nltk.InsideChartParser
¶
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class
nltk.
InsideChartParser
(grammar, beam_size=0, trace=0)[source]¶ A bottom-up parser for
PCFG
grammars that tries edges in descending order of the inside probabilities of their trees. The “inside probability” of a tree is simply the probability of the entire tree, ignoring its context. In particular, the inside probability of a tree generated by production p with children c[1], c[2], ..., c[n] is P(p)P(c[1])P(c[2])...P(c[n]); and the inside probability of a token is 1 if it is present in the text, and 0 if it is absent.This sorting order results in a type of lowest-cost-first search strategy.
Methods¶
__init__ (grammar[, beam_size, trace]) |
Create a new BottomUpProbabilisticChartParser , that uses grammar to parse texts. |
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grammar () |
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parse (tokens) |
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parse_all (sent, *args, **kwargs) |
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parse_one (sent, *args, **kwargs) |
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parse_sents (sents, *args, **kwargs) |
Apply self.parse() to each element of sents . |
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sort_queue (queue, chart) |
Sort the given queue of edges, in descending order of the inside probabilities of the edges’ trees. | ||
trace ([trace]) |
Set the level of tracing output that should be generated when parsing a text. |