R/getnnsvar.R

In ClustOfVar: Clustering of Variables

#' @export
#' @name getnnsvar
#' @title Nearest neighbor of variables
#' @description Nearest neighbor of variables
#' @param diss a dissimilarity matrix between variables
#' @param flag a vector of size \code{p} which indicates if we want to compute nearest
#'  neighbor of variable j (flag[j]=1) or not (flag[j]=0)


getnnsvar <- function(diss, flag) {
  # Inputs.  diss: full distance matrix.
  #          flag: "live" rows indicated by 1 are to be processed.
  # Returns. List of: nn, nndiss.
  #          nn:   list of nearest neighbor of each row.
  #          nndiss: nearest neigbbor distance of each row.
  
  mini.vec.flag<-function(vect_flag){
    L<-length(vect_flag)
    flagi<-vect_flag[L]
    vect<-vect_flag[-L]
    if (flagi==0){res<-c(0,0)}
    else{
      search.min<-which(vect==min(vect[vect>0]))[1]
      minobs<-search.min
      mindis<-vect[search.min]
      res<-c(round(minobs,1),mindis)
    }
    return(res)                          
  }
  
  res<-apply(cbind(diss,flag),1,FUN=mini.vec.flag)
  result<-list(nn=res[1,],nndiss=res[2,])
  return(result)
}