# betweenness: Vertex and edge betweenness centrality In igraph: Network Analysis and Visualization

 betweenness R Documentation

## Vertex and edge betweenness centrality

### Description

The vertex and edge betweenness are (roughly) defined by the number of geodesics (shortest paths) going through a vertex or an edge.

### Usage

betweenness(
graph,
v = V(graph),
directed = TRUE,
weights = NULL,
nobigint = TRUE,
normalized = FALSE,
cutoff = -1
)

edge_betweenness(
graph,
e = E(graph),
directed = TRUE,
weights = NULL,
cutoff = -1
)


### Arguments

 graph The graph to analyze. v The vertices for which the vertex betweenness will be calculated. directed Logical, whether directed paths should be considered while determining the shortest paths. weights Optional positive weight vector for calculating weighted betweenness. If the graph has a weight edge attribute, then this is used by default. Weights are used to calculate weighted shortest paths, so they are interpreted as distances. nobigint Logical scalar, whether to use big integers during the calculation. Deprecated since igraph 1.3 and will be removed in igraph 1.4. normalized Logical scalar, whether to normalize the betweenness scores. If TRUE, then the results are normalized by the number of ordered or unordered vertex pairs in directed and undirected graphs, respectively. In an undirected graph, B^n=\frac{2B}{(n-1)(n-2)}, where B^n is the normalized, B the raw betweenness, and n is the number of vertices in the graph. cutoff The maximum path length to consider when calculating the betweenness. If zero or negative then there is no such limit. e The edges for which the edge betweenness will be calculated.

### Details

The vertex betweenness of vertex v is defined by

\sum_{i\ne j, i\ne v, j\ne v} g_{ivj}/g_{ij}

The edge betweenness of edge e is defined by

\sum_{i\ne j} g_{iej}/g_{ij}.

betweenness() calculates vertex betweenness, edge_betweenness() calculates edge betweenness.

Here g_{ij} is the total number of shortest paths between vertices i and j while g_{ivj} is the number of those shortest paths which pass though vertex v.

Both functions allow you to consider only paths of length cutoff or smaller; this can be run for larger graphs, as the running time is not quadratic (if cutoff is small). If cutoff is zero or negative, then the function calculates the exact betweenness scores. Using zero as a cutoff is deprecated and future versions (from 1.4.0) will treat zero cutoff literally (i.e. no paths considered at all). If you want no cutoff, use a negative number.

For calculating the betweenness a similar algorithm to the one proposed by Brandes (see References) is used.

### Value

A numeric vector with the betweenness score for each vertex in v for betweenness().

A numeric vector with the edge betweenness score for each edge in e for edge_betweenness().

### Note

edge_betweenness() might give false values for graphs with multiple edges.

### Author(s)

Gabor Csardi csardi.gabor@gmail.com

### References

Freeman, L.C. (1979). Centrality in Social Networks I: Conceptual Clarification. Social Networks, 1, 215-239.

Ulrik Brandes, A Faster Algorithm for Betweenness Centrality. Journal of Mathematical Sociology 25(2):163-177, 2001.

closeness(), degree(), harmonic_centrality()

Centrality measures alpha_centrality(), closeness(), diversity(), eigen_centrality(), harmonic_centrality(), hub_score(), page_rank(), power_centrality(), spectrum(), strength(), subgraph_centrality()

Centrality measures alpha_centrality(), closeness(), diversity(), eigen_centrality(), harmonic_centrality(), hub_score(), page_rank(), power_centrality(), spectrum(), strength(), subgraph_centrality()

### Examples


g <- sample_gnp(10, 3 / 10)
betweenness(g)
edge_betweenness(g)



igraph documentation built on Aug. 10, 2023, 9:08 a.m.