[1] Beihang Univ, Sch Math Sci, Beijing 102206, Peoples R China
[2] Chongqing Univ technol, Chongqing 400054, Peoples R China
[3] Univ Wuppertal, Chair Appl & Computat Math, Sch Math & Nat Sci, D-42119 Wuppertal, Germany
[4] Sichuan Normal Univ, Ctr Computat Sci, Sch Phys & Elect Engn, Chengdu 610066, Peoples R China