An N-Body simulation program using all-pair algorithm Todos: 10, Rewrite the datasaving codes. 20, Rewrite the rendering code. (Maybe in C instead of Python.) 21, Change the rendering method. (Maybe something more mathematical, but not that mathematical.) 30, Support computing on multiple devices. (Since I haven't multiple GPUs in one PC, this might take some times.(sad)) 40, Support distributed computing. (Emmm.)