code: private boolean isReferenceResult(Clustering<?> t) {
      // FIXME: don't hard-code strings
      return "bylabel-clustering".equals(t.getShortName()) //
          || "bymodel-clustering".equals(t.getShortName()) //
          || "allinone-clustering".equals(t.getShortName()) //
          || "allinnoise-clustering".equals(t.getShortName());
    }
docs: Test if a clustering result is a valid reference result.
  
  @param t Clustering to test.
  @return {@code true} if it is considered to be a reference result.