001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.math.genetics;
018    
019    import static org.junit.Assert.*;
020    import org.junit.Test;
021    
022    public class OnePointCrossoverTest {
023    
024        @Test
025        public void testCrossover() {
026            Integer[] p1 = new Integer[] {1,0,1,0,0,1,0,1,1};
027            Integer[] p2 = new Integer[] {0,1,1,0,1,0,1,1,1};
028            
029            BinaryChromosome p1c = new DummyBinaryChromosome(p1);
030            BinaryChromosome p2c = new DummyBinaryChromosome(p2);
031            
032            OnePointCrossover<Integer> opc = new OnePointCrossover<Integer>();
033            
034            // how to test a stochastic method?
035            for (int i=0; i<20; i++) {
036                ChromosomePair pair = opc.crossover(p1c,p2c);
037                
038                Integer[] c1 = new Integer[p1.length];
039                Integer[] c2 = new Integer[p2.length];
040                
041                c1 = ((BinaryChromosome) pair.getFirst()).getRepresentation().toArray(c1);
042                c2 = ((BinaryChromosome) pair.getSecond()).getRepresentation().toArray(c2);
043                
044                // first and last values will be the same
045                assertEquals((int) p1[0], (int) c1[0]);
046                assertEquals((int) p2[0], (int) c2[0]);
047                assertEquals((int) p1[p1.length-1], (int) c1[c1.length-1]);
048                assertEquals((int) p2[p2.length-1], (int) c2[c2.length-1]);
049                // moreover, in the above setting, the 2nd, 3rd and 7th values will be the same
050                assertEquals((int) p1[2], (int) c1[2]);
051                assertEquals((int) p2[2], (int) c2[2]);
052                assertEquals((int) p1[3], (int) c1[3]);
053                assertEquals((int) p2[3], (int) c2[3]);
054                assertEquals((int) p1[7], (int) c1[7]);
055                assertEquals((int) p2[7], (int) c2[7]);
056            }
057        }
058    
059    }