AttributeError: 'DummyVertex' object has no attribute 'data'

[alabamagan]

Reproducing Example:

import networkx as nx
import matplotlib.pyplot as plt
from netgraph import Graph

G = nx.DiGraph()
G.add_nodes_from([0, 1, 2, 3, 4])
G.add_edges_from([(0, 1),
                  (1, 2),
                  (0, 2),
                  (1, 3),
                  (3, 4)])
Graph(graph=G, arrows=True, node_layout='dot', node_labels=True,
      node_label_fontdict={'size':14}, node_label_offset=0.1)
plt.show()

This results in error:
AttributeError: 'DummyVertex' object has no attribute 'data'

My package versions are:

networkx=2.6.2
netgraph=4.0.4
grandalf=0.7

Possible fix:
_node_layout.py:588

    # extract node positions
    node_positions = dict()
    for v in graph.C[0].sV:
        node_positions[v.data] = v.view.xy
    # for layer in layout.layers:
    #     for vertex in layer:
    #         node_positions[vertex.data] = vertex.view.xy

[paulbrodersen]

Hi, thanks for raising the issue with a brilliant MWE. I had never seen a DummyVertex object before today. From the grandalf documentation:

The DummyVertex class is used by the sugiyama layout to represent
long edges, i.e. edges that span over several ranks.
For these edges, a DummyVertex is inserted in every inner layer.

I adopted a slightly different solution but the issue should be solved in the latest version on github, and I will push a new version to PyPI presently.

Again, thank you very much and have a great week!