Search code examples
rgraphigraphedgessubgraph

constructing complete subgraph in igraph


I'm pretty new to R. I wanna know that given a list of node ID's of a graph is there any fast way to connect all the edges between that vertices and create a clique in that graph?

p.s: I'm looking for a really fast method because I'm working on a very large graph.

Thanks in advance.


Solution

  • Given a vector of vertices idx, we may use combn to create a vector of edges to be added:

    g1 <- erdos.renyi.game(20, 1 / 20)
    idx <- 3:8
    g2 <- g1 + edges(c(combn(idx, 2)))
    maximal.cliques(g2)
    # ...
    # [[14]]
    # + 6/20 vertices, from 137d7ad:
    # [1] 6 3 8 7 5 4