1. School of Mathematics and Statistics, Northwestern Polytechnical University, Xi'an 710129, China
2. NPU-UoG International Cooperative Lab for Computation and Application in Cardiology, Xi'an 710129, China
3. Xi'an Key Laboratory of Scientific Computation and Applied Statistics, Xi'an 710129, China
4. School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
5. School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ, UK