jmetal最简示例

这个示例展示了如何使用 JMetal 进行简单的多目标优化问题。你可以根据需要修改问题、算法参数和算子来适应不同的优化问题。

重点:

• 问题定义示例可以参考 ZDT1
• 求解器主函数可以参考 NSGAIIRunner

代码解释：

• 定义问题：这里我们使用 ZDT1 问题，它是一个经典的双目标优化问题。
• 定义算法：使用 NSGA-II 算法，并设置种群大小和迭代次数。
• 设置交叉和变异算子：这里使用 SBX 交叉和多项式变异。
• 设置选择算子：使用二进制锦标赛选择。
• 运行算法：执行算法并记录执行时间。
• 打印结果：打印每个解的详细信息。
• 输出结果到文件：将结果输出到文件中。

package aaaaaaa;import java.util.List;import org.uma.jmetal.algorithm.Algorithm;
import org.uma.jmetal.algorithm.examples.AlgorithmRunner;
import org.uma.jmetal.algorithm.multiobjective.nsgaii.NSGAIIBuilder;
import org.uma.jmetal.operator.crossover.CrossoverOperator;
import org.uma.jmetal.operator.crossover.impl.SBXCrossover;
import org.uma.jmetal.operator.mutation.MutationOperator;
import org.uma.jmetal.operator.mutation.impl.PolynomialMutation;
import org.uma.jmetal.operator.selection.SelectionOperator;
import org.uma.jmetal.operator.selection.impl.BinaryTournamentSelection;
import org.uma.jmetal.problem.Problem;
import org.uma.jmetal.problem.multiobjective.zdt.ZDT1;
import org.uma.jmetal.solution.doublesolution.DoubleSolution;
import org.uma.jmetal.util.JMetalLogger;
import org.uma.jmetal.util.comparator.RankingAndCrowdingDistanceComparator;public class App {public static void main(String[] args) {// 1. 定义问题Problem<DoubleSolution> problem = new ZDT1();// 2. 设置交叉和变异算子 和 设置选择算子double crossoverProbability = 0.9;double crossoverDistributionIndex = 20.0;CrossoverOperator<DoubleSolution> crossover = new SBXCrossover(crossoverProbability,crossoverDistributionIndex);double mutationProbability = 1.0 / problem.numberOfVariables();double mutationDistributionIndex = 20.0;MutationOperator<DoubleSolution> mutation = new PolynomialMutation(mutationProbability,mutationDistributionIndex);SelectionOperator<List<DoubleSolution>, DoubleSolution> selection = new BinaryTournamentSelection<>(new RankingAndCrowdingDistanceComparator<>());// 3. 迭代次数和种群大小int populationSize = 100;// 4. 定义算法（NSGA-II）Algorithm<List<DoubleSolution>> algorithm = new NSGAIIBuilder<>(problem, crossover, mutation, populationSize).setSelectionOperator(selection).setMaxEvaluations(25000).build();// 5. 运行算法long initTime = System.currentTimeMillis();AlgorithmRunner algorithmRunner = new AlgorithmRunner.Executor(algorithm).execute();List<DoubleSolution> solutionSet = algorithm.result();long endTime = System.currentTimeMillis();// 6. 打印结果JMetalLogger.logger.info("Total execution time: " + (endTime - initTime) + "ms");// 7. 打印非支配排序结果for (DoubleSolution solution : solutionSet) {JMetalLogger.logger.info("Solution: " + solution);}// 8. 输出结果 List<DoubleSolution> population = algorithm.result();long computingTime = algorithmRunner.getComputingTime();JMetalLogger.logger.info("Total execution time: " + computingTime + "ms");}}

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>sss</groupId><artifactId>aaaaaaa</artifactId><version>0.0.1-SNAPSHOT</version><dependencies> <dependency><groupId>org.uma.jmetal</groupId><artifactId>jmetal-core</artifactId><version>6.6</version></dependency>   <dependency><groupId>org.uma.jmetal</groupId><artifactId>jmetal-algorithm</artifactId><version>6.6</version></dependency><dependency><groupId>org.uma.jmetal</groupId><artifactId>jmetal-problem</artifactId><version>6.6</version></dependency> 
</dependencies>
</project>