| /* |
| * 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. |
| */ |
| package org.apache.lucene.search.similarities; |
| |
| |
| 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 double scoreTimes1pTfn(BasicStats stats) { |
| return 1.0; |
| } |
| |
| @Override |
| public final Explanation explain(BasicStats stats, double tfn) { |
| return Explanation.match( |
| (float) (scoreTimes1pTfn(stats) / (1 + tfn)), |
| getClass().getSimpleName() + ", computed as 1 / (tfn + 1) from:", |
| Explanation.match((float) tfn, "tfn, normalized term frequency")); |
| } |
| |
| @Override |
| public String toString() { |
| return "L"; |
| } |
| } |