private function computeDistances($object, $followers, $distanceComputeCallback)
	{
		$distances = array();
		foreach($followers as $follower)
		{
			if($follower == $object)
				continue;
			$distances[$follower->id] = call_user_func($distanceComputeCallback, $object->data, $follower->data);
		}
		return $distances;
	}