137 lines
5.0 KiB
C++
137 lines
5.0 KiB
C++
// Copyright 2010-2025 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]
|
|
#include <cstdint>
|
|
#include <cstdlib>
|
|
#include <sstream>
|
|
#include <vector>
|
|
|
|
#include "ortools/base/logging.h"
|
|
#include "ortools/constraint_solver/constraint_solver.h"
|
|
#include "ortools/constraint_solver/routing.h"
|
|
#include "ortools/constraint_solver/routing_enums.pb.h"
|
|
#include "ortools/constraint_solver/routing_index_manager.h"
|
|
#include "ortools/constraint_solver/routing_parameters.h"
|
|
// [END import]
|
|
|
|
namespace operations_research {
|
|
// [START data_model]
|
|
struct DataModel {
|
|
const std::vector<std::vector<int64_t>> distance_matrix{
|
|
{0, 2451, 713, 1018, 1631, 1374, 2408, 213, 2571, 875, 1420, 2145, 1972},
|
|
{2451, 0, 1745, 1524, 831, 1240, 959, 2596, 403, 1589, 1374, 357, 579},
|
|
{713, 1745, 0, 355, 920, 803, 1737, 851, 1858, 262, 940, 1453, 1260},
|
|
{1018, 1524, 355, 0, 700, 862, 1395, 1123, 1584, 466, 1056, 1280, 987},
|
|
{1631, 831, 920, 700, 0, 663, 1021, 1769, 949, 796, 879, 586, 371},
|
|
{1374, 1240, 803, 862, 663, 0, 1681, 1551, 1765, 547, 225, 887, 999},
|
|
{2408, 959, 1737, 1395, 1021, 1681, 0, 2493, 678, 1724, 1891, 1114, 701},
|
|
{213, 2596, 851, 1123, 1769, 1551, 2493, 0, 2699, 1038, 1605, 2300, 2099},
|
|
{2571, 403, 1858, 1584, 949, 1765, 678, 2699, 0, 1744, 1645, 653, 600},
|
|
{875, 1589, 262, 466, 796, 547, 1724, 1038, 1744, 0, 679, 1272, 1162},
|
|
{1420, 1374, 940, 1056, 879, 225, 1891, 1605, 1645, 679, 0, 1017, 1200},
|
|
{2145, 357, 1453, 1280, 586, 887, 1114, 2300, 653, 1272, 1017, 0, 504},
|
|
{1972, 579, 1260, 987, 371, 999, 701, 2099, 600, 1162, 1200, 504, 0},
|
|
};
|
|
const int num_vehicles = 1;
|
|
const RoutingIndexManager::NodeIndex depot{0};
|
|
};
|
|
// [END data_model]
|
|
|
|
// [START solution_printer]
|
|
//! @brief Print the solution.
|
|
//! @param[in] manager Index manager used.
|
|
//! @param[in] routing Routing solver used.
|
|
//! @param[in] solution Solution found by the solver.
|
|
void PrintSolution(const RoutingIndexManager& manager,
|
|
const RoutingModel& routing, const Assignment& solution) {
|
|
// Inspect solution.
|
|
LOG(INFO) << "Objective: " << solution.ObjectiveValue() << " miles";
|
|
int64_t index = routing.Start(0);
|
|
LOG(INFO) << "Route:";
|
|
int64_t distance{0};
|
|
std::stringstream route;
|
|
while (!routing.IsEnd(index)) {
|
|
route << manager.IndexToNode(index).value() << " -> ";
|
|
const int64_t previous_index = index;
|
|
index = solution.Value(routing.NextVar(index));
|
|
distance += routing.GetArcCostForVehicle(previous_index, index, int64_t{0});
|
|
}
|
|
LOG(INFO) << route.str() << manager.IndexToNode(index).value();
|
|
LOG(INFO) << "Route distance: " << distance << "miles";
|
|
LOG(INFO) << "";
|
|
LOG(INFO) << "Advanced usage:";
|
|
LOG(INFO) << "Problem solved in " << routing.solver()->wall_time() << "ms";
|
|
}
|
|
// [END solution_printer]
|
|
|
|
void Tsp() {
|
|
// Instantiate the data problem.
|
|
// [START data]
|
|
DataModel data;
|
|
// [END data]
|
|
|
|
// Create Routing Index Manager
|
|
// [START index_manager]
|
|
RoutingIndexManager manager(data.distance_matrix.size(), data.num_vehicles,
|
|
data.depot);
|
|
// [END index_manager]
|
|
|
|
// Create Routing Model.
|
|
// [START routing_model]
|
|
RoutingModel routing(manager);
|
|
// [END routing_model]
|
|
|
|
// [START transit_callback]
|
|
const int transit_callback_index = routing.RegisterTransitCallback(
|
|
[&data, &manager](const int64_t from_index,
|
|
const int64_t to_index) -> int64_t {
|
|
// Convert from routing variable Index to distance matrix NodeIndex.
|
|
const int from_node = manager.IndexToNode(from_index).value();
|
|
const int to_node = manager.IndexToNode(to_index).value();
|
|
return data.distance_matrix[from_node][to_node];
|
|
});
|
|
// [END transit_callback]
|
|
|
|
// Define cost of each arc.
|
|
// [START arc_cost]
|
|
routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index);
|
|
// [END arc_cost]
|
|
|
|
// Setting first solution heuristic.
|
|
// [START parameters]
|
|
RoutingSearchParameters searchParameters = DefaultRoutingSearchParameters();
|
|
searchParameters.set_first_solution_strategy(
|
|
FirstSolutionStrategy::PATH_CHEAPEST_ARC);
|
|
// [END parameters]
|
|
|
|
// Solve the problem.
|
|
// [START solve]
|
|
const Assignment* solution = routing.SolveWithParameters(searchParameters);
|
|
// [END solve]
|
|
|
|
// Print solution on console.
|
|
// [START print_solution]
|
|
PrintSolution(manager, routing, *solution);
|
|
// [END print_solution]
|
|
}
|
|
|
|
} // namespace operations_research
|
|
|
|
int main(int /*argc*/, char* /*argv*/[]) {
|
|
operations_research::Tsp();
|
|
return EXIT_SUCCESS;
|
|
}
|
|
// [END program]
|