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Detect Communities in a Network

Source: R/network-utils.R
detect_communities.Rd

Detects communities (clusters) in a network using various community detection algorithms. Returns a data frame with node-community assignments.

Usage

detect_communities(x, method = "louvain", directed = NULL, weights = TRUE)

Arguments

x

Network input: matrix, igraph, network, cograph_network, or tna object.

method

Community detection algorithm to use. One of:

  • "louvain": Louvain modularity optimization (default)

  • "walktrap": Walktrap algorithm based on random walks

  • "fast_greedy": Fast greedy modularity optimization

  • "label_prop": Label propagation algorithm

  • "infomap": Infomap algorithm based on information flow

  • "leiden": Leiden algorithm, run with the defaults of igraph::cluster_leiden(). Its default constant Potts model objective can place every node in its own community.

"louvain", "leiden" and "fast_greedy" require an undirected graph. A directed network is collapsed to an undirected one for these methods, with the weights of reciprocal edges averaged, and a message is issued for "louvain" and "leiden". The "louvain", "leiden", "label_prop" and "infomap" methods use random numbers, so set.seed() makes their result reproducible.

directed

Logical or NULL. If NULL (default), auto-detect from matrix symmetry. Set TRUE to force directed, FALSE to force undirected.

weights

Logical. Use edge weights for community detection. Default TRUE.

Value

A cograph_communities object, which inherits from data.frame and has one row per node with columns:

  • node: Node labels/names

  • community: Numeric community membership

The algorithm name, the igraph community object, the modularity and the input network are carried as attributes for the print, plot and modularity methods.

Examples

detect_communities(regulation_net, method = "walktrap")
#> Community structure (walktrap)
#>   Nodes: 10  | Communities: 2  | Modularity: 0.1976 
#>   Sizes: 5, 5 
#> 
#>        node community
#>     Explore         1
#>        Plan         2
#>     Monitor         2
#>       Adapt         1
#>     Reflect         1
#>     Discuss         1
#>  Synthesize         1
#>    Evaluate         2
#>      Create         2
#>       Share         2