ercsonusharma commented on code in PR #3418: URL: https://github.com/apache/solr/pull/3418#discussion_r2203163245
########## solr/core/src/java/org/apache/solr/search/combine/ReciprocalRankFusion.java: ########## @@ -0,0 +1,234 @@ +/* + * 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.solr.search.combine; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.StringJoiner; +import org.apache.lucene.document.Document; +import org.apache.lucene.search.Explanation; +import org.apache.lucene.search.Query; +import org.apache.lucene.search.TotalHits; +import org.apache.solr.common.params.CombinerParams; +import org.apache.solr.common.params.SolrParams; +import org.apache.solr.common.util.NamedList; +import org.apache.solr.common.util.SimpleOrderedMap; +import org.apache.solr.handler.component.ShardDoc; +import org.apache.solr.schema.IndexSchema; +import org.apache.solr.search.DocIterator; +import org.apache.solr.search.DocList; +import org.apache.solr.search.DocSlice; +import org.apache.solr.search.QueryResult; +import org.apache.solr.search.SolrIndexSearcher; +import org.apache.solr.search.SortedIntDocSet; + +/** + * The ReciprocalRankFusion class implements a query and response combiner that uses the Reciprocal + * Rank Fusion (RRF) algorithm to combine multiple ranked lists into a single ranked list. + */ +public class ReciprocalRankFusion extends QueryAndResponseCombiner { + + private final int k; + + /** + * Constructs a ReciprocalRankFusion instance. + * + * @param requestParams the SolrParams containing the configuration parameters for this combiner. + */ + public ReciprocalRankFusion(SolrParams requestParams) { + super(requestParams); + this.k = + requestParams.getInt(CombinerParams.COMBINER_RRF_K, CombinerParams.COMBINER_RRF_K_DEFAULT); + } + + @Override + public QueryResult combine(List<QueryResult> rankedLists) { + List<DocList> docLists = new ArrayList<>(rankedLists.size()); + for (QueryResult rankedList : rankedLists) { + docLists.add(rankedList.getDocList()); + } + QueryResult combinedResult = new QueryResult(); + combineResults(combinedResult, docLists, false); + return combinedResult; + } + + @Override + public List<ShardDoc> combine(Map<String, List<ShardDoc>> shardDocMap) { + HashMap<String, Float> docIdToScore = new HashMap<>(); + Map<String, ShardDoc> docIdToShardDoc = new HashMap<>(); + List<ShardDoc> finalShardDocList = new ArrayList<>(); + for (Map.Entry<String, List<ShardDoc>> shardDocEntry : shardDocMap.entrySet()) { + List<ShardDoc> shardDocList = shardDocEntry.getValue(); + int ranking = 1; + while (ranking <= shardDocList.size() && ranking <= upTo) { + String docId = shardDocList.get(ranking - 1).id.toString(); + docIdToShardDoc.put(docId, shardDocList.get(ranking - 1)); + float rrfScore = 1f / (k + ranking); + docIdToScore.compute(docId, (id, score) -> (score == null) ? rrfScore : score + rrfScore); + ranking++; + } + } + // TODO: Add the remaining items out of upTo limit to the docIdToScore + List<Map.Entry<String, Float>> sortedByScoreDescending = + docIdToScore.entrySet().stream() + .sorted(Collections.reverseOrder(Map.Entry.comparingByValue())) + .toList(); + for (Map.Entry<String, Float> scoredDoc : sortedByScoreDescending) { + String docId = scoredDoc.getKey(); + Float score = scoredDoc.getValue(); + ShardDoc shardDoc = docIdToShardDoc.get(docId); + shardDoc.score = score; Review Comment: ShardDoc is local to the mergeIds method and not shared in any other object available to other component. Also, `SolrDocumentList` is created later using ShardDoc. Please help me understand if it's being shared anywhere else. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
