hurst_exponent

国外最近的一篇变步长nlms仿真，该文件有文中的几种仿真(Recent foreign nlms a variable step simulation, there is the text of the document of several simulation)

Umat for GTN damage material model in Abaqus by UMAT - STATIC in Levenberg-Marquardt (LM) solution routines from Slatec library

fsolve函数求非线性方程组数值解，已经验证其正确性。(fsolve function for the numerical solution of nonlinear equations)

关于非线性离散系统辨识，小波包分析提取振动信号中的特征频率，有小波分析的盲信号处理。( Nonlinear discrete system identification, Wavelet packet analysis to extract vibration signal characteristic frequency, There Wavelet Analysis Blind Signal Processing.)

说明：  隐马尔可夫的经典文献，和通俗易懂的PPT，很好的经典资料，文献常被应用，甚至PPT都经常被模仿(Hidden Markov classic literature, and user-friendly PPT, classic good information, the literature is often applied, or even PPT are often imitate)

1. 牛顿迭代法 function [x,i]=newtonmethod(x0,f,ep,Nmax) 牛顿法求非线性方程根 x0是输入初始值, f是输入函数, 精度要求ep, Nmax为最大迭代次数 x是输出迭代序列,i是迭代次数 2. 二分法 function [x,k]=bisection(a,b,f,ep) 二分法解非线性方程 输入区间[a,b],函数f和误差ep, Nmax为最大二分次数 x为输出近似根, k为二分次数 ( Newton s law and the dichotomy)

共轭梯度法（Conjugate Gradient）是介于最速下降法与牛顿法之间的一个方法，它仅需利用一阶导数信息，但克服了最速下降法收敛慢的缺点，又避免了牛顿法需要存储和计算Hesse矩阵并求逆的缺点，共轭梯度法不仅是解决大型线性方程组最有用的方法之一，也是解大型非线性最优化最有效的算法之一(Conjugate gradient method (Conjugate Gradient) is between the steepest descent method and Newton' s method between a method that takes only a first derivative information, but to overcome the slow convergence of the steepest descent method shortcomings, but also avoid the need to store Newton and computing the inverse Hesse matrix and disadvantages, conjugate gradient method is not only to solve large linear equations of the most useful methods, large-scale nonlinear optimization solution is the most efficient algorithms)

cpsd 单独子函数，可编译后直接应用于自己的程序，方便快捷，使用fftw库(cpsd separate sub-functions can be applied directly after compiling its own procedures, convenient use fftw library)

甲烷的19步简化反应机理文件，FORTRAN语言编写反应速度(ch4 reaction rate)

3DFFT,对三维数据进行傅立叶变换，效果较好.可以用于三维的地震资料处理(3DFFT, three-dimensional Fourier transform of the data, the better can be used for three-dimensional seismic data processing)