1. word latent topic estimation device for estimating a probabilistic word latent topic sequentially each time a document is added, comprising: a document data addition unit that inputs a document including one or more words; a level setting unit that sets the number of topics at each level in accordance with a hierarchical structure of topics for hierarchically estimating a latent topic of a word, the hierarchical structure constituted with a preset width and a preset depth; a higher-level constraint creation unit that creates a higher-level constraint for a word in the document on the basis of a result of topic estimation at a given level, the higher-level constraint indicating an identifier of a topic that is likely to be assigned to the word and the probability of the word being assigned to the topic; and a higher-level-constraint-attached topic estimation unit which, when estimating the probability of each word in the input document being assigned to each topic, refers to the higher-level constraint which is created by the higher-level constraint creation unit and uses the probability of the word being assigned to a parent topic at a higher level as a weight to perform estimation processing for a lower-level topic.
1. word latent topic estimation device for estimating a probabilistic word latent topic sequentially each time a document is added, comprising: a document data addition unit that inputs a document including one or more words; a level setting unit that sets the number of topics at each level in accordance with a hierarchical structure of topics for hierarchically estimating a latent topic of a word, the hierarchical structure constituted with a preset width and a preset depth; a higher-level constraint creation unit that creates a higher-level constraint for a word in the document on the basis of a result of topic estimation at a given level, the higher-level constraint indicating an identifier of a topic that is likely to be assigned to the word and the probability of the word being assigned to the topic; and a higher-level-constraint-attached topic estimation unit which, when estimating the probability of each word in the input document being assigned to each topic, refers to the higher-level constraint which is created by the higher-level constraint creation unit and uses the probability of the word being assigned to a parent topic at a higher level as a weight to perform estimation processing for a lower-level topic. 3. The word latent topic estimation device according to claim 1 , further comprising an initial value update unit which, after the higher-level-constraint-attached topic estimation unit performs hierarchical topic estimation, computes the amount of computation when the current initial value of the number of topics is used without change and the amount of computation when the initial value of the number of topics is reduced and, when the difference between the amounts of computation is greater than a predetermined threshold value, reduces the initial value of the number of topics.