xapian-core
1.4.26
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Xapian::Weight subclass which adds laziness. More...
Public Member Functions | |
LazyWeight (LeafPostList *pl_, Xapian::Weight *real_wt_, Xapian::Weight::Internal *stats_, Xapian::termcount qlen_, Xapian::termcount wqf__, double factor_) | |
std::string | name () const override |
Return the name of this weighting scheme. More... | |
std::string | serialise () const override |
Return this object's parameters serialised as a single string. More... | |
LazyWeight * | unserialise (const std::string &serialised) const override |
Unserialise parameters. More... | |
double | get_sumpart (Xapian::termcount wdf, Xapian::termcount doclen, Xapian::termcount uniqterms) 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 doclen, Xapian::termcount uniqterms) 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... | |
Private Member Functions | |
LazyWeight * | clone () const override |
Clone this object. More... | |
void | init (double factor_) override |
Allow the subclass to perform any initialisation it needs to. More... | |
Private Attributes | |
LeafPostList * | pl |
Xapian::Weight * | real_wt |
Xapian::Weight::Internal * | stats |
Xapian::termcount | qlen |
Xapian::termcount | wqf |
double | factor |
Additional Inherited Members | |
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... | |
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... | |
Xapian::Weight subclass which adds laziness.
For terms from a wildcard when remote databases are involved, we need to delay calling init_() on the weight object until the stats for the terms from the wildcard have been collated.
Definition at line 50 of file localsubmatch.cc.
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inline |
Definition at line 68 of file localsubmatch.cc.
References name.
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overrideprivatevirtual |
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 98 of file localsubmatch.cc.
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overridevirtual |
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 159 of file localsubmatch.cc.
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overridevirtual |
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 152 of file localsubmatch.cc.
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overridevirtual |
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 143 of file localsubmatch.cc.
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overridevirtual |
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 132 of file localsubmatch.cc.
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overrideprivatevirtual |
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 104 of file localsubmatch.cc.
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overridevirtual |
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 111 of file localsubmatch.cc.
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overridevirtual |
Return this object's parameters serialised as a single string.
If you don't want to support the remote backend, you can use the default implementation which simply throws Xapian::UnimplementedError.
Reimplemented from Xapian::Weight.
Definition at line 120 of file localsubmatch.cc.
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overridevirtual |
Unserialise parameters.
This method unserialises parameters serialised by the serialise() method and allocates and returns a new object initialised with them.
If you don't want to support the remote backend, you can use the default implementation which simply throws Xapian::UnimplementedError.
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
serialised | A string containing the serialised parameters. |
Reimplemented from Xapian::Weight.
Definition at line 126 of file localsubmatch.cc.
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private |
Definition at line 61 of file localsubmatch.cc.
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private |
Definition at line 51 of file localsubmatch.cc.
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private |
Definition at line 57 of file localsubmatch.cc.
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private |
Definition at line 53 of file localsubmatch.cc.
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private |
Definition at line 55 of file localsubmatch.cc.
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private |
Definition at line 59 of file localsubmatch.cc.