HumHub Documentation (unofficial)

AbstractSimilarity
in package

AbstractYes
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category

Zend

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Table of Contents

Properties

$_defaultImpl  : AbstractSimilarity
The Similarity implementation used by default.
$_normTable  : array<string|int, mixed>
Cache of decoded bytes.

Methods

coord()  : float
Computes a score factor based on the fraction of all query terms that a document contains. This value is multiplied into scores.
decodeNorm()  : float
Decodes a normalization factor stored in an index.
encodeNorm()  : int
Encodes a normalization factor for storage in an index.
getDefault()  : AbstractSimilarity
Return the default Similarity implementation used by indexing and search code.
idf()  : float
Computes a score factor for a simple term or a phrase.
idfFreq()  : float
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.
lengthNorm()  : float
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.
queryNorm()  : float
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.
setDefault()  : void
Set the default Similarity implementation used by indexing and search code.
sloppyFreq()  : float
Computes the amount of a sloppy phrase match, based on an edit distance.
tf()  : float
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.
_floatToByte()  : float
Float to byte conversion

Properties

$_normTable

Cache of decoded bytes.

private static array<string|int, mixed> $_normTable = array(0 => 0.0, 1 => 5.820766E-10, 2 => 6.984919300000001E-10, 3 => 8.1490725E-10, 4 => 9.313226E-10, 5 => 1.1641532E-9, 6 => 1.3969839E-9, 7 => 1.6298145E-9, 8 => 1.8626451E-9, 9 => 2.3283064E-9, 10 => 2.7939677E-9, 11 => 3.259629E-9, 12 => 3.7252903E-9, 13 => 4.656613E-9, 14 => 5.5879354E-9, 15 => 6.519258E-9, 16 => 7.4505806E-9, 17 => 9.313226E-9, 18 => 1.1175871E-8, 19 => 1.3038516E-8, 20 => 1.4901161E-8, 21 => 1.8626451E-8, 22 => 2.2351742E-8, 23 => 2.6077032E-8, 24 => 2.9802322E-8, 25 => 3.7252903E-8, 26 => 4.4703484E-8, 27 => 5.2154064E-8, 28 => 5.960464500000001E-8, 29 => 7.4505806E-8, 30 => 8.940697E-8, 31 => 1.0430813E-7, 32 => 1.1920929E-7, 33 => 1.4901161E-7, 34 => 1.7881393E-7, 35 => 2.0861626E-7, 36 => 2.3841858E-7, 37 => 2.9802322E-7, 38 => 3.5762787E-7, 39 => 4.172325E-7, 40 => 4.7683716E-7, 41 => 5.9604645E-7, 42 => 7.1525574E-7, 43 => 8.34465E-7, 44 => 9.536743E-7, 45 => 1.1920929E-6, 46 => 1.4305115E-6, 47 => 1.66893E-6, 48 => 1.9073486E-6, 49 => 2.3841858E-6, 50 => 2.861023E-6, 51 => 3.33786E-6, 52 => 3.8146973E-6, 53 => 4.7683716E-6, 54 => 5.722046E-6, 55 => 6.67572E-6, 56 => 7.6293945E-6, 57 => 9.536743000000001E-6, 58 => 1.1444092E-5, 59 => 1.335144E-5, 60 => 1.5258789E-5, 61 => 1.9073486E-5, 62 => 2.2888184E-5, 63 => 2.670288E-5, 64 => 3.0517578E-5, 65 => 3.8146973E-5, 66 => 4.5776367E-5, 67 => 5.340576E-5, 68 => 6.1035156E-5, 69 => 7.6293945E-5, 70 => 9.1552734E-5, 71 => 0.00010681152, 72 => 0.00012207031, 73 => 0.00015258789, 74 => 0.00018310547, 75 => 0.00021362305, 76 => 0.00024414062, 77 => 0.00030517578, 78 => 0.00036621094, 79 => 0.0004272461, 80 => 0.00048828125, 81 => 0.00061035156, 82 => 0.0007324219, 83 => 0.0008544922, 84 => 0.0009765625, 85 => 0.0012207031, 86 => 0.0014648438, 87 => 0.0017089844, 88 => 0.001953125, 89 => 0.0024414062, 90 => 0.0029296875, 91 => 0.0034179688, 92 => 0.00390625, 93 => 0.0048828125, 94 => 0.005859375, 95 => 0.0068359375, 96 => 0.0078125, 97 => 0.009765625, 98 => 0.01171875, 99 => 0.013671875, 100 => 0.015625, 101 => 0.01953125, 102 => 0.0234375, 103 => 0.02734375, 104 => 0.03125, 105 => 0.0390625, 106 => 0.046875, 107 => 0.0546875, 108 => 0.0625, 109 => 0.078125, 110 => 0.09375, 111 => 0.109375, 112 => 0.125, 113 => 0.15625, 114 => 0.1875, 115 => 0.21875, 116 => 0.25, 117 => 0.3125, 118 => 0.375, 119 => 0.4375, 120 => 0.5, 121 => 0.625, 122 => 0.75, 123 => 0.875, 124 => 1.0, 125 => 1.25, 126 => 1.5, 127 => 1.75, 128 => 2.0, 129 => 2.5, 130 => 3.0, 131 => 3.5, 132 => 4.0, 133 => 5.0, 134 => 6.0, 135 => 7.0, 136 => 8.0, 137 => 10.0, 138 => 12.0, 139 => 14.0, 140 => 16.0, 141 => 20.0, 142 => 24.0, 143 => 28.0, 144 => 32.0, 145 => 40.0, 146 => 48.0, 147 => 56.0, 148 => 64.0, 149 => 80.0, 150 => 96.0, 151 => 112.0, 152 => 128.0, 153 => 160.0, 154 => 192.0, 155 => 224.0, 156 => 256.0, 157 => 320.0, 158 => 384.0, 159 => 448.0, 160 => 512.0, 161 => 640.0, 162 => 768.0, 163 => 896.0, 164 => 1024.0, 165 => 1280.0, 166 => 1536.0, 167 => 1792.0, 168 => 2048.0, 169 => 2560.0, 170 => 3072.0, 171 => 3584.0, 172 => 4096.0, 173 => 5120.0, 174 => 6144.0, 175 => 7168.0, 176 => 8192.0, 177 => 10240.0, 178 => 12288.0, 179 => 14336.0, 180 => 16384.0, 181 => 20480.0, 182 => 24576.0, 183 => 28672.0, 184 => 32768.0, 185 => 40960.0, 186 => 49152.0, 187 => 57344.0, 188 => 65536.0, 189 => 81920.0, 190 => 98304.0, 191 => 114688.0, 192 => 131072.0, 193 => 163840.0, 194 => 196608.0, 195 => 229376.0, 196 => 262144.0, 197 => 327680.0, 198 => 393216.0, 199 => 458752.0, 200 => 524288.0, 201 => 655360.0, 202 => 786432.0, 203 => 917504.0, 204 => 1048576.0, 205 => 1310720.0, 206 => 1572864.0, 207 => 1835008.0, 208 => 2097152.0, 209 => 2621440.0, 210 => 3145728.0, 211 => 3670016.0, 212 => 4194304.0, 213 => 5242880.0, 214 => 6291456.0, 215 => 7340032.0, 216 => 8388608.0, 217 => 10485760.0, 218 => 12582912.0, 219 => 14680064.0, 220 => 16777216.0, 221 => 20971520.0, 222 => 25165824.0, 223 => 29360128.0, 224 => 33554432.0, 225 => 41943040.0, 226 => 50331648.0, 227 => 58720256.0, 228 => 67108864.0, 229 => 83886080.0, 230 => 100663296.0, 231 => 117440512.0, 232 => 134217728.0, 233 => 167772160.0, 234 => 201326592.0, 235 => 234881024.0, 236 => 268435456.0, 237 => 335544320.0, 238 => 402653184.0, 239 => 469762048.0, 240 => 536870910.0, 241 => 671088640.0, 242 => 805306370.0, 243 => 939524100.0, 244 => 1073741820.0, 245 => 1342177280.0, 246 => 1610612740.0, 247 => 1879048190.0, 248 => 2147483650.0, 249 => 2684354560.0, 250 => 3221225470.0, 251 => 3758096380.0, 252 => 4294967300.0, 253 => 5368709100.0, 254 => 6442450900.0, 255 => 7516192800.0)

