docs: static double initialWeights(WritableDoubleDataStore weights, DBIDs ids, NumberVector first, DistanceQuery<? super NumberVector> distQ) {
      double weightsum = 0.;
      for(DBIDIter it = ids.iter(); it.valid(); it.advance()) {
        // Distance will usually already be squared
        double weight = distQ.distance(first, it);
        weights.putDouble(it, weight);
        weightsum += weight;
      }
      return weightsum;
    }