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| 1 | +/* |
| 2 | + * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one |
| 3 | + * or more contributor license agreements. Licensed under the Elastic License |
| 4 | + * 2.0; you may not use this file except in compliance with the Elastic License |
| 5 | + * 2.0. |
| 6 | + */ |
| 7 | + |
| 8 | +package org.elasticsearch.compute.operator; |
| 9 | + |
| 10 | +import org.apache.lucene.util.BytesRef; |
| 11 | +import org.elasticsearch.compute.data.Block; |
| 12 | +import org.elasticsearch.compute.data.BytesRefBlock; |
| 13 | +import org.elasticsearch.compute.data.DoubleVector; |
| 14 | +import org.elasticsearch.compute.data.DoubleVectorBlock; |
| 15 | +import org.elasticsearch.compute.data.Page; |
| 16 | + |
| 17 | +import java.util.ArrayDeque; |
| 18 | +import java.util.Collection; |
| 19 | +import java.util.Deque; |
| 20 | +import java.util.HashMap; |
| 21 | +import java.util.Map; |
| 22 | + |
| 23 | +public class LinearScoreEvalOperator implements Operator { |
| 24 | + public record Factory(int scorePosition, int discriminatorPosition, Map<String, Double> weights, String normalizer) |
| 25 | + implements |
| 26 | + OperatorFactory { |
| 27 | + |
| 28 | + @Override |
| 29 | + public Operator get(DriverContext driverContext) { |
| 30 | + return new LinearScoreEvalOperator(scorePosition, discriminatorPosition, weights, normalizer); |
| 31 | + } |
| 32 | + |
| 33 | + @Override |
| 34 | + public String describe() { |
| 35 | + return "LinearScoreEvalOperator"; |
| 36 | + } |
| 37 | + } |
| 38 | + |
| 39 | + private final int scorePosition; |
| 40 | + private final int discriminatorPosition; |
| 41 | + private final Map<String, Double> weights; |
| 42 | + private final Normalizer normalizer; |
| 43 | + |
| 44 | + private final Deque<Page> inputPages; |
| 45 | + private final Deque<Page> outputPages; |
| 46 | + private boolean finished; |
| 47 | + |
| 48 | + public LinearScoreEvalOperator(int scorePosition, int discriminatorPosition, Map<String, Double> weights, String normalizerType) { |
| 49 | + this.scorePosition = scorePosition; |
| 50 | + this.discriminatorPosition = discriminatorPosition; |
| 51 | + this.weights = weights; |
| 52 | + this.normalizer = createNormalizer(normalizerType); |
| 53 | + |
| 54 | + finished = false; |
| 55 | + inputPages = new ArrayDeque<>(); |
| 56 | + outputPages = new ArrayDeque<>(); |
| 57 | + } |
| 58 | + |
| 59 | + @Override |
| 60 | + public boolean needsInput() { |
| 61 | + return finished == false; |
| 62 | + } |
| 63 | + |
| 64 | + @Override |
| 65 | + public void addInput(Page page) { |
| 66 | + inputPages.add(page); |
| 67 | + } |
| 68 | + |
| 69 | + @Override |
| 70 | + public void finish() { |
| 71 | + if (finished == false) { |
| 72 | + finished = true; |
| 73 | + createOutputPages(); |
| 74 | + } |
| 75 | + } |
| 76 | + |
| 77 | + private void createOutputPages() { |
| 78 | + normalizer.preprocess(inputPages, scorePosition, discriminatorPosition); |
| 79 | + |
| 80 | + while (inputPages.isEmpty() == false) { |
| 81 | + Page inputPage = inputPages.peek(); |
| 82 | + |
| 83 | + BytesRefBlock discriminatorBlock = inputPage.getBlock(discriminatorPosition); |
| 84 | + DoubleVectorBlock initialScoreBlock = inputPage.getBlock(scorePosition); |
| 85 | + |
| 86 | + DoubleVector.Builder scores = discriminatorBlock.blockFactory().newDoubleVectorBuilder(discriminatorBlock.getPositionCount()); |
| 87 | + |
| 88 | + for (int i = 0; i < inputPage.getPositionCount(); i++) { |
| 89 | + String discriminator = discriminatorBlock.getBytesRef(i, new BytesRef()).utf8ToString(); |
| 90 | + |
| 91 | + var weight = weights.get(discriminator) == null ? 1.0 : weights.get(discriminator); |
| 92 | + |
| 93 | + Double score = initialScoreBlock.getDouble(i); |
| 94 | + scores.appendDouble(weight * normalizer.normalize(score, discriminator)); |
| 95 | + } |
| 96 | + Block scoreBlock = scores.build().asBlock(); |
| 97 | + inputPage = inputPage.appendBlock(scoreBlock); |
| 98 | + |
| 99 | + int[] projections = new int[inputPage.getBlockCount() - 1]; |
| 100 | + |
| 101 | + for (int i = 0; i < inputPage.getBlockCount() - 1; i++) { |
| 102 | + projections[i] = i == scorePosition ? inputPage.getBlockCount() - 1 : i; |
| 103 | + } |
| 104 | + inputPages.removeFirst(); |
| 105 | + outputPages.add(inputPage.projectBlocks(projections)); |
| 106 | + inputPage.releaseBlocks(); |
| 107 | + } |
| 108 | + } |
| 109 | + |
| 110 | + @Override |
| 111 | + public boolean isFinished() { |
| 112 | + return finished && outputPages.isEmpty(); |
| 113 | + } |
| 114 | + |
| 115 | + @Override |
