is_dag {igraph}R Documentation

Directed acyclic graphs

Description

This function tests whether the given graph is a DAG, a directed acyclic graph.

Usage

is_dag(graph)

Arguments

graph

The input graph. It may be undirected, in which case FALSE is reported.

Details

is_dag() checks whether there is a directed cycle in the graph. If not, the graph is a DAG.

Value

A logical vector of length one.

Author(s)

Tamas Nepusz ntamas@gmail.com for the C code, Gabor Csardi csardi.gabor@gmail.com for the R interface.

See Also

Graph cycles feedback_arc_set(), girth(), has_eulerian_path(), is_acyclic()

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

Examples


g <- make_tree(10)
is_dag(g)
g2 <- g + edge(5, 1)
is_dag(g2)

[Package igraph version 2.0.3 Index]