# graph-clique: Get cliques of an undirected graph In gRbase: A Package for Graphical Modelling in R

 graph-clique R Documentation

## Get cliques of an undirected graph

### Description

Return a list of (maximal) cliques of an undirected graph.

### Usage

```get_cliques(object)

max_cliqueMAT(amat)

getCliques(object)

maxCliqueMAT(amat)
```

### Arguments

 `object` An undirected graph represented either as a `graphNEL` object, an `igraph` object, a (dense) `matrix`, a (sparse) `dgCMatrix` `amat` An adjacency matrix.

### Details

In graph theory, a clique is often a complete subset of a graph. A maximal clique is a clique which can not be enlarged. In statistics (and that is the convention we follow here) a clique is usually understood to be a maximal clique.

Finding the cliques of a general graph is an NP complete problem. Finding the cliques of triangualted graph is linear in the number of cliques.

The workhorse is the `max_cliqueMAT` function which calls the `maxClique` function in the `RBGL` package.

A list.

### Synonymous functions

For backward compatibility with downstream packages we have the following synonymous functions:

• getCliques = get_cliques

• maxCliqueMAT = max_cliqueMAT

### Author(s)

Søren Højsgaard, sorenh@math.aau.dk

`ug`, `dag`, `mcs`, `mcsMAT`, `rip`, `ripMAT`, `moralize`, `moralizeMAT`

### Examples

```## graphNEL
uG0 <- ug(~a:b + b:c + c:d + d:e + e:f + f:a) # a graphNEL object
get_cliques(uG0)

uG1 <- as(uG0, "igraph")
get_cliques(uG1)

uG2 <- as(uG0, "matrix")
get_cliques(uG2)

uG3 <- as(uG1, "dgCMatrix")
get_cliques(uG3)
```

gRbase documentation built on April 2, 2022, 5:06 p.m.