CPHExperiment.java

package cph;
import cph.instance.CPHInstance;
import cph.instance.CPHInstancesManager;
import cph.algorithm.CPHRandomConstructive;

import java.io.IOException;

import jmh.algorithm.MultiStartSearch;
import jmh.algorithm.MultiStartSearch.MSConfig;
import jmh.algorithm.Objective;
import jmh.algorithm.Solution;
import jmh.experiment.ExperimentManager;
import jmh.instance.FormatException;

/**
 * Runs the Capacitated p-hub experiment: for every {@code phub_50_5} instance it
 * compares the four multi-start configurations and reports the results. CPH is a
 * minimization problem.
 *
 * <p>Only the problem-specific wiring lives here (instance type, constructive and
 * objective); everything else is the shared framework.
 */
public class CPHExperiment {

    private static final long TIMEOUT_MILLIS = 10 * 1000;

    public static void main(String[] args) throws IOException, FormatException {

        var instancesManager = new CPHInstancesManager();
        var instances = instancesManager.getInstancesByType("phub_50_5");

        var manager = new ExperimentManager(Objective.MINIMIZE);

        for (var instanceFile : instances) {

            CPHInstance instance = instanceFile.loadInstance();
            Solution solution;

            solution = search(instance, MSConfig.RANDOM);
            manager.addSolution(instance, "Random", solution);

            solution = search(instance, MSConfig.FIRST_IMPROVEMENT_RANDOM);
            manager.addSolution(instance, "First Improvement Random", solution);

            solution = search(instance, MSConfig.FIRST_IMPROVEMENT_LEXICOGRAPHICAL);
            manager.addSolution(instance, "First Improvement Lexicographical", solution);

            solution = search(instance, MSConfig.BEST_IMPROVEMENT);
            manager.addSolution(instance, "Best Improvement", solution);
        }

        manager.experimentFinished();
    }

    private static Solution search(CPHInstance instance, MSConfig config) {
        return new MultiStartSearch(new CPHRandomConstructive(instance), config, Objective.MINIMIZE)
                .calculateSolution(TIMEOUT_MILLIS);
    }

}