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VrpWithTimeLimit.java
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VrpWithTimeLimit.java
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// Copyright 2010-2024 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// [START program]
package com.google.ortools.constraintsolver.samples;
// [START import]
import static java.lang.Math.max;
import com.google.ortools.Loader;
import com.google.ortools.constraintsolver.Assignment;
import com.google.ortools.constraintsolver.FirstSolutionStrategy;
import com.google.ortools.constraintsolver.LocalSearchMetaheuristic;
import com.google.ortools.constraintsolver.RoutingDimension;
import com.google.ortools.constraintsolver.RoutingIndexManager;
import com.google.ortools.constraintsolver.RoutingModel;
import com.google.ortools.constraintsolver.RoutingSearchParameters;
import com.google.ortools.constraintsolver.main;
import com.google.protobuf.Duration;
import java.util.logging.Logger;
// [END import]
/** Minimal VRP. */
public final class VrpWithTimeLimit {
private static final Logger logger = Logger.getLogger(VrpWithTimeLimit.class.getName());
// [START solution_printer]
/// @brief Print the solution.
static void printSolution(
RoutingIndexManager manager, RoutingModel routing, Assignment solution) {
// Solution cost.
logger.info("Objective : " + solution.objectiveValue());
// Inspect solution.
long maxRouteDistance = 0;
for (int i = 0; i < manager.getNumberOfVehicles(); ++i) {
long index = routing.start(i);
logger.info("Route for Vehicle " + i + ":");
long routeDistance = 0;
String route = "";
while (!routing.isEnd(index)) {
route += manager.indexToNode(index) + " -> ";
long previousIndex = index;
index = solution.value(routing.nextVar(index));
routeDistance += routing.getArcCostForVehicle(previousIndex, index, i);
}
logger.info(route + manager.indexToNode(index));
logger.info("Distance of the route: " + routeDistance + "m");
maxRouteDistance = max(routeDistance, maxRouteDistance);
}
logger.info("Maximum of the route distances: " + maxRouteDistance + "m");
}
// [END solution_printer]
public static void main(String[] args) {
Loader.loadNativeLibraries();
// Instantiate the data problem.
// [START data]
final int locationNumber = 20;
final int vehicleNumber = 5;
final int depot = 0;
// [END data]
// Create Routing Index Manager
// [START index_manager]
RoutingIndexManager manager = new RoutingIndexManager(locationNumber, vehicleNumber, depot);
// [END index_manager]
// Create Routing Model.
// [START routing_model]
RoutingModel routing = new RoutingModel(manager);
// [END routing_model]
// Create and register a transit callback.
// [START transit_callback]
final int transitCallbackIndex =
routing.registerTransitCallback((long fromIndex, long toIndex) -> 1);
// [END transit_callback]
// Define cost of each arc.
// [START arc_cost]
routing.setArcCostEvaluatorOfAllVehicles(transitCallbackIndex);
// [END arc_cost]
// Add Distance constraint.
// [START distance_constraint]
routing.addDimension(transitCallbackIndex,
/*slack_max=*/0,
/*capacity=*/3000,
/*fix_start_cumul_to_zero=*/true, "Distance");
RoutingDimension distanceDimension = routing.getMutableDimension("Distance");
distanceDimension.setGlobalSpanCostCoefficient(100);
// [END distance_constraint]
// Setting first solution heuristic.
// [START parameters]
RoutingSearchParameters searchParameters =
main.defaultRoutingSearchParameters()
.toBuilder()
.setFirstSolutionStrategy(FirstSolutionStrategy.Value.PATH_CHEAPEST_ARC)
.setLocalSearchMetaheuristic(LocalSearchMetaheuristic.Value.GUIDED_LOCAL_SEARCH)
.setLogSearch(true)
.setTimeLimit(Duration.newBuilder().setSeconds(5).build())
.build();
// [END parameters]
// Solve the problem.
// [START solve]
Assignment solution = routing.solveWithParameters(searchParameters);
// [END solve]
// Print solution on console.
// [START print_solution]
printSolution(manager, routing, solution);
// [END print_solution]
}
private VrpWithTimeLimit() {}
}
// [END program]