Dirichlet混合样本的EM算法与动态聚类算法比较

Dirichlet distribution is a kind of continuous multivariate probability distribution with positive parameter vectors, which is widely used in proportional structure problems. Expectation maximization (EM) algorithm and dynamical clustering algorithm of Dirichlet mixture samples are presented, their mathematical process is deduced, and the iteration steps of the algorithms are given. Then, using digital simulation experiments, the clustering effects of the two machine learning algorithms with Dirichlet samples are compared. By calculating six evaluation factors which are log-likelihood function value, program running time, convergence iteration times, clustering accuracy, true positive rate (TPR) and false positive rate (FPR), the simulation results show that EM algorithm has higher clustering accuracy but lower operational efficiency, while dynamical clustering algorithm has higher operational efficiency but loses some clustering accuracy. Therefore, in practical application, it is suggested to weigh the relative requirements of accuracy and operational efficiency before selecting a suitable algorithm to cluster Dirichlet samples.