/*******************************************************************************
* 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 BuildAlgorithmFromScratch {
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;
}
}