计算体系的形成能.输入参数：不同电荷背景下体系的能量。杂质院子的化学势-calculating the formation energy

有限元的MATLAB程序，该MATLAB程序使用有限元法解决连续体的位移及受力问题。使用限制：节点处可受集中力，每一单元可受一个集中力，每边可受一常值边界力-Finite element MATLAB program, the problem of the MATLAB program using the finite element method to solve the continuum displacement and stress. Use restrictions: nodes un