igraph (version 1.0.0)

cluster_label_prop: Finding communities based on propagating labels

Description

This is a fast, nearly linear time algorithm for detecting community structure in networks. In works by labeling the vertices with unique labels and then updating the labels by majority voting in the neighborhood of the vertex.

Usage

cluster_label_prop(graph, weights = NULL, initial = NULL, fixed = NULL)

Arguments

graph

The input graph, should be undirected to make sense.

weights

An optional weight vector. It should contain a positive weight for all the edges. The weight edge attribute is used if present. Supply NA here if you want to ignore the weight edge attribute.

initial

The initial state. If NULL, every vertex will have a different label at the beginning. Otherwise it must be a vector with an entry for each vertex. Non-negative values denote different labels, negative entries denote vertices without labels.

fixed

Logical vector denoting which labels are fixed. Of course this makes sense only if you provided an initial state, otherwise this element will be ignored. Also note that vertices without labels cannot be fixed.

Value

• cluster_label_prop returns a communities object, please see the communities manual page for details.

Details

This function implements the community detection method described in: Raghavan, U.N. and Albert, R. and Kumara, S.: Near linear time algorithm to detect community structures in large-scale networks. Phys Rev E 76, 036106. (2007). This version extends the original method by the ability to take edge weights into consideration and also by allowing some labels to be fixed.

From the abstract of the paper: In our algorithm every node is initialized with a unique label and at every step each node adopts the label that most of its neighbors currently have. In this iterative process densely connected groups of nodes form a consensus on a unique label to form communities.

References

Raghavan, U.N. and Albert, R. and Kumara, S.: Near linear time algorithm to detect community structures in large-scale networks. Phys Rev E 76, 036106. (2007)

See Also

communities for extracting the actual results.

cluster_fast_greedy, cluster_walktrap and cluster_spinglass for other community detection methods.

Examples

g <- sample_gnp(10, 5/10) %du% sample_gnp(9, 5/9)
  g <- add_edges(g, c(1, 12))
  cluster_label_prop(g)