Some use-cases: * n(i,j) arbitrary. Probably have to pass an adjacency matrix (or close) of values. * n(i,j) with block structure. Requires a Run-Length-Encoded Valued Dyad Matrix that stores runs of nonzero values? * n(i,j) := min(a[i],a[j]), which arises in collapsed bipartite networks. Probably implementable as a special case.