joshua.decoder.hypergraph.GrammarBuilderWalkerFunction Class Reference

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List of all members.

Public Member Functions
	GrammarBuilderWalkerFunction (String goal)
	GrammarBuilderWalkerFunction (String goal, PrintStream out)
void	apply (HGNode node)
Grammar	getGrammar ()
Static Public Member Functions
static int	goalSymbol (HyperGraph hg)
Static Public Attributes
static final int	MAX_NTS = 500000
Private Member Functions
boolean	nodeHasGoalSymbol (HGNode node)
BilingualRule	getRuleWithSpans (HyperEdge edge, HGNode head)
Static Private Member Functions
static int	getLabelWithSpan (HGNode node)
static String	getLabelWithSpanAsString (HGNode node)
static int[]	getNewSource (boolean isGlue, HyperEdge edge)
static int[]	getNewTargetFromSource (int[] source)
static HGNode	getGoalSymbolNode (HGNode root)
Private Attributes
MemoryBasedBatchGrammar	grammar
PrintStream	outStream
int	goalSymbol
HashSet< Rule >	rules
Static Private Attributes
static HieroFormatReader	reader = new HieroFormatReader()
static final int	MAX_SENTENCE_LENGTH = 64

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Detailed Description

This walker function builds up a new context-free grammar by visiting each node in a hypergraph. For a quick overview, see Chris Dyer's 2010 NAACL paper "Two monlingual parses are better than one (synchronous parse)".

From a functional-programming point of view, this walker really wants to calculate a fold over the entire hypergraph: the initial value is an empty grammar, and as we visit each node, we add more rules to the grammar. After we have traversed the whole hypergraph, the resulting grammar will contain all rules needed for synchronous parsing.

These rules look just like the rules already present in the hypergraph, except that each non-terminal symbol is annotated with the span of its node.

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Constructor & Destructor Documentation

joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.GrammarBuilderWalkerFunction

(

String

goal

)

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joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.GrammarBuilderWalkerFunction	(	String	goal,
		PrintStream	out
	)

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Member Function Documentation

void joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.apply

(

HGNode

node

)

Implements joshua.decoder.hypergraph.WalkerFunction.

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static HGNode joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.getGoalSymbolNode

(

HGNode

root

)

[static, private]

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Grammar joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.getGrammar

(

)

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static int joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.getLabelWithSpan

(

HGNode

node

)

[static, private]

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static String joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.getLabelWithSpanAsString

(

HGNode

node

)

[static, private]

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static int [] joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.getNewSource	(	boolean	isGlue,
		HyperEdge	edge
	)		[static, private]

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static int [] joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.getNewTargetFromSource

(

int[]

source

)

[static, private]

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BilingualRule joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.getRuleWithSpans	(	HyperEdge	edge,
		HGNode	head
	)		[private]

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static int joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.goalSymbol

(

HyperGraph

hg

)

[static]

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boolean joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.nodeHasGoalSymbol

(

HGNode

node

)

[private]

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Member Data Documentation

int joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.goalSymbol [private]

MemoryBasedBatchGrammar joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.grammar [private]

final int joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.MAX_NTS = 500000 [static]

final int joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.MAX_SENTENCE_LENGTH = 64 [static, private]

PrintStream joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.outStream [private]

HieroFormatReader joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.reader = new HieroFormatReader() [static, private]

HashSet<Rule> joshua.decoder.hypergraph.GrammarBuilderWalkerFunction.rules [private]