mayya-sharipova commented on code in PR #14078: URL: https://github.com/apache/lucene/pull/14078#discussion_r1890793535
########## lucene/core/src/java/org/apache/lucene/codecs/lucene102/Lucene102BinaryQuantizedVectorsFormat.java: ########## @@ -0,0 +1,135 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.lucene.codecs.lucene102; + +import java.io.IOException; +import org.apache.lucene.codecs.hnsw.FlatVectorScorerUtil; +import org.apache.lucene.codecs.hnsw.FlatVectorsFormat; +import org.apache.lucene.codecs.hnsw.FlatVectorsReader; +import org.apache.lucene.codecs.hnsw.FlatVectorsWriter; +import org.apache.lucene.codecs.lucene99.Lucene99FlatVectorsFormat; +import org.apache.lucene.index.SegmentReadState; +import org.apache.lucene.index.SegmentWriteState; + +/** + * Copied from Lucene, replace with Lucene's implementation sometime after Lucene 10 Codec for + * encoding/decoding binary quantized vectors The binary quantization format used here is a + * per-vector optimized scalar quantization. Also see {@link + * org.apache.lucene.util.quantization.OptimizedScalarQuantizer}. Some of key features are: + * + * <ul> + * <li>Estimating the distance between two vectors using their centroid normalized distance. This + * requires some additional corrective factors, but allows for centroid normalization to + * occur. + * <li>Optimized scalar quantization to single bit level of centroid normalized vectors. + * <li>Asymmetric quantization of vectors, where query vectors are quantized to half-byte (4 bits) + * precision (normalized to the centroid) and then compared directly against the single bit + * quantized vectors in the index. + * <li>Transforming the half-byte quantized query vectors in such a way that the comparison with + * single bit vectors can be done with bit arithmetic. + * </ul> + * + * The format is stored in two files: + * + * <h2>.veb (vector data) file</h2> + * + * <p>Stores the binary quantized vectors in a flat format. Additionally, it stores each vector's + * corrective factors. At the end of the file, additional information is stored for vector ordinal + * to centroid ordinal mapping and sparse vector information. + * + * <ul> + * <li>For each vector: + * <ul> + * <li><b>[byte]</b> the binary quantized values, each byte holds 8 bits. + * <li><b>[float]</b> the optimized quantiles and an additional similarity dependent + * corrective factor. + * <li><b>short</b> the sum of the quantized components + * </ul> + * <li>After the vectors, sparse vector information keeping track of monotonic blocks. + * </ul> + * + * <h2>.vemb (vector metadata) file</h2> + * + * <p>Stores the metadata for the vectors. This includes the number of vectors, the number of + * dimensions, and file offset information. + * + * <ul> + * <li><b>int</b> the field number + * <li><b>int</b> the vector encoding ordinal + * <li><b>int</b> the vector similarity ordinal + * <li><b>vint</b> the vector dimensions + * <li><b>vlong</b> the offset to the vector data in the .veb file + * <li><b>vlong</b> the length of the vector data in the .veb file + * <li><b>vint</b> the number of vectors + * <li><b>[float]</b> the centroid + * <li><b>float</b> the centroid square magnitude + * <li>The sparse vector information, if required, mapping vector ordinal to doc ID + * </ul> + */ +public class Lucene102BinaryQuantizedVectorsFormat extends FlatVectorsFormat { + + public static final byte QUERY_BITS = 4; + public static final byte INDEX_BITS = 1; + + public static final String BINARIZED_VECTOR_COMPONENT = "BVEC"; + public static final String NAME = "Lucene102BinaryQuantizedVectorsFormat"; + + static final int VERSION_START = 0; + static final int VERSION_CURRENT = VERSION_START; + static final String META_CODEC_NAME = "Lucene102BinaryQuantizedVectorsFormatMeta"; + static final String VECTOR_DATA_CODEC_NAME = "Lucene102BinaryQuantizedVectorsFormatData"; + static final String META_EXTENSION = "vemb"; + static final String VECTOR_DATA_EXTENSION = "veb"; + static final int DIRECT_MONOTONIC_BLOCK_SHIFT = 16; + + private static final FlatVectorsFormat rawVectorFormat = + new Lucene99FlatVectorsFormat(FlatVectorScorerUtil.getLucene99FlatVectorsScorer()); + + private static final Lucene102BinaryFlatVectorsScorer scorer = + new Lucene102BinaryFlatVectorsScorer(FlatVectorScorerUtil.getLucene99FlatVectorsScorer()); + + /** Creates a new instance with the default number of vectors per cluster. */ + public Lucene102BinaryQuantizedVectorsFormat() { + super(NAME); + } + + @Override + public FlatVectorsWriter fieldsWriter(SegmentWriteState state) throws IOException { + return new Lucene102BinaryQuantizedVectorsWriter( + scorer, rawVectorFormat.fieldsWriter(state), state); + } + + @Override + public FlatVectorsReader fieldsReader(SegmentReadState state) throws IOException { + return new Lucene102BinaryQuantizedVectorsReader( + state, rawVectorFormat.fieldsReader(state), scorer); + } + + @Override + public int getMaxDimensions(String fieldName) { + return 1024; + } + + @Override + public String toString() { + return "Lucene102BinaryQuantizedVectorsFormat(name=" + + NAME + + ", flatVectorScorer=" + + scorer Review Comment: nit: should we also add + ", rawVectorFormat=" + rawVectorFormat? -- This is an automated message from the Apache Git Service. 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