Use this if you are using igraph from R
Determine whether the given vertex degrees (in- and out-degrees for directed graphs) can be realized in a simple graph, i.e. a graph without multiple or loop edges.
is_graphical(out.deg, in.deg = NULL)
Integer vector, the degree sequence for undirected graphs, or the out-degree sequence for directed graphs.
A logical scalar.
Tamas Nepusz email@example.com
Hakimi SL: On the realizability of a set of integers as degrees of the vertices of a simple graph. J SIAM Appl Math 10:496-506, 1962.
PL Erdos, I Miklos and Z Toroczkai: A simple Havel-Hakimi type algorithm to realize graphical degree sequences of directed graphs. The Electronic Journal of Combinatorics 17(1):R66, 2010.
Other graphical degree sequences:
g <- sample_gnp(100, 2/100) is_degseq(degree(g)) is_graphical(degree(g))