Base- and null-model codelenghts.

The codelength of a model is equal to L(H, ϕ) = Sϕ + L(ϕ) (Eq (12)), with the entropy Sϕ and the model complexity L(ϕ) given by the appropriate expressions in the table. The entropy of multigraph models are given in the first four lines and the entropy of the simple graph models are given in the next four. The parametric complexity of the models is the same for multi- and simple graphs and are listed in the following four lines. Finally, expressions for common parametric codelengths are given in the last four lines. For multigraph codes, the asymmetric and symmetric parts of the adjency matrix are denoted by and , respectively. For reciprocal models (RER and RCM), is the number of non-reciprocated edges and is the number of reciprocated edges. For the configuration model (CM), denotes the out-degrees and the in-degrees. For the reciprocal CM (RCM), and are the non-reciprocated out- and in-degrees, and are the reciprocal degrees. (Details can be found in S4 Text).