R/collapseAndReorderEdgelist.R

In apear9/SSNdesign: An R Package for Optimal and Adaptive Sampling Designs on Stream Networks

collapseAndReorderEdgelist <- function(edgelist){
  squashed_edgelist <- matrix(edgelist, ncol = 1)
  nrows <- nrow(edgelist)
  ordering <- c(2 * 1:nrows - 1, 2 * 1:nrows)
  squashed_edgelist <- cbind(squashed_edgelist, ordering)
  squashed_edgelist <- squashed_edgelist[order(squashed_edgelist[,"ordering"]), -2]
  return(squashed_edgelist)
}