阅读笔记001.《Parameter estimation for text analysis》- Gregor Heinrich 论文笔记

该论文注释21中,提及并简化了论文《Topic and role discovery in social networks with experiments on Enron and academic email》- A. McCallum, X. Wang & A. Corrada-Emmanuel.的式子:
P ( x d i , z d i ∣ x − d i , z − d i , w , α , β , a , r ) = P ( x d i , z d i , w d i ∣ x − d i , z − d i , w − d i , α , β , a , r ) P ( w d i ∣ x − d i , z − d i , w − d i , α , β , a , r ) ∝ P ( x , z , w ∣ α , β , a , r ) P ( x − d i , z − d i , w − d i ∣ α , β , a , r ) ∝ Γ ( α z d i + n a d x d i z d i ) Γ ( α z d i + n a d x d i z d i − 1 ) Γ ( β w d i + m z d i w d i ) Γ ( β w d i + m z d i w d i − 1 ) Γ ( ∑ t = 1 T ( α t + n a d x d i t ) ) Γ ( ∑ t = 1 T ( α t + n a d x d i t ) − 1 ) Γ ( ∑ v = 1 V ( β v + m z d i v ) ) Γ ( ∑ v = 1 V ( β v + m z d i v ) − 1 ) ∝ α z d i + n a d x d i z d i − 1 ∑ t = 1 T ( α t + n a d x d i ) − 1 β w d i + m z d i w d i − 1 ∑ v = 1 ( β v + m z d i v ) − 1 \begin{alignedat}{3} &P\left(x_{d i}, z_{d i} \mid \mathbf{x}_{-d i}, \mathbf{z}_{-d i}, \mathbf{w}, \alpha, \beta, \mathbf{a}, \mathbf{r}\right) \\ &= \frac{P\left(x_{d i}, z_{d i}, w_{d i} \mid \mathbf{x}_{-d i}, \mathbf{z}_{-d i}, \mathbf{w}_{-d i}, \alpha, \beta, \mathbf{a}, \mathbf{r}\right)}{P\left(w_{d i} \mid \mathbf{x}_{-d i}, \mathbf{z}_{-d i}, \mathbf{w}_{-d i}, \alpha, \beta, \mathbf{a}, \mathbf{r}\right)} \propto \frac{P(\mathbf{x}, \mathbf{z}, \mathbf{w} \mid \alpha, \beta, \mathbf{a}, \mathbf{r})}{P\left(\mathbf{x}_{-d i}, \mathbf{z}_{-d i}, \mathbf{w}_{-d i} \mid \alpha, \beta, \mathbf{a}, \mathbf{r}\right)} \\ &\propto\frac{\frac{\Gamma\left(\alpha_{z_{d i}}+n_{a_{d} x_{d i} z_{d i}}\right)}{\Gamma\left(\alpha_{z_{d i}}+n_{\left.a_{d} x_{d i} z_{d i}-1\right)}\right.} \frac{\Gamma\left(\beta_{w_{d i}}+m_{z_{d i} w_{d i}}\right)}{\Gamma\left(\beta_{w_{d i}}+m_{\left.z_{d i} w_{d i}-1\right)}\right.} }{ \frac{\Gamma\left(\sum_{t=1}^{T}\left(\alpha_{t}+n_{a_{d} x_{d i} t}\right)\right)}{\Gamma\left(\sum_{t=1}^{T}\left(\alpha_{t}+n_{a_{d} x_{d i} t}\right)-1\right)} \frac{\Gamma\left(\sum_{v=1}^{V}\left(\beta_{v}+m_{z_{d i} v}\right)\right)}{\Gamma\left(\sum_{v=1}^{V}\left(\beta_{v}+m_{z_{d i} v}\right)-1\right)} }\propto\frac{\alpha_{z_{d i}}+n_{a_{d} x_{d i} z_{d i}}-1}{\sum_{t=1}^{T}\left(\alpha_{t}+n_{a_{d} x_{d i}}\right)-1} \frac{\beta_{w_{d i}}+m_{z_{d i} w_{d i}}-1}{\sum_{v=1}^{}\left(\beta_{v}+m_{z_{d i} v}\right)-1} \end{alignedat} P(xdi,zdixdi,zdi,w,α,β,a,r)=P(wdixdi,zdi,wdi,α,β,a,r)P(xdi,zdi,wdixdi,zdi,wdi,α,β,a,r)P(xdi,zdi,wdiα,β,a,r)P(x,z,wα,β,a,r)Γ(t=1T(αt+nadxdit)1)Γ(t=1T(αt+nadxdit))Γ(v=1V(βv+mzdiv)1)Γ(v=1V(βv+mzdiv))Γ(αzdi+nadxdizdi1)Γ(αzdi+nadxdizdi)Γ(βwdi+mzdiwdi1)Γ(βwdi+mzdiwdi)t=1T(αt+nadxdi)1αzdi+nadxdizdi1v=1(βv+mzdiv)1βwdi+mzdiwdi1

具体是将其简化成:
p ( z i ∣ z ⃗ ¬ i , w ⃗ ¬ i ) = p ( z i , w i ∣ z ⃗ ¬ i , w ⃗ ¬ i ) / p ( w i ∣ z ⃗ ¬ i , w ⃗ ¬ i ) ∝ p ( z ⃗ , w ⃗ ) / p ( z ⃗ ¬ i , w ⃗ ¬ i ) p(z_{i} \mid \vec{z}_{\neg i}, \vec{w}_{\neg i})=p(z_{i}, w_{i} \mid \vec{z}_{\neg i}, \vec{w}_{\neg i}) / p(w_{i} \mid \vec{z}_{\neg i}, \vec{w}_{\neg i}) \propto p(\vec{z}, \vec{w}) / p(\vec{z}_{\neg i}, \vec{w}_{\neg i}) p(ziz ¬i,w ¬i)=p(zi,wiz ¬i,w ¬i)/p(wiz ¬i,w ¬i)p(z ,w )/p(z ¬i,w ¬i)
但这个简化写法似乎有误,应为:
p ( z i ∣ z ⃗ ¬ i , w ⃗ ) = p ( z i , w i ∣ z ⃗ ¬ i , w ⃗ ¬ i ) / p ( w i ∣ z ⃗ ¬ i , w ⃗ ¬ i ) ∝ p ( z ⃗ , w ⃗ ) / p ( z ⃗ ¬ i , w ⃗ ¬ i ) p(z_{i} \mid \vec{z}_{\neg i}, \vec{w})=p(z_{i}, w_{i} \mid \vec{z}_{\neg i}, \vec{w}_{\neg i}) / p(w_{i} \mid \vec{z}_{\neg i}, \vec{w}_{\neg i}) \propto p(\vec{z}, \vec{w}) / p(\vec{z}_{\neg i}, \vec{w}_{\neg i}) p(ziz ¬i,w )=p(zi,wiz ¬i,w ¬i)/p(wiz ¬i,w ¬i)p(z ,w )/p(z ¬i,w ¬i)

以及,本人对相关公式的推演草稿(未做整理)暂存如下:

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转载自blog.csdn.net/yocencyy/article/details/113401243