how do I draw selfloops using Networkx and matplotlib in Python

Question

I am using networkx and trying to find cycles in graphs. I wrote the following code:

import networkx as nx
import matplotlib.pyplot as plt
import pylab

tg = nx.Graph()

h_lat_dir = {1: [("A", "A"), ("B", "B"), ("A", "B")], 2: [("C", "D")],
    3: [("C", "F")], 4: [("F", "F")], 5: [("C", "C"), ("C", "E"), ("D", "E"), ("E", "E")],
    6: [("D", "D")]}

for wght, edgelist in h_lat_dir.iteritems():
    tg.add_edges_from(edgelist, weight=wght)

print nx.cycle_basis(tg)


nx.write_dot(tg, 'multi.dot')
nx.draw_graphviz(tg)
pylab.show()

the result is

[['A'], ['B'], ['C'], ['F'], ['E', 'D', 'C'], ['D'], ['E']]

and this drawing enter image description here

Why can't I see the self_loops? (every vertex has one) Is it possible to draw them somehow?

If you can use graphviz here is an approach (requires pygraphviz or pydot) stackoverflow.com/questions/22312334/… — Aric
– Aric, Commented May 25, 2014 at 22:28
The example you provided works on Digraph. Mine is undirected. — Yannis
– Yannis, Commented May 26, 2014 at 7:00

Aric · Accepted Answer · 2014-05-26 11:47:43Z

2

Using the NetworkX interface to Graphviz (through pygraphviz or pydot):

import networkx as nx
import matplotlib.pyplot as plt

G = nx.Graph()
G.add_edges_from([(0,1), (0,2), (1,1), (1,2)])
nx.write_dot(G,'graph.dot')

Then run

dot -Tpng graph.dot > graph.png

enter image description here

answered May 26, 2014 at 11:47

Aric

25.4k6 gold badges83 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Yannis Over a year ago

I copy paste your code, run the command and still get a directed - no self looped graph ???

Aric Over a year ago

Could you show the output dot file and associated drawing?

Yannis Over a year ago

graph.dot: strict digraph { 0 -> 1; 0 -> 2; 1 -> 2; } and the image (how can I upload it here???) is like yours with directed edges 0->1 0->2 1->2 and no edge 1->1

Aric Over a year ago

It seems there is something wrong with the pygraphviz or pydot (not sure which one you are using) installation. If you use nx.Graph() and send that to nx.write_dot() you should get a graph not a digraph in the dot output.

Dan M. Over a year ago

Sad that it is still not possible to do many years after =( I was hoping that networkx was the tool to switch from graphviz, I want to have some easy way to interactively draw graphs based on adj matrix and generating dot and processingt it with graphviz is a no-go.

Collectives™ on Stack Overflow

how do I draw selfloops using Networkx and matplotlib in Python

1 Answer 1

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related