code: @Override
  	public double weightedJaccardSimilarity(IntSet other) {
  		if (isEmpty() && other.isEmpty())
  			return 1D;
  		IntIterator itr = intersection(other).iterator();
  		double intersectionSum = 0D;
  		while (itr.hasNext()) 
  			intersectionSum += itr.next();
  
  		itr = symmetricDifference(other).iterator();
  		double symmetricDifferenceSum = 0D;
  		while (itr.hasNext()) 
  			symmetricDifferenceSum += itr.next();
  		
  		return intersectionSum / (intersectionSum + symmetricDifferenceSum);
  	}
docs: {@inheritDoc}