R/dbase_fn_dom.R

In aammd/netwerk: Werks with Networks

##################
# Function for calculation of the number of degrees to basal species
# Returns a vector of the distance to the base for every species
# Producers have a default distance of 1
# Unconnected species have a distance of 0
# October 2011
# by Dominique Gravel
##################


dbase_fn <- function(L) {

  # if (nrow(L) != ncol(L)) stop("That is not a sqre")

  # stopifnot(nrow(L) == ncol(L))

  assertthat::assert_that(nrow(L) == ncol(L))

  NS <- nrow(L)

  # Remove cannibalism
  diag(L) <- 0

  # First, identify the basal species
  nprey <- apply(L, 2, sum, na.rm = TRUE)
  basal <- numeric(nrow(L))
  basal[nprey == 0] <- 1
  rk <- basal

  # Second, identify who feeds on the basal species
  for (k in 2:10) {
    for (i in 1:NS) {
      for (j in 1:NS) {
        if (rk[i] == k - 1 && rk[j] == 0 && L[i, j] == 1 && i != j) rk[j] <- k
      }
    }
  }
  return(rk)
}