FFT842

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)

三次样条曲线拟合代码，先训练，后差值，计算非常准确(Three times spline curve fitting, the first training, and after, computation is very accurate)

算术编码是用符号的概率和它的编码间隔两俩个基本参数来描述的。算术编码可以是静态的或是自适应的。(Arithmetic coding to both of two basic parameters to describe the probability of the symbol and its coding interval. Arithmetic coding can be static or adaptive.)

差分进化算法，有测试函数，是遗传算法的改进算法，收敛快，精度高。(Differential evolution algorithm, a test function, is an improved genetic algorithm algorithm, fast convergence, high precision.)

将一些标准数值与非数值算法集中封装在几个DLL中,需要用时可在VB/Delphi/C#中分别调用,这里提供了3个小程序,分别用于线性方程组求根、计算行列式的值、矩阵求逆。(Some standard numerical and non-numerical algorithm focus on packaging in several DLL, it is necessary to use when in VB/Delphi/C# Call, respectively, this provides three small programs, respectively, for the roots of linear equations, calculation of the value of the determinant, matrix inversion.)

潮流计算，IEEE30节点的潮流计算，和牛顿法的程序报告 (power flow)

对于水轮机阀门开启、关闭的一瞬间，对于钢管有比较大的水击。该程序计算出了相对最大的水击压力。(For turbine valves opened, the closure of the moment, for a relatively large pipe water hammer. The program calculated the maximum relative pressure of water hammer.)

说明：  实现快速离散傅里叶变换，即FFT,很有用的程序(Fast discrete Fourier transform, namely, FFT, very useful program)

基于D2Q9模型的LBM程序，用于计算方腔驱动流，对应何亚玲《格子Boltzmann方法的理论及应用》一书的源码(LBM D2Q9 model-based program used to calculate the square cavity driven flow, which corresponds He Yaling " Lattice Boltzmann Method Theory and Applications," a source book)

提供函数能进行1维2维的FFT，输入输出的序列长度应为2的整数次方倍(Provides functions can be one-dimensional two-dimensional FFT, sequence length input and output should be an integer power of 2 times)