采用蒙特卡罗方法模拟固态相变的晶粒长大过程，可以设置3D网格大小，蒙特卡罗步等参数，适用于模拟金属再结晶过程。(The simulation model of process in grain growth is provided by this code in matlab. The parameters of mote carlo method can be inputted by the users according to th