# Function to permute arrays of non-atomic elements (e.g. POSIXct)
.aperm2 <- function(x, new_order) {
  y <- array(1:length(x), dim = dim(x))
  y <- aperm(y, new_order)
  old_dims <- dim(x)
  x <- x[as.vector(y)]
  dim(x) <- old_dims[new_order]
  x
}