> For the complete documentation index, see [llms.txt](https://windmising.gitbook.io/lihang-tongjixuexifangfa/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://windmising.gitbook.io/lihang-tongjixuexifangfa/em/1.md).

# 算法过程

令$$\theta^{(i)}$$为第i次迭代参数$$\theta$$的估计值。

**输入：**\
1\. 选择参数的初值$$\theta^{(0)}$$开始迭代。\
2\. E步：假设当前已知$$\theta^{(i)}$$，此次为第i+1次迭代。计算期望：

$$
Q(\theta, \theta^{(i)}) = \sum\_z\log P(Y,Z|\theta)P(Z|Y, \theta^{(i)})
$$

1. M步：求使$$Q(\theta, \theta^{(i)})$$极大化的$$\theta^{(i+1)}$$  

   $$
   \theta^{(i+1)} = \arg\max\_{\theta}Q(\theta, \theta^{(i)})
   $$
2. 重复2、3步，直至收敛，即$$\theta^{(i+1)}$$和$$\theta^{(i)}$$的差别足够小。  


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