R/nimp.R

In stefvanbuuren/dsMice: DataSHIELD server-side functions for the mice package

#' Number of imputations per block
#'
#' Calculates the number of cells within a block for which imputation 
#' is requested.
#' @inheritParams mice
#' @return  A numeric vector of length \code{length(blocks)} containing 
#' the number of cells that need to be imputed within a block.
#' @seealso \code{\link{mice}}
#' @export
#' @examples 
#' where <- is.na(nhanes)
#' 
#' # standard FCS
#' nimp(where)
#' 
#' # user-defined blocks
#' 
nimp <- function(vars=NULL) {
  
  where <- identifyNas(vars)$nas
  blocks <- make.blocksDS(where)
  nwhere <- apply(where, 2, sum)
  nimp <- vector("integer", length = length(blocks))
  names(nimp) <- names(blocks)
  
  for (i in seq_along(blocks)) {
    nimp[i] <- sum(nwhere[blocks[[i]]])
  }
  
  return(nimp)
}