public Double getAccBinary(long timestamp, List<AccMagn> magns) {
		long minTimestamp = magns.get(0).getTimestamp();
		long maxTimestamp = magns.get(magns.size() - 1).getTimestamp();
		int low = 0;
		int high = magns.size() - 1;

		if ((magns.size() == 0) || (timestamp < minTimestamp || timestamp > maxTimestamp)) {
			return null;
		}

		while (low < high) {
			int mid = (low + high) / 2;
			assert (mid < high);
			long d1 = Math.abs(magns.get(mid).getTimestamp() - timestamp);
			long d2 = Math.abs(magns.get(mid + 1).getTimestamp() - timestamp);
			if (d2 <= d1) {
				low = mid + 1;
			} else {
				high = mid;
			}
		}
		return magns.get(high).getVectorLength();
	}