R/mat.lp.R

In SebastianSosa/ANTs: Animal Network Toolkit Software

# Copyright (C) 2018  Sebastian Sosa, Ivan Puga-Gonzalez, Hu Feng He, Xiaohua Xie, Cédric Sueur
#
# This file is part of Animal Network Toolkit Software (ANTs).
#
# ANT is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# ANT is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

#' @title Laplacian matrix
#' @description Create the laplacian matrix of a network.

#' @param M a square adjacency matrix.

#' @details  Laplacian matrix is the difference between the degrees matrix and the adjacency matrix.
#' @author Sebastian Sosa, Ivan Puga-Gonzalez.

#' @references REF laplacian !!!!!!!!!!!!!!!!
#' @references Sosa, S. (2018). Social Network Analysis, \emph{in}: Encyclopedia of Animal Cognition and Behavior. Springer.
#' @keywords internal


mat.lp <- function(M) {
  # Create the degrees matrix----------------------
  m0 <- M
  m0[m0 > 0] <- 0
  met.degree <- mat_cols_sums(M)
  diag(m0) <- met.degree

  # Create the Laplacian matrix----------------------
  LM <- m0 - M
  return(LM)
}