| /* |
| * 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.client.solrj.io.eval; |
| |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.Locale; |
| |
| import org.apache.commons.math3.util.Precision; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpression; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamFactory; |
| |
| public class CosineSimilarityEvaluator extends RecursiveNumericEvaluator implements TwoValueWorker { |
| protected static final long serialVersionUID = 1L; |
| |
| public CosineSimilarityEvaluator(StreamExpression expression, StreamFactory factory) throws IOException{ |
| super(expression, factory); |
| } |
| |
| @Override |
| public Object doWork(Object first, Object second) throws IOException{ |
| if(null == first){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the first value",toExpression(constructingFactory))); |
| } |
| if(null == second){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - null found for the second value",toExpression(constructingFactory))); |
| } |
| if(!(first instanceof List<?>)){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the first value, expecting a list of numbers",toExpression(constructingFactory), first.getClass().getSimpleName())); |
| } |
| if(!(second instanceof List<?>)){ |
| throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - found type %s for the second value, expecting a list of numbers",toExpression(constructingFactory), first.getClass().getSimpleName())); |
| } |
| |
| @SuppressWarnings({"unchecked"}) |
| double[] d1 = ((List) first).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray(); |
| @SuppressWarnings({"unchecked"}) |
| double[] d2 = ((List) second).stream().mapToDouble(value -> ((Number) value).doubleValue()).toArray(); |
| |
| return cosineSimilarity(d1, d2); |
| } |
| |
| public static double cosineSimilarity(double[] vectorA, double[] vectorB) { |
| double dotProduct = 0.0; |
| double normA = 0.0; |
| double normB = 0.0; |
| for (int i = 0; i < vectorA.length; i++) { |
| dotProduct += vectorA[i] * vectorB[i]; |
| normA += Math.pow(vectorA[i], 2); |
| normB += Math.pow(vectorB[i], 2); |
| } |
| double d = dotProduct / (Math.sqrt(normA) * Math.sqrt(normB)); |
| return Precision.round(d, 8); |
| } |
| |
| } |