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firtex::search::CSimilarity类参考

#include <Similarity.h>

继承图，类firtex::search::CSimilarity

firtex::search::CDefaultSimilarity 所有成员的列表。

公有成员

 CSimilarity (void)
virtual ~CSimilarity (void)
virtual float tf (int freq)
virtual float tf (float freq)=0
virtual float idf (CTerm *term, CSearcher *searcher)
virtual float idf (freq_t docFreq, count_t numDocs)=0
virtual float sloppyFreq (int distance)=0
virtual float lengthNorm (count_t numTerms)=0
virtual float queryNorm (float sumOfSquaredWeights)=0
virtual float coord (int overlap, int maxOverlap)=0

静态公有成员

CSimilarity * getDefault ()
void setDefault (CSimilarity *pDefault)
float decodeNorm (byte b)
byte encodeNorm (float f)

静态保护成员

void initNormTable ()

静态保护属性

float NORM_TABLE [256]
bool m_bNormTableInited

构造及析构函数文档

firtex::search::CSimilarity::CSimilarity (  void   ) 
 

virtual firtex::search::CSimilarity::~CSimilarity (  void   )  [virtual]
 

成员函数文档

virtual float firtex::search::CSimilarity::coord (  int  overlap,
int  maxOverlap
)  [pure 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.

参数:
overlap the number of query terms matched in the document
maxOverlap the total number of terms in the query
返回:
a score factor based on term overlap with the query

在firtex::search::CDefaultSimilarity内被实现。

float firtex::search::CSimilarity::decodeNorm (  byte  b  )  [inline, static]
 

Decodes a normalization factor stored in an index.

参见:
encodeNorm(float)

byte firtex::search::CSimilarity::encodeNorm (  float  f  )  [inline, static]
 

CSimilarity* firtex::search::CSimilarity::getDefault (   )  [static]
 

virtual float firtex::search::CSimilarity::idf (  freq_t  docFreq,
count_t  numDocs
)  [pure virtual]
 

计算idf

参数:
docFreq 文档频率
numDocs 文档总数
返回:
idf值

在firtex::search::CDefaultSimilarity内被实现。

virtual float firtex::search::CSimilarity::idf (  CTerm *  term,
CSearcher *  searcher
)  [virtual]
 

计算idf

参数:
term Term
searcher Index Searcher
返回:
idf值

void firtex::search::CSimilarity::initNormTable (   )  [static, protected]
 

virtual float firtex::search::CSimilarity::lengthNorm (  count_t  numTerms  )  [pure virtual]
 

在firtex::search::CDefaultSimilarity内被实现。

virtual float firtex::search::CSimilarity::queryNorm (  float  sumOfSquaredWeights  )  [pure virtual]
 

在firtex::search::CDefaultSimilarity内被实现。

void firtex::search::CSimilarity::setDefault (  CSimilarity *  pDefault  )  [static]
 

virtual float firtex::search::CSimilarity::sloppyFreq (  int  distance  )  [pure 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.

参见:
CPhraseQuery::setSlop(int)
参数:
distance the edit distance of this sloppy phrase match
返回:
the frequency increment for this match

在firtex::search::CDefaultSimilarity内被实现。

virtual float firtex::search::CSimilarity::tf (  float  freq  )  [pure virtual]
 

计算tf

参数:
freq 词频
返回:
tf值

在firtex::search::CDefaultSimilarity内被实现。

virtual float firtex::search::CSimilarity::tf (  int  freq  )  [inline, virtual]
 

计算tf

参数:
freq 词频
返回:
tf值

成员数据文档

bool firtex::search::CSimilarity::m_bNormTableInited [static, protected]
 

float firtex::search::CSimilarity::NORM_TABLE[256] [static, protected]
 

Cache of decoded bytes.

该类的文档由以下文件生成：

http://www.firtex.org http://www.sourceforge.net/projects/firtex