fanyan

这是一个三次样条插值函数实现的C代码。如果插值点需要改变，可以在程序中改定。(This is a cubic spline interpolation function of the realization of the C code. If interpolation points need to change, the procedures will change.)

FFT源代码 FFT源代码 FFT源代码(FFT source code FFT source code FFT source code)

fitness,适应度函数，计算适应度函数，(fitness, fitness function, calculate the fitness function,)

求解激波管问题等产生的偏微分方程组的各种数值算法。(Shock tube problem solving, such as partial differential equations arising from a variety of numerical algorithm.)

说明：  该文件是用C语言实现快速傅里叶变换的源代码，需要的朋友快下载(The document is used C language to achieve fast Fourier transform of the source code, need friends fast download)

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)

ista算法，用于最优化求解,迭代收敛，实用小程序(ista algorithm, for the most optimtical problem)

实现位场数据的向上延拓运算，有效的消除数据中的噪音及浅部干扰。(Realize the potential field data upward continuation operator, effectively eliminate the noise in the data and shallow interference.)

用DFT 函数计算电压u, 电流i的基波(f1=50 Hz)的有效值和相位; 用FFT函数分别计算电压u和电流i 所包含的直流,基波和谐波的有效值和初相角; 可计算基波(f1=50 Hz)和各次谐波的功率p和功率因数con?.(The effective value and phase of fundamental wave (f1 = 50 Hz) of voltage U and current I are calculated by DFT function. The effective values and initial phase angles of DC, fundamental and harmonic waves contained in voltage U and current I are calculated by FFT function, respectively. The power P and power factor con of fundamental wave (f1 = 50 Hz) and harmonics can be calculated.)

迭代的动力缩聚法计算结构的前两阶频率和阵型（4个自由度）(Iterative dynamic condensation method to calculate the structure of the first two natural frequencies and formation (4 degrees of freedom))