用于计算固体激光器中激光晶体的热焦距，要注意实际激光光斑大小。

用FT法实现相关函数快速估计的程序，简单明了，方法简易，适用与地球物理工作者-FT method used to achieve the estimated correlation function of the rapid procedure, simple and clear, simple methods, applicable to workers and Geophysics

傅里叶变换代码，对于地震资料处理具有一定的参考价值！-FT code for seismic data processing has certain reference value!