None and reverse_bits:
raise VisualizationError(
"The wire_order option cannot be set when the reverse_bits option is True."
)
complete_wire_order = wire_order
if wire_order is not None:
wire_order_len = len(wire_order)
total_wire_len = circuit.num_qubits + circuit.num_clbits
if wire_order_len not in [circuit.num_qubits, total_wire_len]:
raise VisualizationError(
f"The wire_order list (length {wire_order_len}) should as long as "
f"the number of qubits ({circuit.num_qubits}) or the "
f"total numbers of qubits and classical bits {total_wire_len}."
)
if len(set(wire_order)) != len(wire_order):
raise VisualizationError("The wire_order list should not have repeated elements.")
if wire_order_len == circuit.num_qubits:
complete_wire_order = wire_order + list(range(circuit.num_qubits, total_wire_len))
if (
circuit.clbits
and (reverse_bits or wire_order is not None)
and not set(wire_order or []).issubset(set(range(circuit.num_qubits)))
):
if cregbundle:
warn(
"cregbundle set to False since either reverse_bits or wire_order "
"(over classical bit) has been set.",
RuntimeWarning,
2,
)
cregbundle = False
if output == "text":
return _text_circuit_drawer(
circuit,
filename=filename,
reverse_bits=reverse_bits,
plot_barriers=plot_barriers,
justify=justify,
vertical_compression=vertical_compression,
idle_wires=idle_wires,
with_layout=with_layout,
fold=fold,
initial_state=initial_state,
cregbundle=cregbundle,
wire_order=complete_wire_order,
)
elif output == "latex":
image = _latex_circuit_drawer(
circuit,
filename=filename,
scale=scale,
style=style,
plot_barriers=plot_barriers,
reverse_bits=reverse_bits,
justify=justify,
idle_wires=idle_wires,
with_layout=with_layout,
initial_state=initial_state,
cregbundle=cregbundle,
wire_order=complete_wire_order,
)
elif output == "latex_source":
return _generate_latex_source(
circuit,
filename=filename,
scale=scale,
style=style,
plot_barriers=plot_barriers,
reverse_bits=reverse_bits,
justify=justify,
idle_wires=idle_wires,
with_layout=with_layout,
initial_state=initial_state,
cregbundle=cregbundle,
wire_order=complete_wire_order,
)
elif output == "mpl":
image = _matplotlib_circuit_drawer(
circuit,
scale=scale,
filename=filename,
style=style,
plot_barriers=plot_barriers,
reverse_bits=reverse_bits,
justify=justify,
idle_wires=idle_wires,
with_layout=with_layout,
fold=fold,
ax=ax,
initial_state=initial_state,
cregbundle=cregbundle,
wire_order=complete_wire_order,
)
else:
raise VisualizationError(
"Invalid output type %s selected. The only valid choices "
"are text, latex, latex_source, and mpl" % output
)
if image and interactive:
image.show()
return image
# -----------------------------------------------------------------------------
# _text_circuit_drawer
# -----------------------------------------------------------------------------
def _text_circuit_drawer(
circuit,
filename=None,
reverse_bits=False,
plot_barriers=True,
justify=None,
vertical_compression="high",
idle_wires=True,
with_layout=True,
fold=None,
initial_state=True,
cregbundle=None,
encoding=None,
wire_order=None,
):
"""Draws a circuit using ascii art.
Args:
circuit (QuantumCircuit): Input circuit
filename (str): Optional filename to write the result
reverse_bits (bool): Rearrange the bits in reverse order.
plot_barriers (bool): Draws the barriers when they are there.
justify (str) : `left`, `right` or `none`. Defaults to `left`. Says how
the circuit should be justified.
vertical_compression (string): `high`, `medium`, or `low`. It merges the
lines so the drawing will take less vertical room. Default is `high`.
idle_wires (bool): Include idle wires. Default is True.
with_layout (bool): Include layout information with labels on the physical
layout. Default: True
fold (int): Optional. Breaks the circuit drawing to this length. This
is useful when the drawing does not fit in the console. If
None (default), it will try to guess the console width using
`shutil.get_terminal_size()`. If you don't want pagination
at all, set `fold=-1`.
initial_state (bool): Optional. Adds |0> in the beginning of the line.
Default: `False`.
cregbundle (bool): Optional. If set True, bundle classical registers.
Default: ``True``.
encoding (str): Optional. Sets the encoding preference of the output.
Default: ``sys.stdout.encoding``.
wire_order (list): Optional. A list of integers used to reorder the display
of the bits. The list must have an entry for every bit with the bits
in the range 0 to (num_qubits + num_clbits).
Returns:
TextDrawing: An instance that, when printed, draws the circuit in ascii art.
