public static


public static
Zend_Search_Lucene_Search_Similarity

#
getDefault( )
Return the default Similarity implementation used by indexing and search
code.
Return the default Similarity implementation used by indexing and search
code.
Returns

abstract public
float

#
lengthNorm( string $fieldName, integer $numTokens )
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.
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 implemenations of this method
usually return smaller values when 'numTokens' is large, and larger values when
'numTokens' is small.
That these values are computed under IndexWriter::addDocument(Document) and
stored then using encodeNorm(float). Thus they have limited precision, and
documents must be reindexed if this method is altered.
fieldName  name of field numTokens  the total number of tokens contained in
fields named 'fieldName' of 'doc'. Returns a normalization factor for hits on
this field of this document
Parameters
 $fieldName
string $fieldName
 $numTokens
integer $numTokens
Returns
float

abstract public
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.
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 Returns a
normalization factor for query weights
Parameters
 $sumOfSquaredWeights
float $sumOfSquaredWeights
Returns
float

public static
float

#
decodeNorm( integer $byte )
Decodes a normalization factor stored in an index.
Decodes a normalization factor stored in an index.
Parameters
Returns
float

public static
integer

#
encodeNorm( float $f )
Encodes a normalization factor for storage in an index.
Encodes a normalization factor for storage in an index.
The encoding uses a fivebit exponent and threebit mantissa, 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.
Parameters
Returns
integer

abstract public
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(Term, Searcher) factor for each term in the
query and these products are then summed to form the initial score for a
document.
Computes a score factor based on a term or phrase's frequency in a document.
This value is multiplied by the 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 'freq' is
large, and smaller values when 'freq' is small.
freq  the frequency of a term within a document Returns a score factor based
on a term's withindocument frequency
Parameters
Returns
float

abstract public
float

#
sloppyFreq( integer $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).
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 Returns the
frequency increment for this match
Parameters
 $distance
integer $distance
Returns
float

public
a

#
idf( mixed $input, Zend_Search_Lucene_Interface $reader )
Computes a score factor for a simple term or a phrase.
Computes a score factor for a simple term or a phrase.
The default implementation is: return idfFreq(searcher.docFreq(term),
searcher.maxDoc());
input  the term in question or array of terms reader  reader the document
collection being searched Returns a score factor for the term
Parameters
Returns
a score factor for the term

abstract public
float

#
idfFreq( integer $docFreq, integer $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.
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
implemenations 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 Returns a score factor based on the term's
document frequency
Parameters
 $docFreq
integer $docFreq
 $numDocs
integer $numDocs
Returns
float

abstract public
float

#
coord( integer $overlap, integer $maxOverlap )
Computes a score factor based on the fraction of all query terms that a
document contains. This value is multiplied into scores.
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 implemenations 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 Returns a score factor based on term overlap
with the query
Parameters
 $overlap
integer $overlap
 $maxOverlap
integer $maxOverlap
Returns
float
