public static <A> Map<String,Integer> groupCount(Iterable<A> col,
			F1<A, String> groupF) {
		HashMap<String, AtomicInteger> result = new HashMap<String, AtomicInteger>();
		for (A a : col) {
			String group = groupF.e(a);
			
			MathUtil.increase(group, result);
		}
		return MathUtil.intMap(result);
	}