[英]How to install Google OR-Tools for an IntelliJ project on macOS
I'm trying to run the VRP Java examples for Google OR-Tools but keep getting an UnsatisfiedLinkError: no jniortools in java.library.path
error.我正在尝试为 Google OR-Tools 运行 VRP Java 示例,但不断收到
UnsatisfiedLinkError: no jniortools in java.library.path
错误。
What I've done is:我所做的是:
lib
in the root of the projectlib
文件夹com.google.ortools.jar
and protobuf.jar
(found in the lib
folder of the binary distribution downloaded in step 1) to the lib
folder created in step 3.com.google.ortools.jar
和protobuf.jar
的 Goole OR-Tools 文件(在步骤 1 中下载的二进制发行版的lib
文件夹中找到)复制并粘贴到步骤 3 中创建的lib
文件夹中。com.google.ortools.jar
and protobuf.jar
from {project_root}/lib
{project_root}/lib
选择com.google.ortools.jar
和protobuf.jar
This is the full code of the java example:这是java示例的完整代码:
// Copyright 2010-2018 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]
// [START import]
import com.google.ortools.constraintsolver.Assignment;
import com.google.ortools.constraintsolver.FirstSolutionStrategy;
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 java.util.logging.Logger;
// [END import]
/** Minimal VRP.*/
public class VrpGlobalSpan {
static {
System.loadLibrary("jniortools");
}
private static final Logger logger = Logger.getLogger(VrpGlobalSpan.class.getName());
// [START data_model]
static class DataModel {
public final long[][] distanceMatrix = {
{0, 548, 776, 696, 582, 274, 502, 194, 308, 194, 536, 502, 388, 354, 468, 776, 662},
{548, 0, 684, 308, 194, 502, 730, 354, 696, 742, 1084, 594, 480, 674, 1016, 868, 1210},
{776, 684, 0, 992, 878, 502, 274, 810, 468, 742, 400, 1278, 1164, 1130, 788, 1552, 754},
{696, 308, 992, 0, 114, 650, 878, 502, 844, 890, 1232, 514, 628, 822, 1164, 560, 1358},
{582, 194, 878, 114, 0, 536, 764, 388, 730, 776, 1118, 400, 514, 708, 1050, 674, 1244},
{274, 502, 502, 650, 536, 0, 228, 308, 194, 240, 582, 776, 662, 628, 514, 1050, 708},
{502, 730, 274, 878, 764, 228, 0, 536, 194, 468, 354, 1004, 890, 856, 514, 1278, 480},
{194, 354, 810, 502, 388, 308, 536, 0, 342, 388, 730, 468, 354, 320, 662, 742, 856},
{308, 696, 468, 844, 730, 194, 194, 342, 0, 274, 388, 810, 696, 662, 320, 1084, 514},
{194, 742, 742, 890, 776, 240, 468, 388, 274, 0, 342, 536, 422, 388, 274, 810, 468},
{536, 1084, 400, 1232, 1118, 582, 354, 730, 388, 342, 0, 878, 764, 730, 388, 1152, 354},
{502, 594, 1278, 514, 400, 776, 1004, 468, 810, 536, 878, 0, 114, 308, 650, 274, 844},
{388, 480, 1164, 628, 514, 662, 890, 354, 696, 422, 764, 114, 0, 194, 536, 388, 730},
{354, 674, 1130, 822, 708, 628, 856, 320, 662, 388, 730, 308, 194, 0, 342, 422, 536},
{468, 1016, 788, 1164, 1050, 514, 514, 662, 320, 274, 388, 650, 536, 342, 0, 764, 194},
{776, 868, 1552, 560, 674, 1050, 1278, 742, 1084, 810, 1152, 274, 388, 422, 764, 0, 798},
{662, 1210, 754, 1358, 1244, 708, 480, 856, 514, 468, 354, 844, 730, 536, 194, 798, 0},
};
public final int vehicleNumber = 4;
public final int depot = 0;
}
// [END data_model]
// [START solution_printer]
/// @brief Print the solution.
static void printSolution(
DataModel data, RoutingModel routing, RoutingIndexManager manager, Assignment solution) {
// Inspect solution.
long maxRouteDistance = 0;
for (int i = 0; i < data.vehicleNumber; ++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 = Math.max(routeDistance, maxRouteDistance);
}
logger.info("Maximum of the route distances: " + maxRouteDistance + "m");
}
// [END solution_printer]
public static void main(String[] args) throws Exception {
// Instantiate the data problem.
// [START data]
final DataModel data = new DataModel();
// [END data]
// Create Routing Index Manager
// [START index_manager]
RoutingIndexManager manager =
new RoutingIndexManager(data.distanceMatrix.length, data.vehicleNumber, data.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) -> {
// Convert from routing variable Index to user NodeIndex.
int fromNode = manager.indexToNode(fromIndex);
int toNode = manager.indexToNode(toIndex);
return data.distanceMatrix[fromNode][toNode];
});
// [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, 0, 3000,
true, // start cumul to zero
"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)
.build();
// [END parameters]
// Solve the problem.
// [START solve]
Assignment solution = routing.solveWithParameters(searchParameters);
// [END solve]
// Print solution on console.
// [START print_solution]
printSolution(data, routing, manager, solution);
// [END print_solution]
}
}
// [END program]
The com.google.ortools.*
imports are fine but I get the following error when running the java example: com.google.ortools.*
导入很好,但在运行 java 示例时出现以下错误:
Exception in thread "main" java.lang.UnsatisfiedLinkError: no jniortools in java.library.path
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1867)
at java.lang.Runtime.loadLibrary0(Runtime.java:870)
at java.lang.System.loadLibrary(System.java:1122)
at VrpGlobalSpan.<clinit>(VrpGlobalSpan.java:29)
I've searched for the jniortools
file but can't find it anywhere.我已经搜索了
jniortools
文件,但在任何地方都找不到。 What can I do to make sure the example runs?我该怎么做才能确保示例运行?
All the libs, including libjniortools.dylib are in the lib directory, You need to add the path to installed lib directory in intellij.所有的libs,包括libjniortools.dylib都在lib目录下,你需要在intellij中添加安装lib目录的路径。
See How to set the java.library.path in intelliJ Idea请参阅如何在 intelliJ Idea 中设置 java.library.path
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