| /* |
| * 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.opennlp.utils.ngram; |
| |
| import java.util.Collection; |
| import java.util.LinkedList; |
| import org.junit.Test; |
| |
| import static org.junit.Assert.assertEquals; |
| import static org.junit.Assert.assertNotNull; |
| import static org.junit.Assert.assertTrue; |
| |
| /** |
| * Testcase for {@link org.apache.opennlp.utils.ngram.NGramUtils} |
| */ |
| public class NGramUtilsTest { |
| @Test |
| public void testBigram() { |
| Collection<String[]> set = new LinkedList<String[]>(); |
| set.add(new String[]{"<s>","I","am","Sam","</s>"}); |
| set.add(new String[]{"<s>","Sam","I","am","</s>"}); |
| set.add(new String[]{"<s>","I","do","not","like","green","eggs","and","ham","</s>"}); |
| set.add(new String[]{}); |
| Double d = NGramUtils.calculateBigramMLProbability("I", "<s>", set); |
| assertTrue(d>0); |
| assertEquals(Double.valueOf(0.6666666666666666d),d); |
| d = NGramUtils.calculateBigramMLProbability("</s>", "Sam", set); |
| assertEquals(Double.valueOf(0.5d),d); |
| d = NGramUtils.calculateBigramMLProbability("Sam", "<s>", set); |
| assertEquals(Double.valueOf(0.3333333333333333d),d); |
| } |
| |
| @Test |
| public void testTrigram() { |
| Collection<String[]> set = new LinkedList<String[]>(); |
| set.add(new String[]{"<s>","I","am","Sam","</s>"}); |
| set.add(new String[]{"<s>","Sam","I","am","</s>"}); |
| set.add(new String[]{"<s>","I","do","not","like","green","eggs","and","ham","</s>"}); |
| set.add(new String[]{}); |
| Double d = NGramUtils.calculateTrigramMLProbability("I", "am", "Sam",set); |
| assertTrue(d>0); |
| assertEquals(Double.valueOf(0.5),d); |
| d = NGramUtils.calculateTrigramMLProbability("Sam","I", "am", set); |
| assertEquals(Double.valueOf(1d),d); |
| } |
| |
| @Test |
| public void testLinearInterpolation() throws Exception { |
| Collection<String[]> set = new LinkedList<String[]>(); |
| set.add(new String[]{"the","green","book","STOP"}); |
| set.add(new String[]{"my","blue","book","STOP"}); |
| set.add(new String[]{"his","green","house","STOP"}); |
| set.add(new String[]{"book","STOP"}); |
| Double lambda = 1d/3d; |
| Double d = NGramUtils.calculateLinearInterpolationProbability("the", "green", "book", set, lambda, lambda, lambda); |
| assertNotNull(d); |
| assertTrue(d > 0); |
| assertEquals("wrong result", Double.valueOf(0.5714285714285714d), d); |
| } |
| |
| @Test |
| public void testLinearInterpolation2() throws Exception { |
| Collection<String[]> set = new LinkedList<String[]>(); |
| set.add(new String[]{"D","N","V","STOP"}); |
| set.add(new String[]{"D","N","V","STOP"}); |
| Double lambda = 1d/3d; |
| Double d = NGramUtils.calculateLinearInterpolationProbability("N", "V", "STOP", set, lambda, lambda, lambda); |
| assertNotNull(d); |
| assertTrue(d > 0); |
| assertEquals("wrong result", Double.valueOf(0.75d), d); |
| } |
| |
| } |