CCS

说明：  implementation of the zero -, first -, and second-order Bessel function

2维TE波的FDTD的源程序。周期边界条件，有限宽度的吸收边界条件(Two-dimensional TE wave FDTD source. Periodic boundary conditions, the limited width of the absorbing boundary conditions)

this document contains an explanation of mathematical functions

用欧几里得算法求两个自然数的最大公约数通过c语言实现(Using Euclidean Algorithms to Find the Maximum Common Number of Two Natural NumbersRealization by C Language)

说明：  给定求解区间，用最小二乘法给出函数的零点，并给出迭代次数(Given the solution interval, the zeros of the function are given by the least square method, and the number of iterations is given.)

说明：  基2基4基8以及分裂基的fft算法，代码效率很高。是难得一见的好代码。应用范围很广。(Radix-2-4-based 8 and split fft-based algorithm, a high code efficiency. Is a rare good code. Application of a very wide scope.)

Group delay calculation

无约束优化问题的阻尼牛顿法python代码(Damped Newton Python code for unconstrained optimization problems)

说明：  虽然现在网上的FFT程序很多，但是有的结果是错误的，比如说，经过一次正反变换后，不能得到原来的数列，所以，本人测试了多个程序，提供几个能用的，给大家，希望大家支持！ (Although many online FFT program, but some results are wrong, for example, through a positive and negative change, you can not get the original series, so I tested several programs to provide a few usable for everyone I hope we can support!)

C++中矩阵运算的实现 nr3.h为其他的书籍代码，测试环境为VS2008(Achieve C++ in matrix operations nr3 code for other books)