R/03-updateArray.R

In Pandora-IsoMemo/resources: Food Reconstruction Using Isotopic Transferred Signals

updateArray <- function(a, x, y, z) {
  aNew <- array(NA,
    dim = c(length(x), length(y), length(z)),
    dimnames = list(x, y, z)
  )

  if (is.null(a)) {
    return(aNew)
  }

  stopifnot(length(dim(a)) == 3)

  dims <- pmin(dim(a), dim(aNew))

  for (i in seq_len(dims[1])) {
    for (j in seq_len(dims[2])) {
      for (k in seq_len(dims[3])) {
        aNew[i, j, k] <- a[i, j, k]
      }
    }
  }

  aNew
}

updateCovarianceArray <- function(a, x, y) {
  aNew <- array(diag(length(x)),
    dim = c(length(x), length(x), length(y)),
    dimnames = list(x, x, y)
  )

  if (is.null(a)) {
    return(aNew)
  }

  dims <- pmin(dim(a), dim(aNew))

  for (i in seq_len(dims[1])) {
    for (j in seq_len(dims[2])) {
      for (k in seq_len(dims[3])) {
        aNew[i, j, k] <- a[i, j, k]
      }
    }
  }

  aNew
}