Package nltk_lite :: Package parse :: Module pchart :: Class InsideParse
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Type InsideParse

object --+            
         |            
    ParseI --+        
             |        
 AbstractParse --+    
                 |    
BottomUpChartParse --+
                     |
                    InsideParse


A bottom-up parser for PCFGs 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.
Method Summary
None sort_queue(self, queue, chart)
Sort the given queue of edges, in descending order of the inside probabilities of the edges' trees.
Inherited from BottomUpChartParse: __init__, get_parse_list, trace
Inherited from AbstractParse: get_parse, grammar, parse
Inherited from ParseI: get_parse_probs
Inherited from object: __delattr__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __str__

Method Details

sort_queue(self, queue, chart)

Sort the given queue of edges, in descending order of the inside probabilities of the edges' trees.
Parameters:
queue - The queue of Edges to sort. Each edge in this queue is an edge that could be added to the chart by the fundamental rule; but that has not yet been added.
           (type=list of Edge)
chart - The chart being used to parse the text. This chart can be used to provide extra information for sorting the queue.
           (type=Chart)
Returns:
None
Overrides:
nltk_lite.parse.pchart.BottomUpChartParse.sort_queue

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