## Package org.apache.lucene.queries.function.valuesource

A variety of functions to use with FunctionQuery.

See:
Description

Class Summary
BoolFunction: Abstract parent class for those `ValueSource` implementations which apply boolean logic to their values
ByteFieldSource: Obtains int field values from the `FieldCache` using `getInts()` and makes those values available as other numeric types, casting as needed.
BytesRefFieldSource: An implementation for retrieving `FunctionValues` instances for string based fields.
ConstNumberSource: `ConstNumberSource` is the base class for all constant numbers
ConstValueSource: `ConstValueSource` returns a constant for all documents
DefFunction: `ValueSource` implementation which only returns the values from the provided ValueSources which are available for a particular docId.
DivFloatFunction: Function to divide "a" by "b"
DocFreqValueSource: `DocFreqValueSource` returns the number of documents containing the term.
DoubleConstValueSource: Function that returns a constant double value for every document.
DoubleFieldSource: Obtains float field values from the `FieldCache` using `getFloats()` and makes those values available as other numeric types, casting as needed.
DualFloatFunction: Abstract `ValueSource` implementation which wraps two ValueSources and applies an extendible float function to their values.
FieldCacheSource: A base class for ValueSource implementations that retrieve values for a single field from the `FieldCache`.
FloatFieldSource: Obtains float field values from the `FieldCache` using `getFloats()` and makes those values available as other numeric types, casting as needed.
IDFValueSource: Function that returns `#idf(long, long)` for every document.
IfFunction: Depending on the boolean value of the `ifSource` function, returns the value of the `trueSource` or `falseSource` function.
IntFieldSource: Obtains int field values from the `FieldCache` using `getInts()` and makes those values available as other numeric types, casting as needed.
JoinDocFreqValueSource: Use a field value and find the Document Frequency within another field.
LinearFloatFunction: `LinearFloatFunction` implements a linear function over another `ValueSource`.
LiteralValueSource: Pass a the field value through as a String, no matter the type // Q: doesn't this mean it's a "string"?
LongFieldSource: Obtains float field values from the `FieldCache` using `getFloats()` and makes those values available as other numeric types, casting as needed.
MaxDocValueSource: Returns the value of `IndexReader.maxDoc()` for every document.
MaxFloatFunction: `MaxFloatFunction` returns the max of it's components.
MinFloatFunction: `MinFloatFunction` returns the min of it's components.
MultiBoolFunction: Abstract `ValueSource` implementation which wraps multiple ValueSources and applies an extendible boolean function to their values.
MultiFloatFunction: Abstract `ValueSource` implementation which wraps multiple ValueSources and applies an extendible float function to their values.
MultiFunction: Abstract parent class for `ValueSource` implementations that wrap multiple ValueSources and apply their own logic.
MultiValueSource: A `ValueSource` that abstractly represents `ValueSource`s for poly fields, and other things.
NormValueSource: Function that returns `TFIDFSimilarity.decodeNormValue(byte)` for every document.
NumDocsValueSource: Returns the value of `IndexReader.numDocs()` for every document.
OrdFieldSource: Obtains the ordinal of the field value from the default Lucene `FieldCache` using getStringIndex().
PowFloatFunction: Function to raise the base "a" to the power "b"
ProductFloatFunction: `ProductFloatFunction` returns the product of it's components.
QueryValueSource: `QueryValueSource` returns the relevance score of the query
RangeMapFloatFunction: `LinearFloatFunction` implements a linear function over another `ValueSource`.
ReciprocalFloatFunction: `ReciprocalFloatFunction` implements a reciprocal function f(x) = a/(mx+b), based on the float value of a field or function as exported by `ValueSource`.
ReverseOrdFieldSource: Obtains the ordinal of the field value from the default Lucene `FieldCache` using getTermsIndex() and reverses the order.
ScaleFloatFunction: Scales values to be between min and max.
ShortFieldSource: Obtains short field values from the `FieldCache` using `getShorts()` and makes those values available as other numeric types, casting as needed.
SimpleBoolFunction: `BoolFunction` implementation which applies an extendible boolean function to the values of a single wrapped `ValueSource`.
SimpleFloatFunction: A simple float function with a single argument
SingleFunction: A function with a single argument
SumFloatFunction: `SumFloatFunction` returns the sum of it's components.
SumTotalTermFreqValueSource: `SumTotalTermFreqValueSource` returns the number of tokens.
TermFreqValueSource: Function that returns `DocsEnum.freq()` for the supplied term in every document.
TFValueSource: Function that returns `TFIDFSimilarity.tf(int)` for every document.
TotalTermFreqValueSource: `TotalTermFreqValueSource` returns the total term freq (sum of term freqs across all documents).
VectorValueSource: Converts individual ValueSource instances to leverage the FunctionValues *Val functions that work with multiple values, i.e.

## Package org.apache.lucene.queries.function.valuesource Description

A variety of functions to use with FunctionQuery.

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