Logistic回归主要目的是寻找一个非线性sigmoid的最佳拟合参数，采用梯度上升算法可以达到局部的最优化-The main purpose of Logistic regression is to find the best fitting parameters of a nonlinear sigmoid, and the gradient ascent algorithm can be used to achieve the local optimization.

一个好的拟合算法，可能拟合直线、园、椭圆函数-Best-fitting line, circle and ellipse

用EM算法求解高斯混合模型并可视化，数据是男女生的身高分布，前提是初始化男女生身高各自的均值和方差和比例，然后由EM算法求解，男女生身高的均值方差，以拟合数据。(The EM algorithm is used to solve the Gauss mixture model and visualize. The data is the height distribution of male and female. The premise is to initialize the mean, v