optimize comments
optimize comments

apache/incubator-singa,nudles/incubator-singa,apache/incubator-singa,nudles/incubator-singa,nudles/incubator-singa,apache/incubator-singa,apache/incubator-singa,apache/incubator-singa,nudles/incubator-singa,nudles/incubator-singa