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多分类逻辑回归模型
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二分类逻辑回归模型
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第6章 最大熵模型
Last updated
4 years ago
假设Y的取值集合是${1, 2, \cdots, K}$，则
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\begin{aligned} P(Y=k|x) = \frac{\exp (w_k \cdot x)}{1+\sum_{k=1}^{K-1}exp(w_k \cdot x)} \\ P(Y=K) = \frac{1}{1+\sum_{k=1}^{K-1}exp(w_k \cdot x)} \end{aligned}
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其中$x \in R^{n+1}$，$w_k \in R^{n+1}$