chenggongjiao

说明：  最小二乘法拟合曲线的一个小程序，采用C++程序，(Least-squares fitting curve C++ program)

C-means in 2 types. C=2

可以求解雷洛方程的膜厚和载荷方程，读者可以稍微修改相关参数就可以应用到自己的公式和相关数学模型中(Reynolds model to develop the film-thickness and hydrodynamic load. )

计算fft，输出频谱，相位，模值,Calculation of FFT, the output frequency, phase, amplitude,

基于Python编写的用于曲线拟合，最小二乘法(Based on Python for curve fitting, least squares method.)

这些代码可以用于产生一系列随机数，可以根据需要使用。(These codes can be used to generate a series of random numbers may be used as needed.)

weno计算阶跃函数 时间离散采取三阶RK法；使用五阶WENO方法计算函数在[-1，1]内的数值解。(weno calculation step function)

三次样条插值函数实现 运行后画出曲线图，并得到插值函数表达式。(spline3)

说明：  一般的最小二乘通常是一次拿到全部的数据， 对所有数据进行统一优化计算得到模型系数。递推最小二乘是以一种递推的方式计算最小二乘，每次使用最新的测量值，来不断更新模型系数。(General least squares usually get all the data at one time, and perform unified optimization calculations on all the data to get the model coefficients. Recursive least squares is to calculate the least squares in a recursive way, each time the latest measured value is used to continuously update the model coefficients.)

FFT快速傅里叶变换，用于数字信号处理，大大提高了运行速度，节省内存开销。C语言实现(FFT fast Fourier transform for digital signal processing, greatly improving the speed and save memory overhead. C language)