R/fd_chull_intersect.R

In fundiversity: Easy Computation of Functional Diversity Indices

# A wrapper around geometry::intersectn() to properly handle errors and specific
# cases
#' @importFrom geometry intersectn
fd_chull_intersect <- function(traits1, traits2) {

  traits1 <- traits1[!duplicated(traits1),, drop = FALSE]
  traits2 <- traits2[!duplicated(traits2),, drop = FALSE]

  if (ncol(traits1) == 1L && ncol(traits2) == 1L) {

    # Range of the overlap
    r3 <- c(max(traits1, traits2),
            min(traits1, traits2))

    r_overlap <- r3[2] - r3[1]

    return(
      list(
        "hull" = r3,
        "area" = r_overlap,
        "vol" = r_overlap
      )
    )
  }

  if (nrow(traits1) <= ncol(traits1) || nrow(traits2) <= ncol(traits2)) {
    return(
      list(
        "hull" = seq_len(nrow(traits1) + nrow(traits2)),
        "area" = NA_real_,
        "vol" = NA_real_
      )
    )
  }

  return(intersectn(traits1, traits2, options = "FA")[["ch"]])
}