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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.lucene.search.function;
import org.apache.lucene.search.Explanation;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Writeable;
import java.io.IOException;
import java.util.Locale;
public enum CombineFunction implements Writeable {
MULTIPLY {
@Override
public float combine(double queryScore, double funcScore, double maxBoost) {
return toFloat(queryScore * Math.min(funcScore, maxBoost));
}
@Override
public Explanation explain(Explanation queryExpl, Explanation funcExpl, float maxBoost) {
Explanation boostExpl = Explanation.match(maxBoost, "maxBoost");
Explanation minExpl = Explanation.match(
Math.min(funcExpl.getValue(), maxBoost),
"min of:",
funcExpl, boostExpl);
return Explanation.match(queryExpl.getValue() * minExpl.getValue(),
"function score, product of:", queryExpl, minExpl);
}
},
REPLACE {
@Override
public float combine(double queryScore, double funcScore, double maxBoost) {
return toFloat(Math.min(funcScore, maxBoost));
}
@Override
public Explanation explain(Explanation queryExpl, Explanation funcExpl, float maxBoost) {
Explanation boostExpl = Explanation.match(maxBoost, "maxBoost");
return Explanation.match(
Math.min(funcExpl.getValue(), maxBoost),
"min of:",
funcExpl, boostExpl);
}
},
SUM {
@Override
public float combine(double queryScore, double funcScore, double maxBoost) {
return toFloat(queryScore + Math.min(funcScore, maxBoost));
}
@Override
public Explanation explain(Explanation queryExpl, Explanation funcExpl, float maxBoost) {
Explanation minExpl = Explanation.match(Math.min(funcExpl.getValue(), maxBoost), "min of:",
funcExpl, Explanation.match(maxBoost, "maxBoost"));
return Explanation.match(Math.min(funcExpl.getValue(), maxBoost) + queryExpl.getValue(), "sum of",
queryExpl, minExpl);
}
},
AVG {
@Override
public float combine(double queryScore, double funcScore, double maxBoost) {
return toFloat((Math.min(funcScore, maxBoost) + queryScore) / 2.0);
}
@Override
public Explanation explain(Explanation queryExpl, Explanation funcExpl, float maxBoost) {
Explanation minExpl = Explanation.match(Math.min(funcExpl.getValue(), maxBoost), "min of:",
funcExpl, Explanation.match(maxBoost, "maxBoost"));
return Explanation.match(
toFloat((Math.min(funcExpl.getValue(), maxBoost) + queryExpl.getValue()) / 2.0), "avg of",
queryExpl, minExpl);
}
},
MIN {
@Override
public float combine(double queryScore, double funcScore, double maxBoost) {
return toFloat(Math.min(queryScore, Math.min(funcScore, maxBoost)));
}
@Override
public Explanation explain(Explanation queryExpl, Explanation funcExpl, float maxBoost) {
Explanation innerMinExpl = Explanation.match(
Math.min(funcExpl.getValue(), maxBoost), "min of:",
funcExpl, Explanation.match(maxBoost, "maxBoost"));
return Explanation.match(
Math.min(Math.min(funcExpl.getValue(), maxBoost), queryExpl.getValue()), "min of",
queryExpl, innerMinExpl);
}
},
MAX {
@Override
public float combine(double queryScore, double funcScore, double maxBoost) {
return toFloat(Math.max(queryScore, Math.min(funcScore, maxBoost)));
}
@Override
public Explanation explain(Explanation queryExpl, Explanation funcExpl, float maxBoost) {
Explanation innerMinExpl = Explanation.match(
Math.min(funcExpl.getValue(), maxBoost), "min of:",
funcExpl, Explanation.match(maxBoost, "maxBoost"));
return Explanation.match(
Math.max(Math.min(funcExpl.getValue(), maxBoost), queryExpl.getValue()), "max of:",
queryExpl, innerMinExpl);
}
};
public abstract float combine(double queryScore, double funcScore, double maxBoost);
public static float toFloat(double input) {
assert deviation(input) <= 0.001 : "input " + input + " out of float scope for function score deviation: " + deviation(input);
return (float) input;
}
private static double deviation(double input) { // only with assert!
float floatVersion = (float) input;
return Double.compare(floatVersion, input) == 0 || input == 0.0d ? 0 : 1.d - (floatVersion) / input;
}
public abstract Explanation explain(Explanation queryExpl, Explanation funcExpl, float maxBoost);
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeVInt(this.ordinal());
}
public static CombineFunction readFromStream(StreamInput in) throws IOException {
int ordinal = in.readVInt();
if (ordinal < 0 || ordinal >= values().length) {
throw new IOException("Unknown CombineFunction ordinal [" + ordinal + "]");
}
return values()[ordinal];
}
public static CombineFunction fromString(String combineFunction) {
return valueOf(combineFunction.toUpperCase(Locale.ROOT));
}
}