dungba88 commented on code in PR #13991: URL: https://github.com/apache/lucene/pull/13991#discussion_r1841484667
########## lucene/core/src/java/org/apache/lucene/index/MultiVectorSimilarityFunction.java: ########## @@ -0,0 +1,202 @@ +/* + * 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.index; + +import java.util.ArrayList; +import java.util.List; +import org.apache.lucene.util.ArrayUtil; + +/** + * Computes similarity between two multi-vectors. + * + * <p>A multi-vector is a collection of multiple vectors that represent a single document or query. + * MultiVectorSimilarityFunction is used to determine nearest neighbors during indexing and search + * on multi-vectors. + */ +public class MultiVectorSimilarityFunction { + + /** Aggregation function to combine similarity across multiple vector values */ + public enum Aggregation { + + /** + * Sum_Max Similarity between two multi-vectors. Computes the sum of maximum similarity found + * for each vector in the first multi-vector against all vectors in the second multi-vector. + */ + SUM_MAX { + @Override + public float aggregate( + float[] outer, + float[] inner, + VectorSimilarityFunction vectorSimilarityFunction, + int dimension) { + if (outer.length % dimension != 0 || inner.length % dimension != 0) { + throw new IllegalArgumentException("Multi vectors do not match provided dimension value"); + } + + // TODO: can we avoid making vector copies? + List<float[]> outerList = new ArrayList<>(); + List<float[]> innerList = new ArrayList<>(); + for (int i = 0; i < outer.length; i += dimension) { + outerList.add(ArrayUtil.copyOfSubArray(outer, i, i + dimension)); + } + for (int i = 0; i < inner.length; i += dimension) { + innerList.add(ArrayUtil.copyOfSubArray(inner, i, i + dimension)); + } + + float result = 0f; + for (float[] o : outerList) { + float maxSim = Float.MIN_VALUE; + for (float[] i : innerList) { + maxSim = Float.max(maxSim, vectorSimilarityFunction.compare(o, i)); Review Comment: If we add another `compare` method with start and end indexes for both inner and outer, I guess we won't need to copy the array? ########## lucene/core/src/java/org/apache/lucene/index/MultiVectorSimilarityFunction.java: ########## @@ -0,0 +1,202 @@ +/* + * 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.index; + +import java.util.ArrayList; +import java.util.List; +import org.apache.lucene.util.ArrayUtil; + +/** + * Computes similarity between two multi-vectors. + * + * <p>A multi-vector is a collection of multiple vectors that represent a single document or query. + * MultiVectorSimilarityFunction is used to determine nearest neighbors during indexing and search + * on multi-vectors. + */ +public class MultiVectorSimilarityFunction { + + /** Aggregation function to combine similarity across multiple vector values */ + public enum Aggregation { + + /** + * Sum_Max Similarity between two multi-vectors. Computes the sum of maximum similarity found + * for each vector in the first multi-vector against all vectors in the second multi-vector. + */ + SUM_MAX { + @Override + public float aggregate( + float[] outer, + float[] inner, + VectorSimilarityFunction vectorSimilarityFunction, + int dimension) { + if (outer.length % dimension != 0 || inner.length % dimension != 0) { + throw new IllegalArgumentException("Multi vectors do not match provided dimension value"); + } + + // TODO: can we avoid making vector copies? + List<float[]> outerList = new ArrayList<>(); + List<float[]> innerList = new ArrayList<>(); + for (int i = 0; i < outer.length; i += dimension) { + outerList.add(ArrayUtil.copyOfSubArray(outer, i, i + dimension)); + } + for (int i = 0; i < inner.length; i += dimension) { + innerList.add(ArrayUtil.copyOfSubArray(inner, i, i + dimension)); + } + + float result = 0f; + for (float[] o : outerList) { + float maxSim = Float.MIN_VALUE; + for (float[] i : innerList) { + maxSim = Float.max(maxSim, vectorSimilarityFunction.compare(o, i)); + } + result += maxSim; + } + return result; + } + + @Override + public float aggregate( Review Comment: It's so unfortunate that Java doesn't support generic primitive array and has to have duplicate code. -- This is an automated message from the Apache Git Service. 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