Probabilistic context-free grammar - Wikipedia
It computes the total probability of all derivations that are consistent with a given sequence, based on some PCFG. This is equivalent to the probability of the PCFG generating the sequence, and is …
Accurate parsing requires modifications to the basic PCFG model: refining the nonterminals, relaxing the independence assumptions by including grandparent information, modeling word-word …
A PCFG is consistent if all eigenvalues of M have magnitude less than one (the spectral radius is less than one). If some eigenvalue has magni-tude greater than one, and all nonterminals are reachable …
Probabilistic Context-Free Grammars (PCFGs) Complete Guide
May 23, 2025 · A Probabilistic Context-Free Grammars (PCFG) is just a CFG with its production rules modified to include probabilities. The likelihood of various rewritings is shown by these probabilities.
Probabilistic Context-Free Grammars - Springer
A probabilistic context-free grammar (PCFG) is obtained by specifying a probability for each production for a nonterminal A in a CFG, such that a probability distribution exists over the set of productions for A.
nltk.grammar.PCFG
Jan 2, 2023 · PCFG productions use the ProbabilisticProduction class. PCFGs impose the constraint that the set of productions with any given left-hand-side must have probabilities that sum to 1 …
2 Example Thus the only parameters of a PCFG grammar are the rule probabilities, as in the following simple PCFG: (1) S → NP VP 1.0 NP → NP PP
PCFG – Knowledge and References – Taylor & Francis
A PCFG is an extension of a Context Free Grammar (CFG) in which the rules have probabilities associated with them. The goal of a PCFG is to get a probability distribution over derivations, and …
We now describe a second, very similar algorithm, which sums the probabilities for all parse trees for a given sentence, thereby calculating the probability of the sentence under the PCFG.
Probabilistic context-free grammar - Wikiwand
It computes the total probability of all derivations that are consistent with a given sequence, based on some PCFG. This is equivalent to the probability of the PCFG generating the sequence, and is …