| /* |
| * 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 opennlp.tools.languagemodel; |
| |
| import java.util.Collection; |
| |
| import opennlp.tools.util.StringList; |
| import org.junit.Test; |
| |
| import static org.junit.Assert.assertTrue; |
| |
| /** |
| * Tests for evaluating accuracy of language models |
| */ |
| public class LanguageModelEvaluationTest { |
| |
| @Test |
| public void testPerplexityComparison() throws Exception { |
| |
| Collection<StringList> trainingVocabulary = LanguageModelTestUtils.generateRandomVocabulary(1100000); |
| Collection<StringList> testVocabulary = LanguageModelTestUtils.generateRandomVocabulary(100); |
| |
| NGramLanguageModel unigramLM = new NGramLanguageModel(1); |
| for (StringList sentence : trainingVocabulary) { |
| unigramLM.add(sentence, 1, 1); |
| } |
| double unigramPerplexity = LanguageModelTestUtils.getPerplexity(unigramLM, testVocabulary, 1); |
| |
| NGramLanguageModel bigramLM = new NGramLanguageModel(2); |
| for (StringList sentence : trainingVocabulary) { |
| bigramLM.add(sentence, 1, 2); |
| } |
| double bigramPerplexity = LanguageModelTestUtils.getPerplexity(bigramLM, testVocabulary, 2); |
| assertTrue(unigramPerplexity >= bigramPerplexity); |
| |
| NGramLanguageModel trigramLM = new NGramLanguageModel(3); |
| for (StringList sentence : trainingVocabulary) { |
| trigramLM.add(sentence, 2, 3); |
| } |
| double trigramPerplexity = LanguageModelTestUtils.getPerplexity(trigramLM, testVocabulary, 3); |
| assertTrue(bigramPerplexity >= trigramPerplexity); |
| |
| } |
| |
| } |