org.aika.corpus

Class SearchNode

java.lang.Object

org.aika.corpus.SearchNode

All Implemented Interfaces:

Comparable<SearchNode>

public class SearchNode
extends Object
implements Comparable<SearchNode>

The SearchNode class represents a node in the binary search tree that is used to find the optimal interpretation for a given document. Each search node possess a refinement (simply a set of interpretation nodes). The two options that this search node examines are that the refinement will either part of the final interpretation or not. During each search step the activation values in all the neuron activations adjusted such that they reflect the interpretation of the current search path. When the search reaches the maximum depth of the search tree and no further refinements exists, a weight is computed evaluating the current search path. The search path with the highest weight is used to determine the final interpretation.

Before the search is started a set of initial refinements is generated from the conflicts within the document. In other words, if there are no conflicts in a given document, then no search is needed. In this case the final interpretation will simply be the set of all interpretation nodes. The initial refinements are then expanded, meaning all interpretation nodes that are consistent with this refinement are added to the refinement. The initial refinements are then propagated along the search path as refinement candidates.

Author:

Lukas Molzberger

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SearchNode.DebugState
static class	SearchNode.Weight

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	ENABLE_CACHING
SearchNode	excludedParent
int	id
static int	MAX_SEARCH_STEPS
Map<Activation,Activation.StateChange>	modifiedActs
SearchNode	selectedParent
long	visited

Constructor Summary

Constructors

Constructor and Description
SearchNode(Document doc, SearchNode selParent, SearchNode exclParent, Candidate c, int level)

Method Summary

Modifier and Type	Method and Description
void	changeState(Activation.Mode m)
void	collectResults(Collection<InterpretationNode> results)
boolean	compareNewState(SearchNode cachedNode)
int	compareTo(SearchNode sn)
void	dumpDebugState()
boolean	getDecision()
SearchNode	getParent()
String	pathToString(Document doc)
void	reconstructSelectedResult(Document doc)
static void	searchIterative(Document doc, SearchNode root) Searches for the best interpretation for the given document.
SearchNode.Weight	searchRecursive(Document doc) This algorithm is the recursive version of the interpretation search.
String	toString(Document doc)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAX_SEARCH_STEPS

public static int MAX_SEARCH_STEPS

ENABLE_CACHING

public static boolean ENABLE_CACHING

id

public int id

excludedParent

public SearchNode excludedParent

selectedParent

public SearchNode selectedParent

visited

public long visited

modifiedActs

public Map<Activation,Activation.StateChange> modifiedActs

Constructor Detail

SearchNode

public SearchNode(Document doc,
                  SearchNode selParent,
                  SearchNode exclParent,
                  Candidate c,
                  int level)

Method Detail

compareNewState

public boolean compareNewState(SearchNode cachedNode)

collectResults

public void collectResults(Collection<InterpretationNode> results)

reconstructSelectedResult

public void reconstructSelectedResult(Document doc)

dumpDebugState

public void dumpDebugState()

searchRecursive

public SearchNode.Weight searchRecursive(Document doc)

This algorithm is the recursive version of the interpretation search. Its perhaps easier to read than the iterative version.

searchIterative

public static void searchIterative(Document doc,
                                   SearchNode root)

Searches for the best interpretation for the given document. This implementation of the algorithm is iterative to prevent stack overflow errors from happening. Depending on the document the search tree might be getting very deep.

Parameters:

doc -

root -

pathToString

public String pathToString(Document doc)

toString

public String toString(Document doc)

changeState

public void changeState(Activation.Mode m)

compareTo

public int compareTo(SearchNode sn)

Specified by:

compareTo in interface Comparable<SearchNode>

getParent

public SearchNode getParent()

getDecision

public boolean getDecision()