Lucene.Net
3.0.3
Lucene.Net is a port of the Lucene search engine library, written in C# and targeted at .NET runtime users.
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Expert: Delegating scoring implementation. Useful in Query.GetSimilarity(Searcher) implementations, to override only certain methods of a Searcher's Similiarty implementation.. More...
Inherits Lucene.Net.Search.Similarity.
Inherited by Lucene.Net.Search.BooleanQuery.AnonymousClassSimilarityDelegator, and Lucene.Net.Search.FuzzyLikeThisQuery.FuzzyTermQuery.AnonymousSimilarityDelegator.
Public Member Functions | |
SimilarityDelegator (Similarity delegee) | |
Construct a Similarity that delegates all methods to another. | |
override float | ComputeNorm (System.String fieldName, FieldInvertState state) |
Compute the normalization value for a field, given the accumulated state of term processing for this field (see FieldInvertState). | |
override float | LengthNorm (System.String fieldName, int numTerms) |
Computes the normalization value for a field given the total number of terms contained in a field. These values, together with field boosts, are stored in an index and multipled into scores for hits on each field by the search code. | |
override float | QueryNorm (float sumOfSquaredWeights) |
Computes the normalization value for a query given the sum of the squared weights of each of the query terms. This value is then multipled into the weight of each query term. | |
override float | Tf (float freq) |
Computes a score factor based on a term or phrase's frequency in a document. This value is multiplied by the Idf(int, int) factor for each term in the query and these products are then summed to form the initial score for a document. | |
override float | SloppyFreq (int distance) |
Computes the amount of a sloppy phrase match, based on an edit distance. This value is summed for each sloppy phrase match in a document to form the frequency that is passed to Tf(float). | |
override float | Idf (int docFreq, int numDocs) |
Computes a score factor based on a term's document frequency (the number of documents which contain the term). This value is multiplied by the Tf(int) factor for each term in the query and these products are then summed to form the initial score for a document. | |
override float | Coord (int overlap, int maxOverlap) |
Computes a score factor based on the fraction of all query terms that a document contains. This value is multiplied into scores. | |
override float | ScorePayload (int docId, string fieldName, int start, int end, byte[] payload, int offset, int length) |
Public Member Functions inherited from Lucene.Net.Search.Similarity | |
virtual float | Tf (int freq) |
Computes a score factor based on a term or phrase's frequency in a document. This value is multiplied by the Idf(int, int) factor for each term in the query and these products are then summed to form the initial score for a document. | |
virtual IDFExplanation | IdfExplain (Term term, Searcher searcher) |
Computes a score factor for a simple term and returns an explanation for that score factor. | |
virtual IDFExplanation | IdfExplain (ICollection< Term > terms, Searcher searcher) |
Computes a score factor for a phrase. | |
virtual float | ScorePayload (int docId, System.String fieldName, int start, int end, byte[] payload, int offset, int length) |
Calculate a scoring factor based on the data in the payload. Overriding implementations are responsible for interpreting what is in the payload. Lucene makes no assumptions about what is in the byte array. The default implementation returns 1. | |
Additional Inherited Members | |
Static Public Member Functions inherited from Lucene.Net.Search.Similarity | |
static float | DecodeNorm (byte b) |
Decodes a normalization factor stored in an index. | |
static float[] | GetNormDecoder () |
Returns a table for decoding normalization bytes. | |
static byte | EncodeNorm (float f) |
Encodes a normalization factor for storage in an index. | |
Public Attributes inherited from Lucene.Net.Search.Similarity | |
const int | NO_DOC_ID_PROVIDED = - 1 |
Protected Member Functions inherited from Lucene.Net.Search.Similarity | |
Similarity () | |
Properties inherited from Lucene.Net.Search.Similarity | |
static Similarity | Default [get, set] |
Gets or sets the default Similarity implementation used by indexing and search code. This is initially an instance of DefaultSimilarity. | |
Expert: Delegating scoring implementation. Useful in Query.GetSimilarity(Searcher) implementations, to override only certain methods of a Searcher's Similiarty implementation..
Definition at line 29 of file SimilarityDelegator.cs.
