R/dbase_fn_dom.R

In vcameron1/netwerk: Calculate network things

##################
# 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) {

  # Checks
  assertthat::assert_that(nrow(L) == ncol(L)) # package to throw error message
  #stopifnot(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]%in%1 && i!=j) rk[j] = k 
			}
		  }		
		}
	return(rk)
}