R/tcub_adapt_sorted.R

In mgwrsar: GWR and MGWR with Spatial Autocorrelation

#' tcub_adapt_sorted
#' to be documented
#' @usage tcub_adapt_sorted(d,h)
#' @param d a vector of distances
#' @param h a scalar or vector of number of neighbours as bandiwdths (lenght(h)=1 or length(h)=length(d))
#' @noRd
#' @return a vector of weights.
tcub_adapt_sorted <- function(d,h) {     #bisquare kernel
  if(is.unsorted(d[1,])) {
    dd=t(apply(d,1,sort))
  } else dd=d
  if(any(h!=h[1])) {h <- dd[cbind(1:nrow(dd),h+2)]} else h=dd[,h[1]+2]
  x<-abs(d/h)
  x[x< 1]<- (70/81)*((1-x[x< 1]^3)^3)
  x[x>= 1]<- 0
  x
}