eliaporciani commented on code in PR #12253: URL: https://github.com/apache/lucene/pull/12253#discussion_r1226655236
########## lucene/queries/src/java/org/apache/lucene/queries/function/valuesource/KnnVectorFieldSource.java: ########## @@ -0,0 +1,112 @@ +/* + * 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.queries.function.valuesource; + +import java.io.IOException; +import java.util.Map; +import org.apache.lucene.index.ByteVectorValues; +import org.apache.lucene.index.FloatVectorValues; +import org.apache.lucene.index.LeafReaderContext; +import org.apache.lucene.queries.function.FunctionValues; +import org.apache.lucene.queries.function.ValueSource; +import org.apache.lucene.search.DocIdSetIterator; + +/** An implementation for retrieving {@link FunctionValues} instances for knn vectors fields. */ +public class KnnVectorFieldSource extends ValueSource { + private final String fieldName; + + public KnnVectorFieldSource(String fieldName) { + this.fieldName = fieldName; + } + + @Override + public FunctionValues getValues(Map<Object, Object> context, LeafReaderContext readerContext) + throws IOException { + + final FloatVectorValues floatValues = readerContext.reader().getFloatVectorValues(fieldName); + final ByteVectorValues byteValues = readerContext.reader().getByteVectorValues(fieldName); + + if (floatValues == null && byteValues == null) { + throw new IllegalArgumentException( + "no vector value is indexed for field '" + fieldName + "'"); + } + return new FunctionValues() { + int lastDocID; + + @Override + public float[] floatVectorVal(int doc) throws IOException { + float[] floatVector = null; + if (floatValues != null && exists(floatValues, doc)) { + floatVector = floatValues.vectorValue(); + } else { + byte[] byteVector = byteVectorVal(doc); + if (byteVector != null) { + floatVector = new float[byteVector.length]; + for (int i = 0; i < byteVector.length; i++) { + floatVector[i] = byteVector[i]; + } + } + } + return floatVector; + } Review Comment: Initially, we had separate implementations for byte and float vectors. The change in approach can be seen in the commit [cb4b77c9f72551cb014d155586e399365fbcba5d](https://github.com/apache/lucene/pull/12253/commits/cb4b77c9f72551cb014d155586e399365fbcba5d). We made the decision to explore the possibility of abstracting over the vector encoding to create a simpler API for the caller. There were two main reasons for pursuing this change: - Code duplication: Having separate implementations resulted in duplicate code for byte and float vectors. - Difficulty in using float[] and byte[] vectors interchangeably: The knn vectors, whether byte or float, essentially represented the same field. The difference lay in the underlying encoding and the precision used to store the vectors. The decision to use the byte vector format over the float vector format was primarily driven by non-functional aspects such as space occupancy and performance. The proposed approach strikes a good balance in terms of abstraction level for both types of vectors. If there are compelling reasons for not proceeding with this approach, we could consider reverting to the point where the two implementations were separate. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
