App Entropy

用fortran 70实现数值积分，并实例计算了三个函数，导出了积分值和误差(The numerical integration is realized by FORTRAN 70, and three functions are calculated with examples. The integral values and errors are derived.)

实现复数运算符的重载，对C++初学者来说有一定的参考价值。(Complex operator overloading, C++ beginners a certain reference value . )

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)

一元线性回归，数值分析方面可参考(one yuan linear regression, numerical analysis can look at the reference)

PCA算法程序设计步骤： 1、去均值 2、计算协方差矩阵及其特征值和特征向量 3、计算协方差矩阵的特征值大于阈值的个数 4、降序排列特征值 5、去掉较小的特征值 6、去掉较大的特征值(一般没有这一步） 7、合并选择的特征值 8、选择相应的特征值和特征向量 9、计算白化矩阵 10、提取主分量 (PCA algorithm programming steps: 1 to mean 2, calculation of covariance matrix and its eigenvalues and eigenvectors 3, the calculation of covariance matrix eigenvalues greater than the threshold number of 4, in descending order of eigenvalue 5, remove the smaller eigenvalue 6, remove the larger eigenvalue (usually not this step) 7, the combined choice of eigenvalues 8, select the appropriate eigenvalues and eigenvectors 9, computing whitening matrix 10, principal component extraction)

C-means in 2 types. C=2

一个经典的基于排挤机制的小生境遗传算法程序 不错的 很好(A classic the niche genetic algorithm based on crowding mechanism of good is very good)

用C++编写的一维和二维快速傅里叶变换程序(Prepared with C++ one-dimensional and two-dimensional fast Fourier transform procedure)

C++程序求两点距离 可以点入坐标点(C++ program distance between two points)

一个在fluent udf中使用Compute_Force_and_Moment函数计算力的算例(An Example of Compute_Force_and_Moment Function in Fluent UDF)