Remove advanced example section (#4429)

1 files changed, 22 insertions, 0 deletions

diff --git a/examples/drawing/plot_eigenvalues.py b/examples/drawing/plot_eigenvalues.py
new file mode 100644
index 00000000..b0df67ae
--- /dev/null
+++ b/examples/drawing/plot_eigenvalues.py
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+"""
+===========
+Eigenvalues
+===========
+
+Create an G{n,m} random graph and compute the eigenvalues.
+"""
+import matplotlib.pyplot as plt
+import networkx as nx
+import numpy.linalg
+
+n = 1000  # 1000 nodes
+m = 5000  # 5000 edges
+G = nx.gnm_random_graph(n, m, seed=5040)  # Seed for reproducibility
+
+L = nx.normalized_laplacian_matrix(G)
+e = numpy.linalg.eigvals(L.A)
+print("Largest eigenvalue:", max(e))
+print("Smallest eigenvalue:", min(e))
+plt.hist(e, bins=100)  # histogram with 100 bins
+plt.xlim(0, 2)  # eigenvalues between 0 and 2
+plt.show()