package org.apache.lucene.search;/** * 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. *//** Expert: Default scoring implementation. */public class DefaultSimilarity extends Similarity {  /** Implemented as <code>1/sqrt(numTerms)</code>. */  public float lengthNorm(String fieldName, int numTerms) {    return (float)(1.0 / Math.sqrt(numTerms));  }    /** Implemented as <code>1/sqrt(sumOfSquaredWeights)</code>. */  public float queryNorm(float sumOfSquaredWeights) {    return (float)(1.0 / Math.sqrt(sumOfSquaredWeights));  }  /** Implemented as <code>sqrt(freq)</code>. */  public float tf(float freq) {    return (float)Math.sqrt(freq);  }      /** Implemented as <code>1 / (distance + 1)</code>. */  public float sloppyFreq(int distance) {    return 1.0f / (distance + 1);  }      /** Implemented as <code>log(numDocs/(docFreq+1)) + 1</code>. */  public float idf(int docFreq, int numDocs) {    return (float)(Math.log(numDocs/(double)(docFreq+1)) + 1.0);  }      /** Implemented as <code>overlap / maxOverlap</code>. */  public float coord(int overlap, int maxOverlap) {    return overlap / (float)maxOverlap;  }}