qiskit-documentation/docs/api/qiskit/0.39/qiskit.visualization.dag_dr...

62 lines
2.0 KiB
Plaintext
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

---
title: dag_drawer
description: API reference for qiskit.visualization.dag_drawer
in_page_toc_min_heading_level: 1
python_api_type: function
python_api_name: qiskit.visualization.dag_drawer
---
# qiskit.visualization.dag\_drawer
<Function id="qiskit.visualization.dag_drawer" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.22/qiskit/visualization/dag_visualization.py" signature="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 `retworkx` package to draw the DAG.
**Parameters**
* **dag** ([*DAGCircuit*](qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit")) The dag to draw.
* **scale** (*float*) scaling factor
* **filename** (*str*) file path to save image to (format inferred from name)
* **style** (*str*) plain: B\&W graph color (default): color input/output/op nodes
**Returns**
**if in Jupyter notebook and not saving to file,**
otherwise None.
**Return type**
PIL.Image
**Raises**
* [**VisualizationError**](qiskit.visualization.VisualizationError "qiskit.visualization.VisualizationError") when style is not recognized.
* **InvalidFileError** when filename provided is not valid
**Example**
```python
%matplotlib inline
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
from qiskit.dagcircuit import DAGCircuit
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])
circ.rz(0.5, q[1]).c_if(c, 2)
dag = circuit_to_dag(circ)
dag_drawer(dag)
```
![../\_images/qiskit.visualization.dag\_drawer\_0\_0.png](/images/api/qiskit/0.39/qiskit.visualization.dag_drawer_0_0.png)
</Function>