| 116 | + public Page getOutput() { |
| 117 | + if (finished == false || outputPages.isEmpty()) { |
| 118 | + return null; |
| 119 | + } |
| 120 | + return outputPages.removeFirst(); |
| 121 | + } |
| 122 | + |
| 123 | + @Override |
| 124 | + public void close() { |
| 125 | + for (Page page : inputPages) { |
| 126 | + page.releaseBlocks(); |
| 127 | + } |
| 128 | + for (Page page : outputPages) { |
| 129 | + page.releaseBlocks(); |
| 130 | + } |
| 131 | + } |
| 132 | + |
| 133 | + @Override |
| 134 | + public String toString() { |
| 135 | + return "LinearScoreEvalOperator[" + scorePosition + ", " + discriminatorPosition + "]"; |
| 136 | + } |
| 137 | + |
| 138 | + private Normalizer createNormalizer(String normalizer) { |
| 139 | + return switch (normalizer.toLowerCase()) { |
| 140 | + case "minmax" -> new MinMaxNormalizer(); |
| 141 | + case "l2_norm" -> new L2NormNormalizer(); |
| 142 | + case "none" -> new NoneNormalizer(); |
| 143 | + case null -> new NoneNormalizer(); |
| 144 | + default -> throw new IllegalArgumentException("Unknown normalizer: " + normalizer); |
| 145 | + }; |
| 146 | + } |
| 147 | + |
| 148 | + private abstract class Normalizer { |
| 149 | + public abstract double normalize(double score, String discriminator); |
| 150 | + |
| 151 | + public abstract void preprocess(Collection<Page> inputPages, int scorePosition, int discriminatorPosition); |
| 152 | + } |
| 153 | + |
| 154 | + private class NoneNormalizer extends Normalizer { |
| 155 | + @Override |
| 156 | + public double normalize(double score, String discriminator) { |
| 157 | + return score; |
| 158 | + } |
| 159 | + |
| 160 | + @Override |
| 161 | + public void preprocess(Collection<Page> inputPages, int scorePosition, int discriminatorPosition) {} |
| 162 | + } |
| 163 | + |
| 164 | + private class L2NormNormalizer extends Normalizer { |
| 165 | + private Map<String, Double> l2Norms = new HashMap<>(); |
| 166 | + |
| 167 | + @Override |
| 168 | + public double normalize(double score, String discriminator) { |
| 169 | + var l2Norm = l2Norms.get(discriminator); |
| 170 | + assert l2Norm != null; |
| 171 | + return l2Norms.get(discriminator) == 0.0 ? 0.0 : score / l2Norm; |
| 172 | + } |
| 173 | + |
| 174 | + @Override |
| 175 | + public void preprocess(Collection<Page> inputPages, int scorePosition, int discriminatorPosition) { |
| 176 | + for (Page inputPage : inputPages) { |
| 177 | + DoubleVectorBlock scoreBlock = inputPage.getBlock(scorePosition); |
| 178 | + BytesRefBlock discriminatorBlock = inputPage.getBlock(discriminatorPosition); |
| 179 | + |
| 180 | + for (int i = 0; i < inputPage.getPositionCount(); i++) { |
| 181 | + double score = scoreBlock.getDouble(i); |
| 182 | + String discriminator = discriminatorBlock.getBytesRef(i, new BytesRef()).utf8ToString(); |
| 183 | + |
| 184 | + l2Norms.compute(discriminator, (k, v) -> v == null ? score * score : v + score * score); |
| 185 | + } |
| 186 | + } |
| 187 | + |
| 188 | + l2Norms.replaceAll((k, v) -> Math.sqrt(v)); |
| 189 | + } |
| 190 | + } |
| 191 | + |
| 192 | + private class MinMaxNormalizer extends Normalizer { |
| 193 | + private Map<String, Double> minScores = new HashMap<>(); |
| 194 | + private Map<String, Double> maxScores = new HashMap<>(); |
| 195 | + |
| 196 | + @Override |
| 197 | + public double normalize(double score, String discriminator) { |
| 198 | + var min = minScores.get(discriminator); |
| 199 | + var max = maxScores.get(discriminator); |
| 200 | + |
| 201 | + assert min != null; |
| 202 | + assert max != null; |
| 203 | + |
| 204 | + if (min.equals(max)) { |
| 205 | + return 0.0; |
| 206 | + } |
| 207 | + |
| 208 | + return (score - min) / (max - min); |
| 209 | + } |
| 210 | + |
| 211 | + @Override |
| 212 | + public void preprocess(Collection<Page> inputPages, int scorePosition, int discriminatorPosition) { |
| 213 | + for (Page inputPage : inputPages) { |
| 214 | + DoubleVectorBlock scoreBlock = inputPage.getBlock(scorePosition); |
| 215 | + BytesRefBlock discriminatorBlock = inputPage.getBlock(discriminatorPosition); |
| 216 | + |
| 217 | + for (int i = 0; i < inputPage.getPositionCount(); i++) { |
| 218 | + double score = scoreBlock.getDouble(i); |
| 219 | + String discriminator = discriminatorBlock.getBytesRef(i, new BytesRef()).utf8ToString(); |
| 220 | + |
| 221 | + minScores.compute(discriminator, (key, value) -> value == null ? score : Math.min(value, score)); |
| 222 | + maxScores.compute(discriminator, (key, value) -> value == null ? score : Math.max(value, score)); |
| 223 | + } |
| 224 | + } |
| 225 | + } |
| 226 | + } |
| 227 | +} |
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