graph_from_atlas() creates graphs from the book
‘An Atlas of Graphs’ by
Roland C. Read and Robin J. Wilson. The atlas contains all undirected
graphs with up to seven vertices, numbered from 0 up to 1252. The
graphs are listed:
in increasing order of number of nodes;
for a fixed number of nodes, in increasing order of the number of edges;
for fixed numbers of nodes and edges, in increasing order of the degree sequence, for example 111223 < 112222;
for fixed degree sequence, in increasing number of automorphisms.
See also
Other deterministic constructors:
graph_from_edgelist(),
graph_from_literal(),
make_(),
make_chordal_ring(),
make_circulant(),
make_empty_graph(),
make_full_citation_graph(),
make_full_graph(),
make_full_multipartite(),
make_graph(),
make_lattice(),
make_ring(),
make_star(),
make_tree(),
make_turan(),
make_wheel()
Examples
## Some randomly picked graphs from the atlas
graph_from_atlas(sample(0:1252, 1))
#> IGRAPH c677d6a U--- 7 6 -- Graph from the Atlas #282
#> + attr: name (g/c), n (g/n)
#> + edges from c677d6a:
#> [1] 1--5 1--4 2--3 3--6 6--7 3--7
graph_from_atlas(sample(0:1252, 1))
#> IGRAPH 8c0cdfe U--- 7 13 -- Graph from the Atlas #1073
#> + attr: name (g/c), n (g/n)
#> + edges from 8c0cdfe:
#> [1] 1--2 1--7 2--5 2--6 3--4 3--5 3--6 3--7 4--5 4--6 4--7 5--7 6--7