org.elasticsearch.search.aggregations.bucket.terms.heuristic.GND Maven / Gradle / Ivy
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/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.search.aggregations.bucket.terms.heuristic;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.xcontent.ConstructingObjectParser;
import org.elasticsearch.xcontent.XContentBuilder;
import java.io.IOException;
import static org.elasticsearch.xcontent.ConstructingObjectParser.optionalConstructorArg;
public class GND extends NXYSignificanceHeuristic {
public static final String NAME = "gnd";
public static final ConstructingObjectParser PARSER = new ConstructingObjectParser<>(NAME, args -> {
boolean backgroundIsSuperset = args[0] == null ? true : (boolean) args[0];
return new GND(backgroundIsSuperset);
});
static {
PARSER.declareBoolean(optionalConstructorArg(), BACKGROUND_IS_SUPERSET);
}
public GND(boolean backgroundIsSuperset) {
super(true, backgroundIsSuperset);
}
/**
* Read from a stream.
*/
public GND(StreamInput in) throws IOException {
super(true, in.readBoolean());
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeBoolean(backgroundIsSuperset);
}
@Override
public boolean equals(Object other) {
if ((other instanceof GND) == false) {
return false;
}
return super.equals(other);
}
@Override
public int hashCode() {
int result = NAME.hashCode();
result = 31 * result + super.hashCode();
return result;
}
/**
* Calculates Google Normalized Distance, as described in "The Google Similarity Distance", Cilibrasi and Vitanyi, 2007
* link: http://arxiv.org/pdf/cs/0412098v3.pdf
*/
@Override
public double getScore(long subsetFreq, long subsetSize, long supersetFreq, long supersetSize) {
Frequencies frequencies = computeNxys(subsetFreq, subsetSize, supersetFreq, supersetSize, "GND");
double fx = frequencies.N1_;
double fy = frequencies.N_1;
double fxy = frequencies.N11;
double N = frequencies.N;
if (fxy == 0) {
// no co-occurrence
return 0.0;
}
if ((fx == fy) && (fx == fxy)) {
// perfect co-occurrence
return 1.0;
}
double score = (Math.max(Math.log(fx), Math.log(fy)) - Math.log(fxy)) / (Math.log(N) - Math.min(Math.log(fx), Math.log(fy)));
// we must invert the order of terms because GND scores relevant terms low
score = Math.exp(-1.0d * score);
return score;
}
@Override
public String getWriteableName() {
return NAME;
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject(NAME);
builder.field(BACKGROUND_IS_SUPERSET.getPreferredName(), backgroundIsSuperset);
builder.endObject();
return builder;
}
public static class GNDBuilder extends NXYBuilder {
public GNDBuilder(boolean backgroundIsSuperset) {
super(true, backgroundIsSuperset);
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject(NAME);
builder.field(BACKGROUND_IS_SUPERSET.getPreferredName(), backgroundIsSuperset);
builder.endObject();
return builder;
}
}
}