mutualL-ergmTerm: Mutuality

Description

In binary ERGMs, equal to the number of pairs of actors \(i\) and \(j\) for which \((i{\rightarrow}j)\) and \((j{\rightarrow}i)\) both exist.

# binary: mutualL(same=NULL, diff=FALSE, by=NULL, keep=NULL, Ls=NULL)

same: optional argument. If passed the name of a vertex attribute, only mutual pairs that match on the attribute are counted. Only one of same or by may be used. If both parameters are passed, same takes precedent. This parameter is affected by diff.
diff: separate counts for each unique matching value can be obtained by using diff=TRUE with same.
by: each node is counted separately for each mutual pair in which it occurs and the counts are tabulated by unique values of the attribute if passed the name of a vertex attribute. This means that the sum of the mutual statistics when by is used will equal twice the standard mutual statistic. Only one of same or by may be used. If both parameters are passed, same takes precedent. This parameter is not affected by diff.
keep: a numerical vector to specify which statistics should be kept whenever the mutual term would ordinarily result in multiple statistics.
Ls: a list (constructed by list() or c() of one or two Layer Logic specifications (c.f. Layer Logic section in the Layer() documentation). If given, the statistic will count the number of dyads where a tie in Ls[[1]] reciprocates a tie in Ls[[2]] and vice versa. (Note that dyad that has mutual ties in Ls[[1]] and in Ls[[2]] will add 2 to this statistic.) If a formula is given, it is replicated.

This term can only be used with directed networks.