Iterators in igraph

  LargeScaleCommunityFast <- function(g, mode="all") {
    cat(“Assigning initial communities…\n”)
    vgroups <- V(g)$name
    # random order in which vertices will be processed
    cat(“Generating random order…\n”)
    order <- sample(vcount(g), vcount(g))
    t <- 0
    done <- FALSE

    while (!done) {
      t <- t + 1
      cat(“round: “, t, “\n”)

      ## change to FALSE whenever a node changes groups
      done <- TRUE

      for(i in order) {
        ## get the neighbor group frequencies:
        group.freq <- table(vgroups[neighbors(g, i, mode = mode)])
        ## pick one of the most frequent:
        new.group <- sample(names(group.freq)[group.freq == max(group.freq)], 1)
        if (done) {
          ## we are only done if new group is the same as old group
          done <- (new.group == vgroups[i])
        }
        vgroups[i] <- new.group
      }
    }

    cat(“Creating community-object…\n”)
    comms <- list(membership = as.numeric(vgroups),
                  vcount = vcount(g),
                  algorithm = “LPA”,
                  names = V(g)$name)
    class(comms) <- "communities"
    return(comms)
}

Executing the algorithm