org.terrier.querying
Class ExpansionTerms

java.lang.Object
  org.terrier.querying.ExpansionTerms

Direct Known Subclasses:

DFRBagExpansionTerms

public abstract class ExpansionTerms
extends java.lang.Object

Base class for weighting term occurrences in feedback documents.

Since:

3.0

Author:

Craig Macdonald

Nested Class Summary

static class

ExpansionTerms.ExpansionTerm This class implements a data structure for a term in the top-retrieved documents.

Field Summary

protected static java.util.Comparator<ExpansionTerms.ExpansionTerm>	EXPANSIONTERM_DESC_SCORE_SORTER
protected static org.apache.log4j.Logger	logger
protected QueryExpansionModel	model
protected gnu.trove.TIntDoubleHashMap	originalTermFreqs The frequency of each query term in the original query.
protected gnu.trove.TIntObjectHashMap<java.lang.String>	originalTermids The original query terms.

Constructor Summary

protected

ExpansionTerms()

Method Summary

abstract SingleTermQuery[]	getExpandedTerms(int numberOfExpandedTerms) Get the most informative terms for the expanded set.
abstract int	getNumberOfUniqueTerms() Returns the number of terms being considered
abstract void	insertDocument(FeedbackDocument doc) Add a single document to be considered for expanding the query
void	setModel(QueryExpansionModel m) Set query expansion model
void	setOriginalQueryTerms(MatchingQueryTerms query) Set the original query terms.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final org.apache.log4j.Logger logger

EXPANSIONTERM_DESC_SCORE_SORTER

protected static final java.util.Comparator<ExpansionTerms.ExpansionTerm> EXPANSIONTERM_DESC_SCORE_SORTER

originalTermids

protected gnu.trove.TIntObjectHashMap<java.lang.String> originalTermids

The original query terms. Used only for Conservative Query Expansion, where no terms are added to the query, only the existing ones are reweighted.

originalTermFreqs

protected gnu.trove.TIntDoubleHashMap originalTermFreqs

The frequency of each query term in the original query. Currently used by RM3 only.

model

protected QueryExpansionModel model

Constructor Detail

ExpansionTerms

protected ExpansionTerms()

Method Detail

setOriginalQueryTerms

public void setOriginalQueryTerms(MatchingQueryTerms query)

Set the original query terms.

Parameters:

query - The original query.

insertDocument

public abstract void insertDocument(FeedbackDocument doc)
                             throws java.io.IOException

Add a single document to be considered for expanding the query

Throws:

java.io.IOException

getExpandedTerms

public abstract SingleTermQuery[] getExpandedTerms(int numberOfExpandedTerms)

Get the most informative terms for the expanded set.

Parameters:

numberOfExpandedTerms - - number of terms to get.

Returns:

weighted query terms

setModel

public void setModel(QueryExpansionModel m)

Set query expansion model

Parameters:

m -

getNumberOfUniqueTerms

public abstract int getNumberOfUniqueTerms()

Returns the number of terms being considered