The Similarity type exposes the following members.
Methods
| Name | Description | |
|---|---|---|
 | ComputeNorm | Compute the normalization value for a field, given the accumulated
state of term processing for this field (see {@link 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
{@link #LengthNorm(String, int)} passing
{@link FieldInvertState#GetLength()} as the second argument, and
then multiplies this value by {@link FieldInvertState#GetBoost()}.WARNING: This API is new and experimental and may
suddenly change. |
| Coord | 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.
|
 | DecodeNorm | Decodes a normalization factor stored in an index. |
| EncodeNorm | Encodes a normalization factor for storage in an index.
The encoding uses a three-bit mantissa, a five-bit exponent, and
the zero-exponent point at 15, thus
representing values from around 7x10^9 to 2x10^-9 with about one
significant decimal digit of accuracy. Zero is also represented.
Negative numbers are rounded up to zero. Values too large to represent
are rounded down to the largest representable value. Positive values too
small to represent are rounded up to the smallest positive representable
value.
|
| Equals | (Inherited from Object.) |
 | Finalize | Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
| GetDefault | Return the default Similarity implementation used by indexing and search
code.
This is initially an instance of {@link DefaultSimilarity}.
|
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetNormDecoder | Returns a table for decoding normalization bytes. |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| Idf(ICollection, Searcher) | Obsolete. Computes a score factor for a phrase.
The default implementation sums the {@link #Idf(Term,Searcher)} factor
for each term in the phrase.
|
| Idf(Int32, Int32) | 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
{@link #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.
|
| Idf(Term, Searcher) | Obsolete. Computes a score factor for a simple term.
The default implementation is:
return idf(searcher.docFreq(term), searcher.maxDoc());
Note that {@link Searcher#MaxDoc()} is used instead of
{@link Lucene.Net.Index.IndexReader#NumDocs()} because it is proportional to
{@link Searcher#DocFreq(Term)} , i.e., when one is inaccurate,
so is the other, and in the same direction.
|
| idfExplain | Computes a score factor for a phrase.
The default implementation sums the idf factor for
each term in the phrase.
|
| IdfExplain | Computes a score factor for a simple term and returns an explanation
for that score factor.
The default implementation uses:
idf(searcher.docFreq(term), searcher.maxDoc());
Note that {@link Searcher#MaxDoc()} is used instead of
{@link Lucene.Net.Index.IndexReader#NumDocs()} because it is
proportional to {@link Searcher#DocFreq(Term)} , i.e., when one is
inaccurate, so is the other, and in the same direction.
|
| LengthNorm | 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  CopyC#numTokens CopyC#numTokens |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| QueryNorm | 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.
|
| ScorePayload(String, array<Byte>[]()[][], Int32, Int32) | Obsolete. 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.
|
| ScorePayload(Int32, String, Int32, Int32, array<Byte>[]()[][], Int32, Int32) | 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.
|
| SetDefault | Set the default Similarity implementation used by indexing and search
code.
|
| SloppyFreq | 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 {@link #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.
|
| Tf(Int32) | Computes a score factor based on a term or phrase's frequency in a
document. This value is multiplied by the {@link #Idf(Term, Searcher)}
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 CopyC#freq CopyC#freq |
| Tf(Single) | Computes a score factor based on a term or phrase's frequency in a
document. This value is multiplied by the {@link #Idf(Term, Searcher)}
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 CopyC#freq CopyC#freq |
| ToString | (Inherited from Object.) |
