chazhi

说明：  用于在数值分析中，对于离散点进行拉格朗日差值拟合(Lagrangian difference fitting)

最小二乘法寻找最佳函数匹配，用以数值计算，优化曲线(The least square method is used to find the best function matching for numerical calculation and curve optimization.)

对于PID算法给予了通俗易懂的讲解，有利于初学者快速掌握PID的要领(I give the PID algorithm the understandable explanation，which will help beginners to quickly master the PID essentials)

说明：  此程序为分段最小二乘算法曲线拟合,可对一模型进行分段拟合,增加准确性和精确度.(This program is sub-least-squares curve fitting algorithm can be fitted to a sub-model to increase the accuracy and precision.)

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)

说明：  用混合同余法生成两组伪随机数，利用投针试验求圆周率。软件：matlab。(Two groups of pseudo-random numbers are generated by the method of mixed congruence, and the circularity is calculated by the test of inserting needle. Software: MATLAB.)

空间数据扩边以后做fft并在频率域延拓，可用于求重磁异常(expansion of spatial data and FFT， in the frequency domain extension can be used to find the gravity and magnetic anomalies)

气泡上浮实验，基于fluent的二维模型(Bubble Floating Experiment)

格子玻尔兹曼 圆柱绕流 Python编写(lattice boltzmann flow around a cylinder, using Python. very fast because of numpy library)

线性方程组迭代解法,包括SOR，CG ，BICG等(linear system iteration solver)