Lucene example source code file (SweetSpotSimilarityTest.java)

This example Lucene source code file (SweetSpotSimilarityTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

defaultsimilarity, defaultsimilarity, fieldinvertstate, fieldinvertstate, lucenetestcase, max, mid, min, override, similarity, similarity, sweetspotsimilarity, sweetspotsimilarity, sweetspotsimilaritytest

The Lucene SweetSpotSimilarityTest.java source code

/**
 * 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.misc;

import org.apache.lucene.search.DefaultSimilarity;
import org.apache.lucene.search.Similarity;
import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.index.FieldInvertState;

/**
 * Test of the SweetSpotSimilarity
 */
public class SweetSpotSimilarityTest extends LuceneTestCase {

  public void testSweetSpotComputeNorm() {
  
    SweetSpotSimilarity ss = new SweetSpotSimilarity();
    ss.setLengthNormFactors(1,1,0.5f);

    Similarity d = new DefaultSimilarity();
    Similarity s = ss;


    // base case, should degrade
    final FieldInvertState invertState = new FieldInvertState();
    invertState.setBoost(1.0f);
    for (int i = 1; i < 1000; i++) {
      invertState.setLength(i);
      assertEquals("base case: i="+i,
                   d.computeNorm("foo", invertState),
                   s.computeNorm("foo", invertState),
                   0.0f);
    }

    // make a sweet spot
  
    ss.setLengthNormFactors(3,10,0.5f);
  
    for (int i = 3; i <=10; i++) {
      invertState.setLength(i);
      assertEquals("3,10: spot i="+i,
                   1.0f,
                   s.computeNorm("foo", invertState),
                   0.0f);
    }
  
    for (int i = 10; i < 1000; i++) {
      invertState.setLength(i-9);
      final float normD = d.computeNorm("foo", invertState);
      invertState.setLength(i);
      final float normS = s.computeNorm("foo", invertState);
      assertEquals("3,10: 10<x : i="+i,
                   normD,
                   normS,
                   0.0f);
    }


    // seperate sweet spot for certain fields

    ss.setLengthNormFactors("bar",8,13, 0.5f, false);
    ss.setLengthNormFactors("yak",6,9, 0.5f, false);

  
    for (int i = 3; i <=10; i++) {
      invertState.setLength(i);
      assertEquals("f: 3,10: spot i="+i,
                   1.0f,
                   s.computeNorm("foo", invertState),
                   0.0f);
    }
    for (int i = 10; i < 1000; i++) {
      invertState.setLength(i-9);
      final float normD = d.computeNorm("foo", invertState);
      invertState.setLength(i);
      final float normS = s.computeNorm("foo", invertState);
      assertEquals("f: 3,10: 10<x : i="+i,
                   normD,
                   normS,
                   0.0f);
    }
    for (int i = 8; i <=13; i++) {
      invertState.setLength(i);
      assertEquals("f: 8,13: spot i="+i,
                   1.0f,
                   s.computeNorm("bar", invertState),
                   0.0f);
    }
    for (int i = 6; i <=9; i++) {
      invertState.setLength(i);
      assertEquals("f: 6,9: spot i="+i,
                   1.0f,
                   s.computeNorm("yak", invertState),
                   0.0f);
    }
    for (int i = 13; i < 1000; i++) {
      invertState.setLength(i-12);
      final float normD = d.computeNorm("foo", invertState);
      invertState.setLength(i);
      final float normS = s.computeNorm("bar", invertState);
      assertEquals("f: 8,13: 13<x : i="+i,
                   normD,
                   normS,
                   0.0f);
    }
    for (int i = 9; i < 1000; i++) {
      invertState.setLength(i-8);
      final float normD = d.computeNorm("foo", invertState);
      invertState.setLength(i);
      final float normS = s.computeNorm("yak", invertState);
      assertEquals("f: 6,9: 9<x : i="+i,
                   normD,
                   normS,
                   0.0f);
    }


    // steepness

    ss.setLengthNormFactors("a",5,8,0.5f, false);
    ss.setLengthNormFactors("b",5,8,0.1f, false);

    for (int i = 9; i < 1000; i++) {
      invertState.setLength(i);
      final float normSS = ss.computeNorm("a", invertState);
      final float normS = s.computeNorm("b", invertState);
      assertTrue("s: i="+i+" : a="+normSS+
                 " < b="+normS,
                 normSS < normS);
    }

  }

  public void testSweetSpotTf() {
  
    SweetSpotSimilarity ss = new SweetSpotSimilarity();

    Similarity d = new DefaultSimilarity();
    Similarity s = ss;
    
    // tf equal

    ss.setBaselineTfFactors(0.0f, 0.0f);
  
    for (int i = 1; i < 1000; i++) {
      assertEquals("tf: i="+i,
                   d.tf(i), s.tf(i), 0.0f);
    }

    // tf higher
  
    ss.setBaselineTfFactors(1.0f, 0.0f);
  
    for (int i = 1; i < 1000; i++) {
      assertTrue("tf: i="+i+" : d="+d.tf(i)+
                 " < s="+s.tf(i),
                 d.tf(i) < s.tf(i));
    }

    // tf flat
  
    ss.setBaselineTfFactors(1.0f, 6.0f);
    for (int i = 1; i <=6; i++) {
      assertEquals("tf flat1: i="+i, 1.0f, s.tf(i), 0.0f);
    }
    ss.setBaselineTfFactors(2.0f, 6.0f);
    for (int i = 1; i <=6; i++) {
      assertEquals("tf flat2: i="+i, 2.0f, s.tf(i), 0.0f);
    }
    for (int i = 6; i <=1000; i++) {
      assertTrue("tf: i="+i+" : s="+s.tf(i)+
                 " < d="+d.tf(i),
                 s.tf(i) < d.tf(i));
    }

    // stupidity
    assertEquals("tf zero", 0.0f, s.tf(0), 0.0f);
  }

  public void testHyperbolicSweetSpot() {
  
    SweetSpotSimilarity ss = new SweetSpotSimilarity() {
        @Override
        public float tf(int freq) {
          return hyperbolicTf(freq);
        }
      };
    ss.setHyperbolicTfFactors(3.3f, 7.7f, Math.E, 5.0f);
    
    Similarity s = ss;

    for (int i = 1; i <=1000; i++) {
      assertTrue("MIN tf: i="+i+" : s="+s.tf(i),
                 3.3f <= s.tf(i));
      assertTrue("MAX tf: i="+i+" : s="+s.tf(i),
                 s.tf(i) <= 7.7f);
    }
    assertEquals("MID tf", 3.3f+(7.7f - 3.3f)/2.0f, s.tf(5), 0.00001f);
    
    // stupidity
    assertEquals("tf zero", 0.0f, s.tf(0), 0.0f);
    
  }

  
}