Use this if you are using igraph from R
These functions find all, the largest or all the maximal cliques in an undirected graph. The size of the largest clique can also be calculated.
cliques(graph, min = NULL, max = NULL) max_cliques(graph, min = NULL, max = NULL, subset = NULL, file = NULL)
graph 
The input graph, directed graphs will be considered as undirected ones, multiple edges and loops are ignored. 
min 
Numeric constant, lower limit on the size of the cliques to find.

max 
Numeric constant, upper limit on the size of the cliques to find.

subset 
If not 
file 
If not 
cliques
find all complete subgraphs in the input graph, obeying the
size limitations given in the min
and max
arguments.
largest_cliques
finds all largest cliques in the input graph. A
clique is largest if there is no other clique including more vertices.
max_cliques
finds all maximal cliques in the input graph. A
clique in maximal if it cannot be extended to a larger clique. The largest
cliques are always maximal, but a maximal clique is not necessarily the
largest.
count_max_cliques
counts the maximal cliques.
clique_num
calculates the size of the largest clique(s).
The current implementation of these functions searches for maximal
independent vertex sets (see ivs
) in the
complementer graph.
cliques
, largest_cliques
and clique_num
return a list containing numeric vectors of vertex ids. Each list element is
a clique, i.e. a vertex sequence of class igraph.vs
.
max_cliques
returns NULL
, invisibly, if its file
argument is not NULL
. The output is written to the specified file in
this case.
clique_num
and count_max_cliques
return an integer
scalar.
Tamas Nepusz ntamas@gmail.com and Gabor Csardi csardi.gabor@gmail.com
For maximal cliques the following algorithm is implemented: David Eppstein, Maarten Loffler, Darren Strash: Listing All Maximal Cliques in Sparse Graphs in Nearoptimal Time. https://arxiv.org/abs/1006.5440
# this usually contains cliques of size six g < sample_gnp(100, 0.3) clique_num(g) cliques(g, min=6) largest_cliques(g) # To have a bit less maximal cliques, about 100200 usually g < sample_gnp(100, 0.03) max_cliques(g)