xapian-core
1.4.27
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Public Types | |
enum | failmode { NONE, CLONE } |
Public Types inherited from Xapian::Weight | |
enum | type_smoothing { TWO_STAGE_SMOOTHING = 1, DIRICHLET_SMOOTHING = 2, ABSOLUTE_DISCOUNT_SMOOTHING = 3, JELINEK_MERCER_SMOOTHING = 4, DIRICHLET_PLUS_SMOOTHING = 5 } |
Type of smoothing to use with the Language Model Weighting scheme. More... | |
Public Member Functions | |
ExceptionalWeight (failmode fail_) | |
string | name () const override |
Return the name of this weighting scheme. More... | |
Weight * | clone () const override |
Clone this object. More... | |
void | init (double) override |
Allow the subclass to perform any initialisation it needs to. More... | |
double | get_sumpart (Xapian::termcount, Xapian::termcount, Xapian::termcount) const override |
Calculate the weight contribution for this object's term to a document. More... | |
double | get_maxpart () const override |
Return an upper bound on what get_sumpart() can return for any document. More... | |
double | get_sumextra (Xapian::termcount, Xapian::termcount) const override |
Calculate the term-independent weight component for a document. More... | |
double | get_maxextra () const override |
Return an upper bound on what get_sumextra() can return for any document. More... | |
Public Member Functions inherited from Xapian::Weight | |
Weight () | |
Default constructor, needed by subclass constructors. More... | |
virtual | ~Weight () |
Virtual destructor, because we have virtual methods. More... | |
virtual std::string | serialise () const |
Return this object's parameters serialised as a single string. More... | |
virtual Weight * | unserialise (const std::string &serialised) const |
Unserialise parameters. More... | |
Public Attributes | |
failmode | fail |
Additional Inherited Members | |
Protected Types inherited from Xapian::Weight | |
enum | stat_flags { COLLECTION_SIZE = 1, RSET_SIZE = 2, AVERAGE_LENGTH = 4, TERMFREQ = 8, RELTERMFREQ = 16, QUERY_LENGTH = 32, WQF = 64, WDF = 128, DOC_LENGTH = 256, DOC_LENGTH_MIN = 512, DOC_LENGTH_MAX = 1024, WDF_MAX = 2048, COLLECTION_FREQ = 4096, UNIQUE_TERMS = 8192, TOTAL_LENGTH = COLLECTION_SIZE | AVERAGE_LENGTH } |
Stats which the weighting scheme can use (see need_stat()). More... | |
Protected Member Functions inherited from Xapian::Weight | |
void | need_stat (stat_flags flag) |
Tell Xapian that your subclass will want a particular statistic. More... | |
Weight (const Weight &) | |
Don't allow copying. More... | |
Xapian::doccount | get_collection_size () const |
The number of documents in the collection. More... | |
Xapian::doccount | get_rset_size () const |
The number of documents marked as relevant. More... | |
Xapian::doclength | get_average_length () const |
The average length of a document in the collection. More... | |
Xapian::doccount | get_termfreq () const |
The number of documents which this term indexes. More... | |
Xapian::doccount | get_reltermfreq () const |
The number of relevant documents which this term indexes. More... | |
Xapian::termcount | get_collection_freq () const |
The collection frequency of the term. More... | |
Xapian::termcount | get_query_length () const |
The length of the query. More... | |
Xapian::termcount | get_wqf () const |
The within-query-frequency of this term. More... | |
Xapian::termcount | get_doclength_upper_bound () const |
An upper bound on the maximum length of any document in the shard. More... | |
Xapian::termcount | get_doclength_lower_bound () const |
A lower bound on the minimum length of any document in the shard. More... | |
Xapian::termcount | get_wdf_upper_bound () const |
An upper bound on the wdf of this term in the shard. More... | |
Xapian::totallength | get_total_length () const |
Total length of all documents in the collection. More... | |
Definition at line 382 of file api_serialise.cc.
Enumerator | |
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NONE | |
CLONE |
Definition at line 384 of file api_serialise.cc.
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inline |
Definition at line 388 of file api_serialise.cc.
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inlineoverridevirtual |
Clone this object.
This method allocates and returns a copy of the object it is called on.
If your subclass is called FooWeight and has parameters a and b, then you would implement FooWeight::clone() like so:
FooWeight * FooWeight::clone() const { return new FooWeight(a, b); }
Note that the returned object will be deallocated by Xapian after use with "delete". If you want to handle the deletion in a special way (for example when wrapping the Xapian API for use from another language) then you can define a static operator delete
method in your subclass as shown here: https://trac.xapian.org/ticket/554#comment:1
Implements Xapian::Weight.
Definition at line 394 of file api_serialise.cc.
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inlineoverridevirtual |
Return an upper bound on what get_sumextra() can return for any document.
This information is used by the matcher to perform various optimisations, so strive to make the bound as tight as possible.
Implements Xapian::Weight.
Definition at line 413 of file api_serialise.cc.
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inlineoverridevirtual |
Return an upper bound on what get_sumpart() can return for any document.
This information is used by the matcher to perform various optimisations, so strive to make the bound as tight as possible.
Implements Xapian::Weight.
Definition at line 407 of file api_serialise.cc.
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inlineoverridevirtual |
Calculate the term-independent weight component for a document.
The parameter gives information about the document which may be used in the calculations:
doclen | The document's length (unnormalised). |
uniqterms | The number of unique terms in the document. |
Implements Xapian::Weight.
Definition at line 409 of file api_serialise.cc.
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inlineoverridevirtual |
Calculate the weight contribution for this object's term to a document.
The parameters give information about the document which may be used in the calculations:
wdf | The within document frequency of the term in the document. |
doclen | The document's length (unnormalised). |
uniqterms | Number of unique terms in the document (used for absolute smoothing). |
Implements Xapian::Weight.
Definition at line 402 of file api_serialise.cc.
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inlineoverridevirtual |
Allow the subclass to perform any initialisation it needs to.
factor | Any scaling factor (e.g. from OP_SCALE_WEIGHT). If the Weight object is for the term-independent weight supplied by get_sumextra()/get_maxextra(), then init(0.0) is called (starting from Xapian 1.2.11 and 1.3.1 - earlier versions failed to call init() for such Weight objects). |
Implements Xapian::Weight.
Definition at line 400 of file api_serialise.cc.
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inlineoverridevirtual |
Return the name of this weighting scheme.
This name is used by the remote backend. It is passed along with the serialised parameters to the remote server so that it knows which class to create.
Return the full namespace-qualified name of your class here - if your class is called FooWeight, return "FooWeight" from this method (Xapian::BM25Weight returns "Xapian::BM25Weight" here).
If you don't want to support the remote backend, you can use the default implementation which simply returns an empty string.
Reimplemented from Xapian::Weight.
Definition at line 390 of file api_serialise.cc.
failmode ExceptionalWeight::fail |
Definition at line 386 of file api_serialise.cc.