org.apache.lucene.search.similarities.AfterEffectL Maven / Gradle / Ivy
package org.apache.lucene.search.similarities;
/*
* 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.
*/
import org.apache.lucene.search.Explanation;
/**
* Model of the information gain based on Laplace's law of succession.
* @lucene.experimental
*/
public class AfterEffectL extends AfterEffect {
/** Sole constructor: parameter-free */
public AfterEffectL() {}
@Override
public final float score(BasicStats stats, float tfn) {
return 1 / (tfn + 1);
}
@Override
public final Explanation explain(BasicStats stats, float tfn) {
return Explanation.match(
score(stats, tfn),
getClass().getSimpleName() + ", computed from: ",
Explanation.match(tfn, "tfn"));
}
@Override
public String toString() {
return "L";
}
}