Chapter 3: shortest path has changed?

[AllenDowney]

Submitted by a reader:

Think Complexity version 2.6.3

This example from chapter 3 in the book expects a mean path length of 1, but with networkx version 3.4.1, the function returns 0.666.

Book:
"And we can test it with a small ring lattice:

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In this example, all 3 nodes are connected to each other, so the mean path length is 1."

Notebook:

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I modified the functions to investigate and see that a path length of 0 is being returned for the distance from a node to itself. Maybe the way shortest_path_length works changed?

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