A graph is considered complete if there is an edge between all distinct directed pairs of vertices. igraph considers both the singleton graph and the null graph complete.
is_complete(graph)True if the graph is complete.
Other cliques:
cliques(),
ivs(),
weighted_cliques()
g <- make_full_graph(6, directed = TRUE)
is_complete(g)
#> [1] TRUE
g <- delete_edges(g, 1)
is_complete(g)
#> [1] FALSE
g <- as_undirected(g)
is_complete(g)
#> [1] TRUE