radial centrality layout

arranges nodes in concentric circles according to a centrality index.

Usage

layout_with_centrality(
  g,
  cent,
  scale = TRUE,
  iter = 500,
  tol = 1e-04,
  tseq = seq(0, 1, 0.2)
)

layout_igraph_centrality(
  g,
  cent,
  scale = TRUE,
  iter = 500,
  tol = 1e-04,
  tseq = seq(0, 1, 0.2),
  circular
)

Arguments

g: igraph object
cent: centrality scores
scale: logical. should centrality scores be scaled to \([0,100]\)? (Default: TRUE)
iter: number of iterations during stress optimization
tol: stopping criterion for stress optimization
tseq: numeric vector. increasing sequence of coefficients to combine regular stress and constraint stress. See details.
circular: not used

Value

matrix of xy coordinates

Details

The function optimizes a convex combination of regular stress and a constrained stress function which forces nodes to be arranged on concentric circles. The vector tseq is the sequence of parameters used for the convex combination. In iteration i of the algorithm \(tseq[i]\) is used to combine regular and constraint stress as \((1-tseq[i])*stress_{regular}+tseq[i]*stress_{constraint}\). The sequence must be increasing, start at zero and end at one. The default setting should be a good choice for most graphs.

The layout_igraph_* function should not be used directly. It is only used as an argument for plotting with 'igraph'. 'ggraph' natively supports the layout.

References

Brandes, U., & Pich, C. (2011). More flexible radial layout. Journal of Graph Algorithms and Applications, 15(1), 157-173.

Examples

library(igraph)

g <- sample_gnp(10, 0.4)
if (FALSE) { # \dontrun{
library(ggraph)
ggraph(g, layout = "centrality", centrality = closeness(g)) +
    draw_circle(use = "cent") +
    geom_edge_link0() +
    geom_node_point(shape = 21, fill = "grey25", size = 5) +
    theme_graph() +
    coord_fixed()
} # }