Package org.apache.lucene.codecs.lucene99

Class Lucene99FlatVectorsFormat

  • public final class Lucene99FlatVectorsFormat
extends FlatVectorsFormat
    Lucene 9.9 flat vector format, which encodes numeric vector values

    .vec (vector data) file

    For each field:

    • Vector data ordered by field, document ordinal, and vector dimension. When the vectorEncoding is BYTE, each sample is stored as a single byte. When it is FLOAT32, each sample is stored as an IEEE float in little-endian byte order.
    • DocIds encoded by IndexedDISI.writeBitSet(DocIdSetIterator, IndexOutput, byte), note that only in sparse case
    • OrdToDoc was encoded by DirectMonotonicWriter, note that only in sparse case

    .vemf (vector metadata) file

    For each field:

    • [int32] field number
    • [int32] vector similarity function ordinal
    • [vlong] offset to this field's vectors in the .vec file
    • [vlong] length of this field's vectors, in bytes
    • [vint] dimension of this field's vectors
    • [int] the number of documents having values for this field
    • [int8] if equals to -1, dense – all documents have values for a field. If equals to 0, sparse – some documents missing values.
    • DocIds were encoded by IndexedDISI.writeBitSet(DocIdSetIterator, IndexOutput, byte)
    • OrdToDoc was encoded by DirectMonotonicWriter, note that only in sparse case
    WARNING: This API is experimental and might change in incompatible ways in the next release.