Package jsprit.examples

Source Code of jsprit.examples.BuildAlgorithmFromScratchWithHardAndSoftConstraints

/*******************************************************************************
* Copyright (C) 2014  Stefan Schroeder
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3.0 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library.  If not, see <http://www.gnu.org/licenses/>.
******************************************************************************/
package jsprit.examples;

import jsprit.core.algorithm.*;
import jsprit.core.algorithm.acceptor.GreedyAcceptance;
import jsprit.core.algorithm.module.RuinAndRecreateModule;
import jsprit.core.algorithm.recreate.BestInsertionBuilder;
import jsprit.core.algorithm.recreate.InsertionStrategy;
import jsprit.core.algorithm.ruin.RadialRuinStrategyFactory;
import jsprit.core.algorithm.ruin.RandomRuinStrategyFactory;
import jsprit.core.algorithm.ruin.RuinStrategy;
import jsprit.core.algorithm.ruin.distance.AvgServiceAndShipmentDistance;
import jsprit.core.algorithm.selector.SelectBest;
import jsprit.core.algorithm.state.StateManager;
import jsprit.core.algorithm.state.UpdateVariableCosts;
import jsprit.core.algorithm.termination.IterationWithoutImprovementTermination;
import jsprit.core.problem.VehicleRoutingProblem;
import jsprit.core.problem.constraint.ConstraintManager;
import jsprit.core.problem.solution.SolutionCostCalculator;
import jsprit.core.problem.solution.VehicleRoutingProblemSolution;
import jsprit.core.problem.vehicle.InfiniteFleetManagerFactory;
import jsprit.core.problem.vehicle.VehicleFleetManager;
import jsprit.core.reporting.SolutionPrinter;
import jsprit.core.util.Solutions;
import jsprit.instance.reader.SolomonReader;
import jsprit.util.Examples;

import java.util.Collection;

public class BuildAlgorithmFromScratchWithHardAndSoftConstraints {

  public static void main(String[] args) {
    /*
     * some preparation - create output folder
     */
    Examples.createOutputFolder();
   
    /*
     * Build the problem.
     *
     * But define a problem-builder first.
     */
    VehicleRoutingProblem.Builder vrpBuilder = VehicleRoutingProblem.Builder.newInstance();
   
    /*
     * A solomonReader reads solomon-instance files, and stores the required information in the builder.
     */
    new SolomonReader(vrpBuilder).read("input/C101_solomon.txt");
   
    /*
     * Finally, the problem can be built. By default, transportCosts are crowFlyDistances (as usually used for vrp-instances).
     */
    VehicleRoutingProblem vrp = vrpBuilder.build();
   
    /*
     * Build algorithm
     */
    VehicleRoutingAlgorithm vra = buildAlgorithmFromScratch(vrp);
   
    /*
     * search solution
     */
    Collection<VehicleRoutingProblemSolution> solutions = vra.searchSolutions();
   
    /*
     * print result
     */
    SolutionPrinter.print(Solutions.bestOf(solutions));

  }

  private static VehicleRoutingAlgorithm buildAlgorithmFromScratch(VehicleRoutingProblem vrp) {
   
    /*
     * manages route and activity states.
     */
    StateManager stateManager = new StateManager(vrp);
    /*
     * tells stateManager to update load states
     */
    stateManager.updateLoadStates();
    /*
     * tells stateManager to update time-window states
     */
    stateManager.updateTimeWindowStates();
    /*
     * stateManager.addStateUpdater(updater);
     * lets you register your own stateUpdater
     */
   
    /*
     * updates variable costs once a vehicleRoute has changed (by removing or adding a customer)
     */
    stateManager.addStateUpdater(new UpdateVariableCosts(vrp.getActivityCosts(), vrp.getTransportCosts(), stateManager));
   
    /*
     * constructs a constraintManager that manages the various hardConstraints (and soon also softConstraints)
     */
    ConstraintManager constraintManager = new ConstraintManager(vrp,stateManager);
    /*
     * tells constraintManager to add timeWindowConstraints
     */
    constraintManager.addTimeWindowConstraint();
    /*
     * tells constraintManager to add loadConstraints
     */
    constraintManager.addLoadConstraint();
    /*
     * add an arbitrary number of hardConstraints by
     * constraintManager.addConstraint(...)
     */
   
   
    /*
     * define a fleetManager, here infinite vehicles can be used
     */
    VehicleFleetManager fleetManager = new InfiniteFleetManagerFactory(vrp.getVehicles()).createFleetManager();
   
    /*
     * define ruin-and-recreate strategies
     *
     */
    /*
     * first, define an insertion-strategy, i.e. bestInsertion
     */
    BestInsertionBuilder iBuilder = new BestInsertionBuilder(vrp, fleetManager, stateManager, constraintManager);
    /*
     * no need to set further options
     */
    InsertionStrategy iStrategy = iBuilder.build();
   
    /*
     * second, define random-ruin that ruins 50-percent of the selected solution
     */
    RuinStrategy randomRuin = new RandomRuinStrategyFactory(0.5).createStrategy(vrp);
   
    /*
     * third, define radial-ruin that ruins 30-percent of the selected solution
     * the second para defines the distance between two jobs.
     */
    RuinStrategy radialRuin = new RadialRuinStrategyFactory(0.3, new AvgServiceAndShipmentDistance(vrp.getTransportCosts())).createStrategy(vrp);
   
    /*
     * now define a strategy
     */
    /*
     * but before define how a generated solution is evaluated
     * here: the VariablePlusFixed.... comes out of the box and it does what its name suggests
     */
    SolutionCostCalculator solutionCostCalculator = new VariablePlusFixedSolutionCostCalculatorFactory(stateManager).createCalculator();
   
    SearchStrategy firstStrategy = new SearchStrategy(new SelectBest(), new GreedyAcceptance(1), solutionCostCalculator);
    firstStrategy.addModule(new RuinAndRecreateModule("randomRuinAndBestInsertion", iStrategy, randomRuin));
   
    SearchStrategy secondStrategy = new SearchStrategy(new SelectBest(), new GreedyAcceptance(1), solutionCostCalculator);
    secondStrategy.addModule(new RuinAndRecreateModule("radialRuinAndBestInsertion", iStrategy, radialRuin));
   
    /*
     * put both strategies together, each with the prob of 0.5 to be selected
     */
    SearchStrategyManager searchStrategyManager = new SearchStrategyManager();
    searchStrategyManager.addStrategy(firstStrategy, 0.5);
    searchStrategyManager.addStrategy(secondStrategy, 0.5);
   
    /*
     * construct the algorithm
     */
    VehicleRoutingAlgorithm vra = new VehicleRoutingAlgorithm(vrp, searchStrategyManager);
    //do not forgett to add the stateManager listening to the algorithm-stages
    vra.addListener(stateManager);
    //remove empty vehicles after insertion has finished
    vra.addListener(new RemoveEmptyVehicles(fleetManager));
   
    /*
     * Do not forget to add an initial solution by vra.addInitialSolution(solution);
     * or
     */
    vra.addInitialSolution(new InsertionInitialSolutionFactory(iStrategy, solutionCostCalculator).createSolution(vrp));
   
    /*
     * define the nIterations (by default nIteration=100)
     */
    vra.setMaxIterations(1000);
   
    /*
     * optionally define a premature termination criterion (by default: not criterion is set)
     */
    vra.setPrematureAlgorithmTermination(new IterationWithoutImprovementTermination(100));
   
    return vra;
  }

}
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