本代码是matlab程序，用于模拟带电粒子在电磁场中的相对论运动。利用Boris的差分格式求解相对论牛顿-洛伦兹方程。-This code treats with the problem that the motion of charged particle in electromagnitic field. The simulation method is solving the Relativity Newton-Lorentz equation.　Boris has developed a computing method for this equation and we accept it in this code.