This term adds one statistic to the model, equal to the sum of the covariate values
for each edge appearing in the network, where the covariate value for a given edge is determined by its mixing type on
attr. Undirected networks are regarded as having undirected mixing, and it is assumed that mat is symmetric
in that case.
This term can be useful for simulating large networks with many mixing types, where nodemix would be slow due to
the large number of statistics, and edgecov cannot be used because an adjacency matrix would be too big.
# binary: attrcov(attr, mat)a vertex attribute specification (see Specifying Vertex attributes and Levels (?nodal_attributes) for details.)
a matrix of covariates with the same dimensions as a mixing matrix for attr
ergmTerm for index of model terms currently visible to the package.
ergm:::.formatTermKeywords("ergmTerm", "attrcov", "subsection")