1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.math.genetics; 18 19 /** 20 * Stops after a fixed number of generations. Each time 21 * {@link #isSatisfied(Population)} is invoked, a generation counter is 22 * incremented. Once the counter reaches the configured 23 * <code>maxGenerations</code> value, {@link #isSatisfied(Population)} returns 24 * true. 25 * 26 * @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $ 27 * @since 2.0 28 */ 29 public class FixedGenerationCount implements StoppingCondition { 30 /** Number of generations that have passed */ 31 private int numGenerations = 0; 32 33 /** Maximum number of generations (stopping criteria) */ 34 private final int maxGenerations; 35 36 /** 37 * Create a new FixedGenerationCount instance. 38 * 39 * @param maxGenerations number of generations to evolve 40 */ 41 public FixedGenerationCount(int maxGenerations) { 42 if (maxGenerations <= 0) 43 throw new IllegalArgumentException("The number of generations has to be >= 0"); 44 this.maxGenerations = maxGenerations; 45 } 46 47 /** 48 * Determine whether or not the given number of generations have passed. 49 * Increments the number of generations counter if the maximum has not 50 * been reached. 51 * 52 * @param population ignored (no impact on result) 53 * @return <code>true</code> IFF the maximum number of generations has been exceeded 54 */ 55 public boolean isSatisfied(Population population) { 56 if (this.numGenerations < this.maxGenerations) { 57 numGenerations++; 58 return false; 59 } 60 return true; 61 } 62 63 /** 64 * @return the number of generations that have passed 65 */ 66 public int getNumGenerations() { 67 return numGenerations; 68 } 69 70 } 71
