T2F

代码说明：

  T2F子函数，在做傅里叶变换时调用。我一开始编程序时忘了加它，结果WARN ME 说未定义T2F。(T2F subroutine, called when doing Fourier transform. I started to compile the program forgot to add it, and the result is undefined WARN ME said T2F.)