Cliques ¶
Cliques¶
This example shows how to compute and visualize cliques of a graph using cliques()
.
import igraph as ig
import matplotlib.pyplot as plt
g = ig.Graph.Famous('Zachary')
# Compute cliques
cliques = g.cliques(4, 4)
# Plot each clique highlighted in a separate axes
fig, axs = plt.subplots(3, 4)
axs = axs.ravel()
for clique, ax in zip(cliques, axs):
ig.plot(
ig.VertexCover(g, [clique]),
mark_groups=True, palette=ig.RainbowPalette(),
edge_width=0.5,
target=ax,
)
plt.axis('off')
plt.show()
The plot looks like this:

Each clique of the graph is highlighted in one of the panels¶
Advanced: improving plotting style¶
If you want a little more style, you can color the vertices/edges within each clique to make them stand out:
import igraph as ig
import matplotlib.pyplot as plt
g = ig.Graph.Famous('Zachary')
cliques = g.cliques(4, 4)
fig, axs = plt.subplots(3, 4)
axs = axs.ravel()
for clique, ax in zip(cliques, axs):
# Color vertices yellow/red based on whether they are in this clique
g.vs['color'] = 'yellow'
g.vs[clique]['color'] = 'red'
# Color edges black/red based on whether they are in this clique
clique_edges = g.es.select(_within=clique)
g.es['color'] = 'black'
clique_edges['color'] = 'red'
# also increase thickness of clique edges
g.es['width'] = 0.3
clique_edges['width'] = 1
ig.plot(
ig.VertexCover(g, [clique]),
mark_groups=True,
palette=ig.RainbowPalette(),
target=ax,
)
plt.axis('off')
plt.show()
Lo and behold:

Each clique of the graph is highlighted in one of the panels, with vertices and edges highlighted as well.¶