Acyclic graphs and feedback sets

A directed acyclic graph (DAG) is a directed graph with no directed cycles. For directed graphs, only directed cycles are considered.

Usage

is_dag(graph)

is_acyclic(graph)

topological_sorting(graph, mode = 1L)

Source

https://igraph.org/c/doc/igraph-Cycles.html#acyclic-graphs-feedback-sets

Arguments

graph

An igraph_ptr object.

mode

An integer value of edge type to count; {1: OUT, 2: IN, 3: ALL}.

Value

A logical value.

See also

permutate_vertices() to use the output of topological_sorting().

Examples

dag = graph_tree(5L)
tree = graph_tree(5L, mode = 2L)
ring = graph_ring(5L)

is_dag(dag)
#> [1] TRUE
is_dag(tree)
#> [1] FALSE
is_dag(ring)
#> [1] FALSE

is_acyclic(dag)
#> [1] TRUE
is_acyclic(tree)
#> [1] TRUE
is_acyclic(ring)
#> [1] FALSE

topological_sorting(dag)
#> [1] 1 2 3 4 5