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Visualize a Matrix with Group Boundaries

Source: R/visualize.R
visualize.Rd

Visualize a matrix (e.g., a precision, covariance, or adjacency matrix) as a heatmap with optional group-based reordering and dashed boundary lines separating group blocks.

Usage

visualize(
  mat,
  membership,
  reorder_by_group = FALSE,
  colors = colorRampPalette(c("#00007F", "blue", "#007FFF", "cyan", "#7FFF7F", "yellow",
    "#FF7F00", "red", "#7F0000"))(256)
)

Arguments

mat

A p-by-p matrix.

membership

An integer vector specifying the group membership. The length of membership must be consistent with the dimension p.

reorder_by_group

A boolean (default = FALSE) specifying whether to reorder both rows and columns of mat according to membership, such that variables from the same group are contiguous.

colors

A vector of colors specifying an n-color gradient scale for the fill aesthetics.

Value

A ggplot2 heatmap showing the matrix entries. Dashed lines indicate group boundaries. The plot title also reports matrix dimension and sparsity.

Examples

## reproducibility for everything
set.seed(1234)

## user-defined sampler
my_gamma <- function(n) {
  rgamma(n, shape = 20, scale = 5)
}

## block-structured precision matrix based on SBM
sim <- gen_prec_sbm(p = 100, K = 5,
                    within.prob = 0.5, between.prob = 0.05,
                    weight.dists = list(my_gamma, "unif"),
                    weight.paras = list(NULL, c(min = 0, max = 1)),
                    min.eig = 0.1)

## visualization
visualize(sim$Omega, sim$membership)