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Graph density

As explained in Knowledge Graphs and LLMs in Action

Graph density is the fraction of possible edges that are present between nodes in a graph or subgraph.

Graph density measures the fraction of possible edges that actually occur. For an undirected graph with N nodes and M edges, density is M divided by N(N−1)/2, producing a value from 0 to 1. section 4.2.3 section 10.1.3

Use density to assess how tightly connected a graph or subgraph is. Disease pathways in a protein–protein interaction network had a median density of 0.07, indicating limited internal connectivity. section 4.2.3 section 4.5

Computing pathway density

A NetworkX implementation counts nodes and edges, then calculates 2M/[N(N−1)]. For a node-level measure, construct its egonet, count observed edges, divide by N(N−1)/2, and handle egonets with fewer than two nodes.

How Knowledge Graphs and LLMs in Action covers it

How deep it goes
Defines the metric, gives formulas, interprets distributions, and demonstrates Python calculation without deriving advanced graph theory.
Examples
Uses disease pathways in protein-interaction networks and node egonets in a fraud-detection graph, including tabulated node values.
What it assumes
Assumes basic graphs, nodes, edges, and Python familiarity while defining possible-edge counting from zero.
What you can do after
Compute density for whole graphs, disease subgraphs, or node egonets and interpret high or low connectivity.
How it connects
Connects graph density with subgraph analysis, conductance, connected components, clustering, knowledge graphs, and egonets.

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Related concepts

This explainer was generated by Manning's knowledge graph from the text of Knowledge Graphs and LLMs in Action. The section links point to the parts of the book it draws on.