R: Symmetrize an Adjacency Matrix

symmetrize {sna} | R Documentation

## Symmetrize an Adjacency Matrix

### Description

Symmetrizes the elements of `mats` according to the rule in `rule`.

### Usage

    symmetrize(mats, rule="weak", return.as.edgelist=FALSE)

### Arguments

`mats` | a graph or graph stack.
`rule` | one of “upper”, “lower”, “strong” or “weak”.
`return.as.edgelist` | logical; should the symmetrized graphs be returned in edgelist form?

### Details

The rules used by `symmetrize` are as follows:

1. upper: Copy the upper triangle over the lower triangle

2. lower: Copy the lower triangle over the upper triangle

3. strong: i<->j iff i->j and i<-j (AND rule)

4. weak: i<->j iff i->j or i<-j (OR rule)

### Value

The symmetrized graph stack

### 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

    #Generate a graph
    g<-rgraph(5)

    #Weak symmetrization
    symmetrize(g)

    #Strong symmetrization
    symmetrize(g,rule="strong")

[Package sna version 2.6 Index]