Class RandomSamplingFacetsCollector

Collects hits for subsequent faceting, using sampling if needed. Once you've run a search and collect hits into this, instantiate one of the Facets subclasses to do the facet counting. Note that this collector does not collect the scores of matching docs (i.e. Scores) is null.

If you require the original set of hits, you can call GetOriginalMatchingDocs(). Also, since the counts of the top-facets is based on the sampled set, you can amortize the counts by calling AmortizeFacetCounts(FacetResult, FacetsConfig, IndexSearcher).

Inheritance
System.Object
FacetsCollector
RandomSamplingFacetsCollector
Implements
Lucene.Net.Search.ICollector
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.ToString()
Namespace: Lucene.Net.Facet
Assembly: Lucene.Net.Facet.dll
Syntax
public class RandomSamplingFacetsCollector : FacetsCollector, ICollector

Constructors

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RandomSamplingFacetsCollector(Int32)

Constructor with the given sample size and default seed.

Declaration
public RandomSamplingFacetsCollector(int sampleSize)
Parameters
Type Name Description
System.Int32 sampleSize
See Also
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RandomSamplingFacetsCollector(Int32, Int64)

Constructor with the given sample size and seed.

Declaration
public RandomSamplingFacetsCollector(int sampleSize, long seed)
Parameters
Type Name Description
System.Int32 sampleSize

The preferred sample size. If the number of hits is greater than the size, sampling will be done using a sample ratio of sampling size / totalN. For example: 1000 hits, sample size = 10 results in samplingRatio of 0.01. If the number of hits is lower, no sampling is done at all

System.Int64 seed

The random seed. If 0 then a seed will be chosen for you.

Properties

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SamplingRate

Returns the sampling rate that was used.

Declaration
public virtual double SamplingRate { get; }
Property Value
Type Description
System.Double

Methods

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AmortizeFacetCounts(FacetResult, FacetsConfig, IndexSearcher)

Note: if you use a counting Facets implementation, you can amortize the sampled counts by calling this method. Uses the FacetsConfig and the Lucene.Net.Search.IndexSearcher to determine the upper bound for each facet value.

Declaration
public virtual FacetResult AmortizeFacetCounts(FacetResult res, FacetsConfig config, IndexSearcher searcher)
Parameters
Type Name Description
FacetResult res
FacetsConfig config
Lucene.Net.Search.IndexSearcher searcher
Returns
Type Description
FacetResult
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GetMatchingDocs()

Returns the sampled list of the matching documents. Note that a FacetsCollector.MatchingDocs instance is returned per segment, even if no hits from that segment are included in the sampled set.

Note: One or more of the FacetsCollector.MatchingDocs might be empty (not containing any hits) as result of sampling.

Note: TotalHits is copied from the original FacetsCollector.MatchingDocs, scores is set to null

Declaration
public override IList<FacetsCollector.MatchingDocs> GetMatchingDocs()
Returns
Type Description
System.Collections.Generic.IList<FacetsCollector.MatchingDocs>
Overrides
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GetOriginalMatchingDocs()

Returns the original matching documents.

Declaration
public virtual IList<FacetsCollector.MatchingDocs> GetOriginalMatchingDocs()
Returns
Type Description
System.Collections.Generic.IList<FacetsCollector.MatchingDocs>

Implements

Lucene.Net.Search.ICollector