qiskit.visualization.dag_drawer

qiskit.visualization.dag_drawer(dag, scale=0.7, filename=None, style='color')

Plot the directed acyclic graph (dag) to represent operation dependencies in a quantum circuit.

This function calls the graphviz_draw() function from the rustworkx package to draw the DAG.

Parameters

• dag (DAGCircuit orDAGDependency) – The dag to draw.

• scale (float) – scaling factor

• filename (str) – file path to save image to (format inferred from name)

• style (dict orstr) –

  Style name, file name of style JSON file, or a dictionary specifying the style.

  • The supported style names are ‘plain’: B&W graph, ‘color’ (default):

    (color input/output/op nodes)

  • If given a JSON file, e.g. my_style.json or my_style (the .json

    extension may be omitted), this function attempts to load the style dictionary from that location. Note, that the JSON file must completely specify the visualization specifications. The file is searched for in qiskit/visualization/circuit/styles, the current working directory, and the location specified in ~/.qiskit/settings.conf.

  • If None the default style "color" is used or, if given, the default style

    specified in ~/.qiskit/settings.conf.

Returns

if in Jupyter notebook and not saving to file,

otherwise None.

Return type

PIL.Image

Raises

• VisualizationError – when style is not recognized.
• InvalidFileError – when filename provided is not valid
• ValueError – If the file extension for filename is not an image type supported by Graphviz.

Example

from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
from qiskit.converters import circuit_to_dag
from qiskit.visualization import dag_drawer

q = QuantumRegister(3, 'q')
c = ClassicalRegister(3, 'c')
circ = QuantumCircuit(q, c)
circ.h(q[0])
circ.cx(q[0], q[1])
circ.measure(q[0], c[0])
with circ.if_test((c, 2)):
    circ.rz(0.5, q[1])

dag = circuit_to_dag(circ)

style = {
    "inputnodecolor": "pink",
    "outputnodecolor": "lightblue",
    "opnodecolor": "red",
}

dag_drawer(dag, style=style)