1. College of Science, Minzu University of China, Beijing, People's Republic of China
2. Institute of Computational Mathematics and Scientific/Engineering Computing, State Key Laboratory of Scientific and Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, People's Republic of China
3. Program in Applied Mathematical and Computational Sciences (AMCS), Department of Mathematics, University of Iowa, Iowa City, IA, USA
4. School of Mathematics and Statistics, Central South University, Changsha, People's Republic of China