docs: protected void updateDensities(WritableDoubleDataStore rbod_score, DoubleDBIDList referenceDists) {
      DoubleDBIDListIter it = referenceDists.iter();
      for(int l = 0; l < referenceDists.size(); l++) {
        double density = computeDensity(referenceDists, it, l);
        // computeDensity modified the iterator, reset:
        it.seek(l);
        // NaN indicates the first run.
        if(!(density > rbod_score.doubleValue(it))) {
          rbod_score.putDouble(it, density);
        }
      }
    }