overlapF(x, y)

Functional overlap between two TPD distributions (Bhattacharyya coefficient).

functional diversity

Args:x — first TPD objecty — second TPD object

overlapF <- function(x, y) {
  if (!identical(x$eval.points, y$eval.points)) stop("Not identical eval points!")
  TPDx <- x$estimate
  if (class(x$eval.points) == "list") {
    x$eval.points <- expand.grid(x$eval.points)
  }
  cellEdge <- numeric()
  for (i in 1:ncol(x$eval.points)) {
    cellEdge[i] <- unique(x$eval.points[, i])[2] - unique(x$eval.points[, i])[1]
  }
  cellSizex <- prod(cellEdge)
  TPDx <- TPDx * cellSizex
  TPDx <- TPDx / sum(TPDx)

  TPDy <- y$estimate
  TPDy <- TPDy * cellSizex
  TPDy <- TPDy / sum(TPDy)

  OL <- sum(pmin(TPDx, TPDy))
  return(OL)
}