igraph in R - find all accessible vertices

4
votes

is there a way to find all accessible vertices of an igraph in R, like the function acc in the graph package? I can only find a function for adjacent vertices in an igraph but not accessible vertices.

To give some context, I have a hierarchical graph, and I want to find all nodes below. I can do this with the acc function for a graph object. However, acc doesn't work with igraph

nodesBelow <- function(graph, nodes) {
        sub <- character()
        for(node in nodes){
        sub <- c(sub, c(names(acc(graph, node)[[1]]),node))
    }
    sub <- unique(sub)
subGraph(sub, graph)
}
1
rgraphigraph

1 Answers

6
votes

There is subcomponent- example:

g1 <- graph.tree(n = 8, children = 2, mode = "out" )
print.igraph(g1,full = TRUE)

# IGRAPH D--- 8 7 -- Tree
# + attr: name (g/c), children (g/n), mode (g/c)
# + edges:
#   [1] 1->2 1->3 2->4 2->5 3->6 3->7 4->8

subcomponent(g1, 2, mode = "out")
#[1] 2 4 5 8