Array of floats

Methods

coord()

Computes a score factor based on the fraction of all query terms that a document contains. This value is multiplied into scores.

public abstract coord(int $overlap, int $maxOverlap) : float

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 : int
$maxOverlap : int
Return values
float

decodeNorm()

Decodes a normalization factor stored in an index.

public static decodeNorm(int $byte) : float
Parameters
$byte : int
Return values
float

encodeNorm()

Encodes a normalization factor for storage in an index.

public static encodeNorm(float $f) : int

The encoding uses a five-bit exponent and three-bit 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
$f : float
Return values
int

idf()

Computes a score factor for a simple term or a phrase.

public idf(mixed $input, SearchIndexInterface $reader) : float

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
$input : mixed
$reader : SearchIndexInterface
Return values
float —

a score factor for the term

idfFreq()

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.

public abstract idfFreq(int $docFreq, int $numDocs) : float

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 : int
$numDocs : int
Return values
float

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.

public abstract lengthNorm(string $fieldName, int $numTokens) : float

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 re-indexed 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
$numTokens : int
Return values
float

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.

public abstract queryNorm(float $sumOfSquaredWeights) : float

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
Return values
float

sloppyFreq()

Computes the amount of a sloppy phrase match, based on an edit distance.

public abstract sloppyFreq(int $distance) : float

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 : int
Return values
float

tf()

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.

public abstract tf(float $freq) : float

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 within-document frequency

Parameters
$freq : float
Return values
float

_floatToByte()

Float to byte conversion

private static _floatToByte(float $f) : float
Parameters
$f : float
Return values
float 

        

        
    




    

    

                                

                

                                
    

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