1. Key Laboratory of Pattern Recognition and Intelligent Information Processing, Institutions of Higher Education of Sichuan Province, Chengdu University, Chengdu, China;
2. Department of Computer Science and Engineering, Air University Multan Campus, Multan, Pakistan;
3. Department of Mathematics, Comsats University Islamabad, Islamabad, Pakistan;
4. College of chemistry, School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, China