public void getPXiCi() {
		List<Integer> wine = new ArrayList<Integer>();
		Integer classs;
		for (int i = 0; i < trainNum; i++) {
			wine = trainData.get(i);
			classs = wine.get(0);
			if (classs == 1) {
				putXiNumUnderCi(pXiC1Map, wine);
			} else if (classs == 2) {
				putXiNumUnderCi(pXiC2Map, wine);
			} else if (classs == 3) {
				putXiNumUnderCi(pXiC3Map, wine);
			}
		}
		// 必须先调用getPriorProbability()求得c1、c2、c3，使用keySet()效率可能比较低，偷懒一下
		for (int i = 1; i <= 13; i++) {
			for (Integer xi : pXiC1Map.get(i).keySet()) {
				pXiC1Map.get(i).put(xi,
						pXiC1Map.get(i).get(xi) / classes.get(1));
			}
			for (Integer xi : pXiC2Map.get(i).keySet()) {
				pXiC2Map.get(i).put(xi,
						pXiC2Map.get(i).get(xi) / classes.get(2));
			}
			for (Integer xi : pXiC3Map.get(i).keySet()) {
				pXiC3Map.get(i).put(xi,
						pXiC3Map.get(i).get(xi) / classes.get(3));
			}
		}
	}