public static void initItemFeature() {  

		double sum;
		
		for(int i = 0; i < DataInfo.num_of_item;i++) {		
			sum = 0;
			for(int j = 0; j < DataInfo.itemlist[i].length; j++) {
				int a = DataInfo.itemlist[i][j];
				sum += a % 10;
			}
			DataInfo.itemFeature[i][0] = sum / DataInfo.num_of_user;
		}
		
		Random rand = new Random();
		for (int i = 0; i != DataInfo.num_of_item; ++i) {
			for (int j = 1; j != DataInfo.featureNumber; ++j) {
				DataInfo.itemFeature[i][j] = rand.nextDouble();    //其他的空用随机数填
			}
		}
	}