unfold_tree {igraph} | R Documentation |
Perform a breadth-first search on a graph and convert it into a tree or forest by replicating vertices that were found more than once.
unfold_tree(graph, mode = c("all", "out", "in", "total"), roots)
graph |
The input graph, it can be either directed or undirected. |
mode |
Character string, defined the types of the paths used for the breadth-first search. “out” follows the outgoing, “in” the incoming edges, “all” and “total” both of them. This argument is ignored for undirected graphs. |
roots |
A vector giving the vertices from which the breadth-first search is performed. Typically it contains one vertex per component. |
A forest is a graph, whose components are trees.
The roots
vector can be calculated by simply doing a topological sort
in all components of the graph, see the examples below.
A list with two components:
tree |
The result, an |
vertex_index |
A numeric vector, it gives a mapping from the vertices of the new graph to the vertices of the old graph. |
Gabor Csardi csardi.gabor@gmail.com
Other structural.properties:
bfs()
,
component_distribution()
,
connect()
,
constraint()
,
coreness()
,
degree()
,
dfs()
,
distance_table()
,
edge_density()
,
feedback_arc_set()
,
girth()
,
is_dag()
,
is_matching()
,
knn()
,
laplacian_matrix()
,
reciprocity()
,
subcomponent()
,
subgraph()
,
topo_sort()
,
transitivity()
,
which_multiple()
,
which_mutual()
g <- make_tree(10) %du% make_tree(10)
V(g)$id <- seq_len(vcount(g)) - 1
roots <- sapply(decompose(g), function(x) {
V(x)$id[topo_sort(x)[1] + 1]
})
tree <- unfold_tree(g, roots = roots)