divisors n builds the graph of divisors. Vertices are integers from 2 to n. i is connected to j if and only if i divides j.

• raises Invalid_argument

  is n < 2.

de_bruijn n builds the de Bruijn graph of order n. Vertices are bit sequences of length n (encoded as their interpretation as binary integers). The sequence xw is connected to the sequence wy for any bits x and y and any bit sequence w of length n-1.

• raises Invalid_argument

  is n < 1 or n > Sys.word_size-1.

vertex_only n builds a graph with n vertices and no edge.

full n builds a graph with n vertices and all possible edges. The optional argument self indicates if loop edges should be added (default value is true).