code: protected Cluster<SubspaceModel> makeCluster(Relation<V> relation, DBIDs C, long[] D) {
      DBIDs ids = DBIDUtil.newHashSet(C); // copy, also to lose distance values!
      Cluster<SubspaceModel> cluster = new Cluster<>(ids);
      cluster.setModel(new SubspaceModel(new Subspace(D), Centroid.make(relation, ids).getArrayRef()));
      return cluster;
    }
docs: Utility method to create a subspace cluster from a list of DBIDs and the
  relevant attributes.
  
  @param relation to compute a centroid.
  @param C the cluster points.
  @param D the relevant dimensions.
  @return an object representing the subspace cluster.