# diversity

0th

Percentile

##### Graph diversity

Calculates a measure of diversity for all vertices.

Keywords
graphs
##### Usage
diversity(graph, weights = NULL, vids = V(graph))
##### Arguments
graph

The input graph. Edge directions are ignored.

weights

NULL, or the vector of edge weights to use for the computation. If NULL, then the ‘weight’ attibute is used. Note that this measure is not defined for unweighted graphs.

vids

The vertex ids for which to calculate the measure.

##### Details

The diversity of a vertex is defined as the (scaled) Shannon entropy of the weights of its incident edges: $$D(i)=\frac{H(i)}{\log k_i}$$ and $$H(i)=-\sum_{j=1}^{k_i} p_{ij}\log p_{ij},$$ where $$p_{ij}=\frac{w_{ij}}{\sum_{l=1}^{k_i}}V_{il},$$ and $$k_i$$ is the (total) degree of vertex $$i$$, $$w_{ij}$$ is the weight of the edge(s) between vertices $$i$$ and $$j$$.

For vertices with degree less than two the function returns NaN.

##### Value

A numeric vector, its length is the number of vertices.

##### References

Nathan Eagle, Michael Macy and Rob Claxton: Network Diversity and Economic Development, Science 328, 1029--1031, 2010.

##### Aliases
• diversity
• graph.diversity
##### Examples
# NOT RUN {
g1 <- sample_gnp(20, 2/20)
g2 <- sample_gnp(20, 2/20)
g3 <- sample_gnp(20, 5/20)
E(g1)$weight <- 1 E(g2)$weight <- runif(ecount(g2))
E(g3)\$weight <- runif(ecount(g3))
diversity(g1)
diversity(g2)
diversity(g3)
# }

Documentation reproduced from package igraph, version 1.2.2, License: GPL (>= 2)

### Community examples

Looks like there are no examples yet.