Package org.apache.lucene.codecs.lucene99

# Class Lucene99ScalarQuantizedVectorsFormat

java.lang.Object
org.apache.lucene.codecs.KnnVectorsFormat
org.apache.lucene.codecs.hnsw.FlatVectorsFormat
org.apache.lucene.codecs.lucene99.Lucene99ScalarQuantizedVectorsFormat

All Implemented Interfaces:
  `NamedSPILoader.NamedSPI`

public class Lucene99ScalarQuantizedVectorsFormat extends FlatVectorsFormat
Format supporting vector quantization, storage, and retrieval

WARNING: This API is experimental and might change in incompatible ways in the next release.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final float`
  `DYNAMIC_CONFIDENCE_INTERVAL`
  Dynamic confidence interval
  `static final String`
  `NAME`
  `static final String`
  `QUANTIZED_VECTOR_COMPONENT`

  ### Fields inherited from class org.apache.lucene.codecs.KnnVectorsFormat

  `DEFAULT_MAX_DIMENSIONS, EMPTY`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Lucene99ScalarQuantizedVectorsFormat()`
  Constructs a format using default graph construction parameters
  `Lucene99ScalarQuantizedVectorsFormat(Float confidenceInterval, int bits, boolean compress)`
  Constructs a format using the given graph construction parameters.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static float`
  `calculateDefaultConfidenceInterval(int vectorDimension)`
  `FlatVectorsReader`
  `fieldsReader(SegmentReadState state)`
  Returns a `KnnVectorsReader` to read the vectors from the index.
  `FlatVectorsWriter`
  `fieldsWriter(SegmentWriteState state)`
  Returns a `FlatVectorsWriter` to write the vectors to the index.
  `String`
  `toString()`

  ### Methods inherited from class org.apache.lucene.codecs.hnsw.FlatVectorsFormat

  `getMaxDimensions`

  ### Methods inherited from class org.apache.lucene.codecs.KnnVectorsFormat

  `availableKnnVectorsFormats, forName, getName, reloadKnnVectorsFormat`

  ### Methods inherited from class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- ## Field Details

  - ### QUANTIZED_VECTOR_COMPONENT

    public static final String QUANTIZED_VECTOR_COMPONENT
    See Also:
      - Constant Field Values

  - ### NAME

    public static final String NAME
    See Also:
      - Constant Field Values

  - ### DYNAMIC_CONFIDENCE_INTERVAL

    public static final float DYNAMIC_CONFIDENCE_INTERVAL
    Dynamic confidence interval
    See Also:
      - Constant Field Values

- ## Constructor Details

  - ### Lucene99ScalarQuantizedVectorsFormat

    public Lucene99ScalarQuantizedVectorsFormat()
    Constructs a format using default graph construction parameters

  - ### Lucene99ScalarQuantizedVectorsFormat

    public Lucene99ScalarQuantizedVectorsFormat(Float confidenceInterval, int bits, boolean compress)
    Constructs a format using the given graph construction parameters.
    Parameters:
      `confidenceInterval` - the confidenceInterval for scalar quantizing the vectors, when `null` it is calculated based on the vector dimension. When `0`, the quantiles are dynamically determined by sampling many confidence intervals and determining the most accurate pair.
      `bits` - the number of bits to use for scalar quantization (must be between 1 and 8, inclusive)
      `compress` - whether to compress the quantized vectors by another 50% when bits=4. If `true`, pairs of (4 bit quantized) dimensions are packed into a single byte. This must be `false` when bits=7. This provides a trade-off of 50% reduction in hot vector memory usage during searching, at some decode speed penalty.

- ## Method Details

  - ### calculateDefaultConfidenceInterval

    public static float calculateDefaultConfidenceInterval(int vectorDimension)

  - ### toString

    public String toString()
    Overrides:
      `toString` in class `Object`

  - ### fieldsWriter

    public FlatVectorsWriter fieldsWriter(SegmentWriteState state) throws IOException
    Description copied from class: `FlatVectorsFormat`
    Returns a `FlatVectorsWriter` to write the vectors to the index.
    Specified by:
      `fieldsWriter` in class `FlatVectorsFormat`
    Throws:
      `IOException`

  - ### fieldsReader

    public FlatVectorsReader fieldsReader(SegmentReadState state) throws IOException
    Description copied from class: `FlatVectorsFormat`
    Returns a `KnnVectorsReader` to read the vectors from the index.
    Specified by:
      `fieldsReader` in class `FlatVectorsFormat`
    Throws:
      `IOException`