In- or out- component of a vertex

Finds all vertices reachable from a given vertex, or the opposite: all vertices from which a given vertex is reachable via a directed path.

Usage

subcomponent(graph, v, ..., mode = c("all", "out", "in"))

Arguments

graph

The graph to analyze.

v

The vertex to start the search from.

...

These dots are for future extensions and must be empty.

mode

Character string, either “in”, “out” or “all”. If “in” all vertices from which v is reachable are listed. If “out” all vertices reachable from v are returned. If “all” returns the union of these. It is ignored for undirected graphs.

Value

Numeric vector, the IDs of the vertices in the same component as v.

Details

A breadth-first search is conducted starting from vertex v.

Related documentation in the C library

vcount()

See also

components()

Other structural.properties: bfs(), component_distribution(), connect(), constraint(), coreness(), degree(), dfs(), distance_table(), edge_density(), feedback_arc_set(), feedback_vertex_set(), girth(), is_acyclic(), is_dag(), is_matching(), k_shortest_paths(), knn(), reciprocity(), subgraph(), topo_sort(), transitivity(), unfold_tree(), which_multiple(), which_mutual()

Author

Gabor Csardi csardi.gabor@gmail.com

Examples

g <- sample_gnp(100, 1 / 200)
subcomponent(g, 1, "in")
#> Warning: Calling `subcomponent()` with positional or abbreviated arguments was
#> deprecated in igraph 3.0.0.
#> ℹ Detected call: subcomponent(graph, v, mode)
#> ℹ Use instead: subcomponent(graph, v, mode = )
#> ── <vertex sequence> 1/100 · from 8de38b5 ──────────────────────────────────────
#> [1] 1
subcomponent(g, 1, "out")
#> ── <vertex sequence> 1/100 · from 8de38b5 ──────────────────────────────────────
#> [1] 1
subcomponent(g, 1, "all")
#> ── <vertex sequence> 1/100 · from 8de38b5 ──────────────────────────────────────
#> [1] 1