说明：  此Matlab代码实现了Drude-Lorentz和Debye-Lorentz算法(LD模型)，用于计算金属的介电常数。当然Drude-Lorentz方法也可以用来计算纯水的。
(This Matlab code implements the Drude-Lorentz and Debye-Lorentz algorithm (LD model), used to calculate the dielectric constant of metal. Of course, Drude-Lorentz method can also be used to calculate the pure water.)