Raises:
VisualizationError: When the filename extension is not .txt.
"""
qubits, clbits, nodes = _utils._get_layered_instructions(
circuit,
reverse_bits=reverse_bits,
justify=justify,
idle_wires=idle_wires,
wire_order=wire_order,
)
text_drawing = _text.TextDrawing(
qubits,
clbits,
nodes,
circuit,
reverse_bits=reverse_bits,
initial_state=initial_state,
cregbundle=cregbundle,
encoding=encoding,
with_layout=with_layout,
)
text_drawing.plotbarriers = plot_barriers
text_drawing.line_length = fold
text_drawing.vertical_compression = vertical_compression
if filename:
text_drawing.dump(filename, encoding=encoding)
return text_drawing
# -----------------------------------------------------------------------------
# latex_circuit_drawer
# -----------------------------------------------------------------------------
@_optionals.HAS_PDFLATEX.require_in_call("LaTeX circuit drawing")
@_optionals.HAS_PDFTOCAIRO.require_in_call("LaTeX circuit drawing")
@_optionals.HAS_PIL.require_in_call("LaTeX circuit drawing")
def _latex_circuit_drawer(
circuit,
scale=0.7,
style=None,
filename=None,
plot_barriers=True,
reverse_bits=False,
justify=None,
idle_wires=True,
with_layout=True,
initial_state=False,
cregbundle=None,
wire_order=None,
):
"""Draw a quantum circuit based on latex (Qcircuit package)
Requires version >=2.6.0 of the qcircuit LaTeX package.
Args:
circuit (QuantumCircuit): a quantum circuit
scale (float): scaling factor
style (dict or str): dictionary of style or file name of style file
filename (str): file path to save image to
reverse_bits (bool): When set to True reverse the bit order inside
registers for the output visualization.
plot_barriers (bool): Enable/disable drawing barriers in the output
circuit. Defaults to True.
justify (str) : `left`, `right` or `none`. Defaults to `left`. Says how
the circuit should be justified.
idle_wires (bool): Include idle wires. Default is True.
with_layout (bool): Include layout information, with labels on the physical
layout. Default: True
initial_state (bool): Optional. Adds |0> in the beginning of the line.
Default: `False`.
cregbundle (bool): Optional. If set True, bundle classical registers. On by default, if
this is possible for the given circuit, otherwise off.
wire_order (list): Optional. A list of integers used to reorder the display
of the bits. The list must have an entry for every bit with the bits
in the range 0 to (num_qubits + num_clbits).
Returns:
PIL.Image: an in-memory representation of the circuit diagram
Raises:
MissingOptionalLibraryError: if pillow, pdflatex, or poppler are not installed
VisualizationError: if one of the conversion utilities failed for some internal or
file-access reason.
"""
from PIL import Image
tmpfilename = "circuit"
with tempfile.TemporaryDirectory() as tmpdirname:
tmppath = os.path.join(tmpdirname, tmpfilename + ".tex")
_generate_latex_source(
circuit,
filename=tmppath,
scale=scale,
style=style,
plot_barriers=plot_barriers,
reverse_bits=reverse_bits,
justify=justify,
idle_wires=idle_wires,
with_layout=with_layout,
initial_state=initial_state,
cregbundle=cregbundle,
wire_order=wire_order,
)
try:
subprocess.run(
[
"pdflatex",
"-halt-on-error",
f"-output-directory={tmpdirname}",
f"{tmpfilename + '.tex'}",
],
stdout=subprocess.PIPE,
stderr=subprocess.DEVNULL,
check=True,
)
except OSError as exc:
# OSError should generally not occur, because it's usually only triggered if `pdflatex`
# doesn't exist as a command, but we've already checked that.
raise VisualizationError("`pdflatex` command could not be run.") from exc
except subprocess.CalledProcessError as exc:
with open("latex_error.log", "wb") as error_file:
error_file.write(exc.stdout)
logger.warning(
"Unable to compile LaTeX. Perhaps you are missing the `qcircuit` package."
" The output from the `pdflatex` command is in `latex_error.log`."
)
raise VisualizationError(
"`pdflatex` call did not succeed: see `latex_error.log`."
) from exc
base = os.path.join(tmpdirname, tmpfilename)
try:
subprocess.run(
["pdftocairo", "-singlefile", "-png", "-q", base + ".pdf", base],
check=True,
)
except (OSError, subprocess.CalledProcessError) as exc:
message = "`pdftocairo` failed to produce an image."
logger.warning(message)
raise VisualizationError(message) from exc
image = Image.open(base + ".png")
image = trim_image(image)
if filename:
if filename.endswith(".pdf"):
shutil.move(base + ".pdf", filename)
else:
try:
image.save(filename)
except (ValueError, OSError) as exc:
raise VisualizationError(
f"Pillow could not write the image file '{filename}'."
