R: Find the Density of a Graph

gden {sna} | R Documentation

## Find the Density of a Graph

### Description

`gden` computes the density of the graphs indicated by `g` in collection `dat`, adjusting for the type of graph in question.

### Usage

    gden(dat, g=NULL, diag=FALSE, mode="digraph", ignore.eval=FALSE)

### Arguments

`dat` | one or more input graphs.
`g` | integer indicating the index of the graphs for which the density is to be calculated (or a vector thereof). If `g==NULL` (the default), density is calculated for all graphs in `dat`.
`diag` | boolean indicating whether or not the diagonal should be treated as valid data. Set this true if and only if the data can contain loops. `diag` is `FALSE` by default.
`mode` | string indicating the type of graph being evaluated. "digraph" indicates that edges should be interpreted as directed; "graph" indicates that edges are undirected. `mode` is set to "digraph" by default.
`ignore.eval` | logical; should edge values be ignored when calculating density?

### Details

The density of a graph is here taken to be the sum of tie values divided by the number of possible ties (i.e., an unbiased estimator of the graph mean); hence, the result is interpretable for valued graphs as the mean tie value when `ignore.eval==FALSE`. The number of possible ties is determined by the graph type (and by `diag`) in the usual fashion.

Where missing data is present, it is removed prior to calculation. The density/graph mean is thus taken relative to the observed portion of the graph.

### Value

The graph density

### Author(s)

Carter T. Butts buttsc@uci.edu

### References

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

### Examples

    #Draw three random graphs
    dat<-rgraph(10,3)
    #Find their densities
    gden(dat)

[Package sna version 2.6 Index]