#' @title Compute rows
#' @description Individuals inds have been given. The function returns a vector,
#' containing the indices of the rows, which contain data from the individuals.
#' @param rowsFromInd rowsFromInd
#' @param inds matrix
#' @param ninds ninds
computeRows <- function(rowsFromInd, inds, ninds) {
  if (!is(inds, "matrix")) inds <- as.matrix(inds)
  if (identical(dim(inds), c(nrow(inds), 1L))) {
    # Special treatment for vectors because R has col vectors by default,
    # whereas Matlab has row vectors by default.
    inds <- t(inds)
    if (ninds == 0) {
      return(matrix(, 1, 0))
    }
  }
  rows <- inds[, rep(1, rowsFromInd)]
  rows <- rows * rowsFromInd
  miinus <- repmat(t((rowsFromInd - 1):0), c(ninds, 1))
  rows <- rows - miinus
  rows <- matrix(t(rows), c(1, rowsFromInd * ninds))
  return(t(rows))
}