) from exc
return image
def _generate_latex_source(
circuit,
filename=None,
scale=0.7,
style=None,
reverse_bits=False,
plot_barriers=True,
justify=None,
idle_wires=True,
with_layout=True,
initial_state=False,
cregbundle=None,
wire_order=None,
):
"""Convert QuantumCircuit to LaTeX string.
Args:
circuit (QuantumCircuit): a quantum circuit
scale (float): scaling factor
style (dict or str): dictionary of style or file name of style file
filename (str): optional filename to write latex
reverse_bits (bool): When set to True reverse the bit order inside
registers for the output visualization.
plot_barriers (bool): Enable/disable drawing barriers in the output
circuit. Defaults to True.
justify (str) : `left`, `right` or `none`. Defaults to `left`. Says how
the circuit should be justified.
idle_wires (bool): Include idle wires. Default is True.
with_layout (bool): Include layout information, with labels on the physical
layout. Default: True
initial_state (bool): Optional. Adds |0> in the beginning of the line.
Default: `False`.
cregbundle (bool): Optional. If set True, bundle classical registers.
wire_order (list): Optional. A list of integers used to reorder the display
of the bits. The list must have an entry for every bit with the bits
in the range 0 to (num_qubits + num_clbits).
Returns:
str: Latex string appropriate for writing to file.
"""
qubits, clbits, nodes = _utils._get_layered_instructions(
circuit,
reverse_bits=reverse_bits,
justify=justify,
idle_wires=idle_wires,
wire_order=wire_order,
)
qcimg = _latex.QCircuitImage(
qubits,
clbits,
nodes,
scale,
style=style,
reverse_bits=reverse_bits,
plot_barriers=plot_barriers,
initial_state=initial_state,
cregbundle=cregbundle,
with_layout=with_layout,
circuit=circuit,
)
latex = qcimg.latex()
if filename:
with open(filename, "w") as latex_file:
latex_file.write(latex)
return latex
# -----------------------------------------------------------------------------
# matplotlib_circuit_drawer
# -----------------------------------------------------------------------------
def _matplotlib_circuit_drawer(
circuit,
scale=None,
filename=None,
style=None,
plot_barriers=True,
reverse_bits=False,
justify=None,
idle_wires=True,
with_layout=True,
fold=None,
ax=None,
initial_state=False,
cregbundle=None,
wire_order=None,
):
"""Draw a quantum circuit based on matplotlib.
If `%matplotlib inline` is invoked in a Jupyter notebook, it visualizes a circuit inline.
We recommend `%config InlineBackend.figure_format = 'svg'` for the inline visualization.
Args:
circuit (QuantumCircuit): a quantum circuit
scale (float): scaling factor
filename (str): file path to save image to
style (dict or str): dictionary of style or file name of style file
reverse_bits (bool): When set to True, reverse the bit order inside
registers for the output visualization.
plot_barriers (bool): Enable/disable drawing barriers in the output
circuit. Defaults to True.
justify (str): `left`, `right` or `none`. Defaults to `left`. Says how
the circuit should be justified.
idle_wires (bool): Include idle wires. Default is True.
with_layout (bool): Include layout information, with labels on the physical
layout. Default: True.
fold (int): Number of vertical layers allowed before folding. Default is 25.
ax (matplotlib.axes.Axes): An optional Axes object to be used for
the visualization output. If none is specified, a new matplotlib
Figure will be created and used. Additionally, if specified there
will be no returned Figure since it is redundant.
initial_state (bool): Optional. Adds |0> in the beginning of the line.
Default: `False`.
cregbundle (bool): Optional. If set True bundle classical registers.
Default: ``True``.
wire_order (list): Optional. A list of integers used to reorder the display
of the bits. The list must have an entry for every bit with the bits
in the range 0 to (num_qubits + num_clbits).
Returns:
matplotlib.figure: a matplotlib figure object for the circuit diagram
if the ``ax`` kwarg is not set.
"""
qubits, clbits, nodes = _utils._get_layered_instructions(
circuit,
reverse_bits=reverse_bits,
justify=justify,
idle_wires=idle_wires,
wire_order=wire_order,
)
if fold is None:
fold = 25
qcd = _matplotlib.MatplotlibDrawer(
qubits,
clbits,
nodes,
circuit,
scale=scale,
style=style,
reverse_bits=reverse_bits,
plot_barriers=plot_barriers,
fold=fold,
ax=ax,
initial_state=initial_state,
cregbundle=cregbundle,
with_layout=with_layout,
)
return qcd.draw(filename)