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"""
========
Simplify
========
This example shows how to remove self loops and multiple edges using :meth:`igraph.GraphBase.simplify`.
"""
import igraph as ig
import matplotlib.pyplot as plt
# %%
# We start with a graph that includes loops and multiedges:
g1 = ig.Graph([
(0, 1),
(1, 2),
(2, 3),
(3, 4),
(4, 0),
(0, 0),
(1, 4),
(1, 4),
(0, 2),
(2, 4),
(2, 4),
(2, 4),
(3, 3)],
)
# %%
# To simplify the graph, we must remember that the function operates in place,
# i.e. directly changes the graph that it is run on. So we need to first make a
# copy of our graph, and then simplify that copy to keep the original graph
# untouched:
g2 = g1.copy()
g2.simplify()
# %%
# We can then proceed to plot both graphs to see the difference. First, let's
# choose a consistent visual style:
visual_style = {
"vertex_color": "lightblue",
"vertex_size": 20,
"vertex_label": [0, 1, 2, 3, 4],
}
# %%
# And finally, let's plot them in twin axes, with rectangular frames around
# each plot:
fig, axs = plt.subplots(1, 2, sharex=True, sharey=True)
ig.plot(
g1,
layout="circle",
target=axs[0],
**visual_style,
)
ig.plot(
g2,
layout="circle",
target=axs[1],
**visual_style,
)
axs[0].set_title('Multigraph...')
axs[1].set_title('...simplified')
# Draw rectangles around axes
axs[0].add_patch(plt.Rectangle(
(0, 0), 1, 1, fc='none', ec='k', lw=4, transform=axs[0].transAxes,
))
axs[1].add_patch(plt.Rectangle(
(0, 0), 1, 1, fc='none', ec='k', lw=4, transform=axs[1].transAxes,
))
plt.show()
|
