cohesion_strong: Cohesion Matrix: Strong Ties

In moorekatherine/pald: Partitioned Local Depths for Community Structure in Data

Cohesion Matrix: Strong Ties

Description

Provides the symmetrized and thresholded matrix of cohesion values.

Usage

cohesion_strong(c, symmetric = TRUE)

Arguments

c	A cohesion_matrix object, a matrix of cohesion values (see cohesion_matrix).
symmetric	Logical. Whether the returned matrix should be made symmetric (using the minimum); the default is TRUE.

Details

The threshold is that provided by strong_threshold (and is equal to half of the average of the diagonal of c). Values of the cohesion matrix which are less than the threshold are set to zero. The symmetrization, if desired, is computed using the entry-wise (parallel) minimum of C and ts transpose (i.e., min(C_ij, C_ji)). The matrix provided by cohesion_strong (with default symmetric = TRUE) is the adjacency matrix for the graph of strong ties (the cluster graph), see community_graphs and pald.

Value

The symmetrized cohesion matrix in which all entries corresponding to weak ties are set to zero.

Examples

C <- cohesion_matrix(dist(exdata2))
strong_threshold(C)
cohesion_strong(C)

## To illustrate the calculation performed
C_strong <- C

## C_strong is equal to cohesion_strong(C, symmetric = FALSE)
C_strong[C < strong_threshold(C)] <- 0

## C_strong_sym is equal to cohesion_strong(C)
C_strong_sym <- pmin(C_strong, t(C_strong))

## The (cluster) graph whose adjacency matrix, CS,
## is the matrix of strong ties
CS <- cohesion_strong(C)

if (requireNamespace("igraph", quietly = TRUE)) {
G_strong <- igraph::simplify(
  igraph::graph.adjacency(CS, weighted = TRUE, mode = "undirected")
  )
plot(G_strong)
}

moorekatherine/pald documentation built on June 21, 2022, 12:21 p.m.