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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.searchlib.ranking.features;
import com.yahoo.api.annotations.Beta;
import com.yahoo.searchlib.rankingexpression.evaluation.DoubleValue;
import com.yahoo.searchlib.rankingexpression.evaluation.Value;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
/**
* Calculates the elementCompleteness features
*
* @author bratseth
*/
public class ElementCompleteness {
/** Hardcoded to default for now */
private static final double fieldCompletenessImportance = 0.05;
/**
* Computes the following elementCompleteness features:
* <ul>
* <li><code>completeness</code>
* <li><code>fieldCompleteness</code>
* <li><code>queryCompleteness</code>
* <li><code>elementWeight</code>
* </ul>
*
* @param queryTerms the query terms with associated weights to compute over
* @param field a set of weighted field values, where each is taken to be a space-separated string of tokens
* @return a features object containing the values listed above
*/
public static Features compute(Map<String, Integer> queryTerms, Item[] field) {
double completeness = 0;
double fieldCompleteness = 0;
double queryCompleteness = 0;
double elementWeight = 0;
double queryTermWeightSum = sum(queryTerms.values());
for (Item item : field) {
String[] itemTokens =item.value().split(" ");
int matchCount = 0;
int matchWeightSum = 0;
for (String token : itemTokens) {
Integer weight = queryTerms.get(token);
if (weight == null) continue;
matchCount++;
matchWeightSum += weight;
}
double itemFieldCompleteness = (double)matchCount / itemTokens.length;
double itemQueryCompleteness = matchWeightSum / queryTermWeightSum;
double itemCompleteness =
fieldCompletenessImportance * itemFieldCompleteness +
(1 - fieldCompletenessImportance) * itemQueryCompleteness;
if (itemCompleteness > completeness) {
completeness = itemCompleteness;
fieldCompleteness = itemFieldCompleteness;
queryCompleteness = itemQueryCompleteness;
elementWeight = item.weight();
}
}
Map<String, Value> features = new HashMap<>();
features.put("completeness", new DoubleValue(completeness));
features.put("fieldCompleteness", new DoubleValue(fieldCompleteness));
features.put("queryCompleteness", new DoubleValue(queryCompleteness));
features.put("elementWeight", new DoubleValue(elementWeight));
return new Features(features);
}
private static int sum(Collection<Integer> integers) {
int sum = 0;
for (int integer : integers)
sum += integer;
return sum;
}
public static class Item {
private final String value;
private final double weight;
public Item(String value, double weight) {
this.value = value;
this.weight = weight;
}
public String value() { return value; }
public double weight() { return weight; }
}
}
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