Lucene.Net.Search.SimilarityDelegator.SimilarityDelegator | ( | Similarity | delegee | ) |
Construct a Similarity that delegates all methods to another.
delegee | the Similarity implementation to delegate to |
Definition at line 35 of file SimilarityDelegator.cs.
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virtual |
Compute the normalization value for a field, given the accumulated state of term processing for this field (see FieldInvertState).
Implementations should calculate a float value based on the field state and then return that value.
For backward compatibility this method by default calls LengthNorm(String, int) passing FieldInvertState.Length as the second argument, and then multiplies this value by FieldInvertState.Boost.
WARNING: This API is new and experimental and may suddenly change.
field | field name |
state | current processing state for this field |
Reimplemented from Lucene.Net.Search.Similarity.
Definition at line 40 of file SimilarityDelegator.cs.
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virtual |
Computes a score factor based on the fraction of all query terms that a document contains. This value is multiplied into scores.
The presence of a large portion of the query terms indicates a better match with the query, so implementations of this method usually return larger values when the ratio between these parameters is large and smaller values when the ratio between them is small.
overlap | the number of query terms matched in the document |
maxOverlap | the total number of terms in the query |
Implements Lucene.Net.Search.Similarity.
Definition at line 70 of file SimilarityDelegator.cs.
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virtual |
Computes a score factor based on a term's document frequency (the number of documents which contain the term). This value is multiplied by the Tf(int) factor for each term in the query and these products are then summed to form the initial score for a document.
Terms that occur in fewer documents are better indicators of topic, so implementations of this method usually return larger values for rare terms, and smaller values for common terms.
docFreq | the number of documents which contain the term |
numDocs | the total number of documents in the collection |
Implements Lucene.Net.Search.Similarity.
Definition at line 65 of file SimilarityDelegator.cs.
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virtual |
Computes the normalization value for a field given the total number of terms contained in a field. These values, together with field boosts, are stored in an index and multipled into scores for hits on each field by the search code.
Matches in longer fields are less precise, so implementations of this method usually return smaller values when numTokens
is large, and larger values when numTokens
is small.
Note that the return values are computed under Lucene.Net.Index.IndexWriter.AddDocument(Lucene.Net.Documents.Document) and then stored using EncodeNorm(float). Thus they have limited precision, and documents must be re-indexed if this method is altered.
fieldName | the name of the field |
numTokens | the total number of tokens contained in fields named fieldName of doc. |
a normalization factor for hits on this field of this document
Implements Lucene.Net.Search.Similarity.
Definition at line 45 of file SimilarityDelegator.cs.
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virtual |
Computes the normalization value for a query given the sum of the squared weights of each of the query terms. This value is then multipled into the weight of each query term.
This does not affect ranking, but rather just attempts to make scores from different queries comparable.
sumOfSquaredWeights | the sum of the squares of query term weights |
Implements Lucene.Net.Search.Similarity.
Definition at line 50 of file SimilarityDelegator.cs.
override float Lucene.Net.Search.SimilarityDelegator.ScorePayload | ( | int | docId, |
string | fieldName, | ||
int | start, | ||
int | end, | ||
byte[] | payload, | ||
int | offset, | ||
int | length | ||
) |
Definition at line 75 of file SimilarityDelegator.cs.
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virtual |
Computes the amount of a sloppy phrase match, based on an edit distance. This value is summed for each sloppy phrase match in a document to form the frequency that is passed to Tf(float).
A phrase match with a small edit distance to a document passage more closely matches the document, so implementations of this method usually return larger values when the edit distance is small and smaller values when it is large.
distance | the edit distance of this sloppy phrase match |
Implements Lucene.Net.Search.Similarity.
Definition at line 60 of file SimilarityDelegator.cs.
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virtual |
Computes a score factor based on a term or phrase's frequency in a document. This value is multiplied by the Idf(int, int) factor for each term in the query and these products are then summed to form the initial score for a document.
Terms and phrases repeated in a document indicate the topic of the document, so implementations of this method usually return larger values when freq
is large, and smaller values when freq
is small.
freq | the frequency of a term within a document |
Implements Lucene.Net.Search.Similarity.
Definition at line 55 of file SimilarityDelegator.cs.