Is the graph a directed acyclic graph?

Provides a logical value on whether the graph is a directed acyclic graph (DAG). The conditions for a graph that is a DAG are that it should be a directed graph and it should not contain any cycles.

Usage

is_graph_dag(graph)

Arguments

graph

A graph object of class dgr_graph.

Value

A logical value.

Examples

# Create a directed graph containing
# only a balanced tree
graph_tree <-
  create_graph() %>%
  add_balanced_tree(
    k = 2, h = 3)

# Determine whether this graph
# is a DAG
graph_tree %>%
  is_graph_dag()
#> [1] TRUE

# Create a directed graph containing
# a single cycle
graph_cycle <-
  create_graph() %>%
  add_cycle(n = 5)

# Determine whether this graph
# is a DAG
graph_cycle %>%
  is_graph_dag()
#> [1] FALSE

# Create an undirected graph
# containing a balanced tree
graph_tree_undirected <-
  create_graph(
    directed = FALSE) %>%
  add_balanced_tree(
    k = 2, h = 2)

# Determine whether this graph
# is a DAG
graph_tree_undirected %>%
  is_graph_dag()
#> [1] FALSE