R/similarity_l.R

In mbojan/linkprediction: Link Prediction Methods

# Pseudoinverse of the Laplacian
#
# Similarity measure based solely on the pseudoinverse of the Laplacian matrix
#
# The pseudo inverse of the Laplacian matrix provides provides a direct measure
#   of similarity, as its elements are the inner products of vectors from an
#   Euclidean space, which preserves Average Commute Time between nodes.
#

similarity_l <- function(graph, v1, v2, ...){
  L <- igraph::graph.laplacian(graph)
  n <- igraph::vcount(graph)

  score <- solve(L - 1/n) + 1/n
  score[v1, v2]
}