R/internal.R

In vmsbase: GUI Tools to Process, Analyze and Plot Fisheries Data

## Cluster - Internal Utilities
## ============================ (new by Martin M?chler)

## This was size(); seems slightly useful in general
sizeDiss <- function(d) {
  ## find 'n' for d == dissimilarity-like(<n obs.>), i.e. length(d)= n(n-1)/2
  discr <- 1 + 8 * length(d)
  sqrtdiscr <- round(sqrt(discr))
  if (sqrtdiscr^2 == discr) (1 + sqrtdiscr) / 2 else NA
}

## used in  ./agnes.q, ./clara.q,  ./diana.q  und ./pam.q :

lower.to.upper.tri.inds <- function(n) {
  n1 <- as.integer(n - 1)
  if (n1 < 1) {
    stop("'n' must be >= 2")
  } else if (n1 == 1) {
    1L
  } else {
    rep(1:n1, 1:n1) +
      c(0, unlist(lapply(2:n1, function(k) cumsum(c(0, (n - 2):(n - k))))))
  }
}

upper.to.lower.tri.inds <- function(n) {
  if ((n2 <- as.integer(n - 2)) < 0) stop("'n' must be >= 2")
  rep(1 + cumsum(0:n2), (n - 1):1) +
    unlist(lapply(0:n2, function(k) cumsum(k:n2)))
}

## consider to *not* export these when I will use a name space :

meanabsdev <- function(y) mean(abs(y - mean(y, na.rm = TRUE)), na.rm = TRUE)