public void getSample(int numUsers, int numItems) throws Exception {
		int rows = rateMatrix.numRows();
		int cols = rateMatrix.numColumns();
		int users = numUsers <= 0 || numUsers > rows ? rows : numUsers;
		int items = numItems <= 0 || numItems > cols ? cols : numItems;

		int[] userIds = Randoms.nextNoRepeatIntArray(users, rows);
		int[] itemIds = Randoms.nextNoRepeatIntArray(items, cols);

		String path = FileIO.desktop + "sample.txt";
		FileIO.deleteFile(path);

		List<String> lines = new ArrayList<>(2000);
		int cnt = 0;
		for (int userId : userIds) {
			for (int itemId : itemIds) {
				double rate = rateMatrix.get(userId, itemId);
				if (rate > 0) {
					lines.add((userId + 1) + " " + (itemId + 1) + " " + (float) rate);
					cnt++;
					if (lines.size() >= 1500) {
						FileIO.writeList(path, lines, null, true);
						lines.clear();
					}
				}
			}
		}
		if (lines.size() > 0)
			FileIO.writeList(path, lines, null, true);

		Logs.debug("Sample [size: {}] has been created!", cnt);
	}