Markov Clustering (MCL) for community detection

Source: R/gs_cluster.R

This function implements the Markov Clustering (MCL) algorithm for finding community structure, in an analogous way to other existing algorithms in igraph.

cluster_markov(
  g,
  add_self_loops = TRUE,
  loop_value = 1,
  mcl_expansion = 2,
  mcl_inflation = 2,
  allow_singletons = TRUE,
  max_iter = 100,
  return_node_names = TRUE,
  return_esm = FALSE
)

Arguments

g

The input graph object

add_self_loops

Logical, whether to add self-loops to the matrix by setting the diagonal to loop_value

loop_value

Numeric, the value to use for self-loops

mcl_expansion

Numeric, cluster expansion factor for the Markov clustering iteration - defaults to 2

mcl_inflation

Numeric, cluster inflation factor for the Markov clustering iteration - defaults to 2

allow_singletons

Logical; if TRUE, single isolated vertices are allowed to form their own cluster. If set to FALSE, all clusters of size = 1 are grouped in one cluster (to be interpreted as background noise).

max_iter

Numeric value for the maximum number of iterations for the Markov clustering

return_node_names

Logical, if the graph is named and set to TRUE, returns the node names.

return_esm

Logical, controlling whether the equilibrium state matrix should be returned

Value

This function returns a communities object, containing the numbers of the assigned membership (in the slot membership). Please see the igraph::communities() manual page for additional details

Details

This implementation has been driven by the nice explanations provided in

  • https://sites.cs.ucsb.edu/~xyan/classes/CS595D-2009winter/MCL_Presentation2.pdf

  • https://medium.com/analytics-vidhya/demystifying-markov-clustering-aeb6cdabbfc7

  • https://github.com/GuyAllard/markov_clustering (python implementation)

More info on the MCL: https://micans.org/mcl/index.html, and https://micans.org/mcl/sec_description1.html

References

van Dongen, S.M., Graph clustering by flow simulation (2000) PhD thesis, Utrecht University Repository - https://dspace.library.uu.nl/handle/1874/848

Enright AJ, van Dongen SM, Ouzounis CA, An efficient algorithm for large-scale detection of protein families (2002) Nucleic Acids Research, Volume 30, Issue 7, 1 April 2002, Pages 1575–1584, https://doi.org/10.1093/nar/30.7.1575

Examples

library("igraph")
#> 
#> Attaching package: ‘igraph’
#> The following object is masked from ‘package:GenomicRanges’:
#> 
#>     union
#> The following object is masked from ‘package:IRanges’:
#> 
#>     union
#> The following object is masked from ‘package:S4Vectors’:
#> 
#>     union
#> The following objects are masked from ‘package:BiocGenerics’:
#> 
#>     normalize, path, union
#> The following objects are masked from ‘package:stats’:
#> 
#>     decompose, spectrum
#> The following object is masked from ‘package:base’:
#> 
#>     union
g <- make_full_graph(5) %du% make_full_graph(5) %du% make_full_graph(5)
g <- add_edges(g, c(1, 6, 1, 11, 6, 11))
cluster_markov(g)
#> IGRAPH clustering mcl, groups: 3, mod: NA
#> + groups:
#>   $`1`
#>   [1] 1 2 3 4 5
#>   
#>   $`2`
#>   [1]  6  7  8  9 10
#>   
#>   $`3`
#>   [1] 11 12 13 14 15
#>   
V(g)$color <- cluster_markov(g)$membership
plot(g)