class Objectives implements Iterable<Entry<Objective, Value<?>>> {

	public double distance(Objectives other) {
		double[] va = this.array();
		double[] vb = other.array();

		double s = 0;
		for (int i = 0; i < va.length; i++) {
			s += (va[i] - vb[i]) * (va[i] - vb[i]);
		}

		return Math.sqrt(s);
	}

}