Warning

This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.

networkx.generators.degree_seq.havel_hakimi_graph

havel_hakimi_graph(deg_sequence, create_using=None)

Return a simple graph with given degree sequence constructed using the Havel-Hakimi algorithm.

Parameters:

• deg_sequence (list of integers) – Each integer corresponds to the degree of a node (need not be sorted).
• create_using (NetworkX graph constructor, optional (default=nx.Graph)) – Graph type to create. If graph instance, then cleared before populated. Directed graphs are not allowed.

Raises:

NetworkXException – For a non-graphical degree sequence (i.e. one not realizable by some simple graph).

Notes

The Havel-Hakimi algorithm constructs a simple graph by successively connecting the node of highest degree to other nodes of highest degree, resorting remaining nodes by degree, and repeating the process. The resulting graph has a high degree-associativity. Nodes are labeled 1,.., len(deg_sequence), corresponding to their position in deg_sequence.

The basic algorithm is from Hakimi [1] and was generalized by Kleitman and Wang [2].

References

[1]	Hakimi S., On Realizability of a Set of Integers as Degrees of the Vertices of a Linear Graph. I, Journal of SIAM, 10(3), pp. 496-506 (1962)

[2]	Kleitman D.J. and Wang D.L. Algorithms for Constructing Graphs and Digraphs with Given Valences and Factors Discrete Mathematics, 6(1), pp. 79-88 (1973)