# R igraph manual pages

Use this if you are using igraph from R

 edge_density {igraph} R Documentation

## Graph density

### Description

The density of a graph is the ratio of the number of edges and the number of possible edges.

### Usage

edge_density(graph, loops = FALSE)


### Arguments

 graph The input graph. loops Logical constant, whether to allow loop edges in the graph. If this is TRUE then self loops are considered to be possible. If this is FALSE then we assume that the graph does not contain any loop edges and that loop edges are not meaningful.

### Details

Note that this function may return strange results for graph with multiple edges, density is ill-defined for graphs with multiple edges.

### Value

A real constant. This function returns NaN (=0.0/0.0) for an empty graph with zero vertices.

### Author(s)

Gabor Csardi csardi.gabor@gmail.com

### References

Wasserman, S., and Faust, K. (1994). Social Network Analysis: Methods and Applications. Cambridge: Cambridge University Press.

vcount, ecount, simplify to get rid of the multiple and/or loop edges.

### Examples


g1 <- make_empty_graph(n=10)
g2 <- make_full_graph(n=10)
g3 <- sample_gnp(n=10, 0.4)

# loop edges
g <- graph( c(1,2, 2,2, 2,3) )
edge_density(g, loops=FALSE)              # this is wrong!!!
edge_density(g, loops=TRUE)               # this is right!!!
edge_density(simplify(g), loops=FALSE)    # this is also right, but different



[Package igraph version 1.3.5 Index]