void kmeans_clustering_method::batch_update(wplist points) {
  if (points.empty()) {
    kcenters_.clear();
    return;
  }
  initialize_centers(points);
  do_batch_update(points);
}
void kmeans_clustering_method::batch_update(wplist points) {
  initialize_centers(points);
  do_batch_update(points);
}