public void heapDecKey(Vortex vortex, int dayDistance, double dayTravelDistance) {
		if (vortex.getDayDistance() < dayDistance) {
			return;
		}
		if (vortex.getDayDistance() == dayDistance && vortex.getDayTravelDistance() < dayTravelDistance) {
			return;
		}
		
		int i = 1;
		for (i=1; i<=length; i++) { //right upper limit?
			if (vortex.equals(heap[i])) {
				break;
			}
		}
		
		vortex.setDistance(dayDistance, dayTravelDistance);
		heapify(i);
	}