type ProjectiveDependencyParser
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object --+
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ProjectiveDependencyParser
A projective, rule-based, dependency parser. A
ProjectiveDependencyParser is created with a DependencyGrammar, a set of
productions specifying word-to-word dependency relations. The parse()
method will then return the set of all parses, in tree representation,
for a given input sequence of tokens. Each parse must meet the
requirements of the both the grammar and the projectivity constraint
which specifies that the branches of the dependency tree are not allowed
to cross. Alternatively, this can be understood as stating that each
parent node and its children in the parse tree form a continuous
substring of the input sequence.
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__init__(self,
dependency_grammar)
Create a new ProjectiveDependencyParser, from a word-to-word
dependency grammar DependencyGrammar. |
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a list of tree
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parse(self,
tokens)
Performs a projective dependency parse on the list of tokens using a
chart-based, span-concatenation algorithm similar to Eisner (1996). |
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__init__(self,
dependency_grammar)
(Constructor)
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Create a new ProjectiveDependencyParser, from a word-to-word
dependency grammar DependencyGrammar.
- Parameters:
dependency_grammar (A DependencyGrammar.) - A word-to-word relation dependencygrammar. - Overrides:
object.__init__
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Performs a projective dependency parse on the list of tokens using a
chart-based, span-concatenation algorithm similar to Eisner (1996).
- Parameters:
tokens (a list of String) - The list of input tokens. - Returns: a
list of tree
- A list of parse trees.
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Concatenates the two spans in whichever way possible. This includes
rightward concatenation (from the leftmost word of the leftmost span to
the rightmost word of the rightmost span) and leftward concatenation
(vice-versa) between adjacent spans. Unlike Eisner's presentation of
span concatenation, these spans do not share or pivot on a particular
word/word-index.
return: A list of new spans formed through concatenation. rtype: A
list of DependencySpan
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