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In computer science, the inside–outside algorithm is a way of re-estimating production probabilities in a probabilistic context-free grammar. It was introduced James K. Baker in 1979 as a generalization of the forward–backward algorithm for parameter estimation on hidden Markov models to stochastic context-free grammars. It is used to compute expectations, for example as part of the expectation–maximization algorithm (an unsupervised learning algorithm). ==Inside and outside probabilities== The inside probability is the total probability of generating words , given the root nonterminal and a grammar : : The outside probability is the total probability of beginning with the start symbol and generating the nonterminal and all the words outside , given a grammar :〔 : 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Inside–outside algorithm」の詳細全文を読む スポンサード リンク
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