215 lines
8.2 KiB
C++
215 lines
8.2 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 "google/protobuf/duration.pb.h"
|
|
#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, 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},
|
|
};
|
|
// [START demands_capacities]
|
|
const std::vector<int64_t> demands{
|
|
0, 1, 1, 3, 6, 3, 6, 8, 8, 1, 2, 1, 2, 6, 6, 8, 8,
|
|
};
|
|
const std::vector<int64_t> vehicle_capacities{15, 15, 15, 15};
|
|
// [END demands_capacities]
|
|
const int num_vehicles = 4;
|
|
const RoutingIndexManager::NodeIndex depot{0};
|
|
};
|
|
// [END data_model]
|
|
|
|
// [START solution_printer]
|
|
//! @brief Print the solution.
|
|
//! @param[in] data Data of the problem.
|
|
//! @param[in] manager Index manager used.
|
|
//! @param[in] routing Routing solver used.
|
|
//! @param[in] solution Solution found by the solver.
|
|
void PrintSolution(const DataModel& data, const RoutingIndexManager& manager,
|
|
const RoutingModel& routing, const Assignment& solution) {
|
|
// Display dropped nodes.
|
|
std::ostringstream dropped_nodes;
|
|
for (int64_t node = 0; node < routing.Size(); ++node) {
|
|
if (routing.IsStart(node) || routing.IsEnd(node)) continue;
|
|
if (solution.Value(routing.NextVar(node)) == node) {
|
|
dropped_nodes << " " << manager.IndexToNode(node).value();
|
|
}
|
|
}
|
|
LOG(INFO) << "Dropped nodes:" << dropped_nodes.str();
|
|
// Display routes
|
|
int64_t total_distance{0};
|
|
int64_t total_load{0};
|
|
for (int vehicle_id = 0; vehicle_id < data.num_vehicles; ++vehicle_id) {
|
|
if (!routing.IsVehicleUsed(solution, vehicle_id)) {
|
|
continue;
|
|
}
|
|
int64_t index = routing.Start(vehicle_id);
|
|
LOG(INFO) << "Route for Vehicle " << vehicle_id << ":";
|
|
int64_t route_distance{0};
|
|
int64_t route_load{0};
|
|
std::ostringstream route;
|
|
while (!routing.IsEnd(index)) {
|
|
const int node_index = manager.IndexToNode(index).value();
|
|
route_load += data.demands[node_index];
|
|
route << node_index << " Load(" << route_load << ") -> ";
|
|
const int64_t previous_index = index;
|
|
index = solution.Value(routing.NextVar(index));
|
|
route_distance += routing.GetArcCostForVehicle(previous_index, index,
|
|
int64_t{vehicle_id});
|
|
}
|
|
LOG(INFO) << route.str() << manager.IndexToNode(index).value();
|
|
LOG(INFO) << "Distance of the route: " << route_distance << "m";
|
|
LOG(INFO) << "Load of the route: " << route_load;
|
|
total_distance += route_distance;
|
|
total_load += route_load;
|
|
}
|
|
LOG(INFO) << "Total distance of all routes: " << total_distance << "m";
|
|
LOG(INFO) << "Total load of all routes: " << total_load;
|
|
LOG(INFO) << "";
|
|
LOG(INFO) << "Advanced usage:";
|
|
LOG(INFO) << "Problem solved in " << routing.solver()->wall_time() << "ms";
|
|
}
|
|
// [END solution_printer]
|
|
|
|
void VrpDropNodes() {
|
|
// 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]
|
|
|
|
// Create and register a transit callback.
|
|
// [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]
|
|
|
|
// Add Capacity constraint.
|
|
// [START capacity_constraint]
|
|
const int demand_callback_index = routing.RegisterUnaryTransitCallback(
|
|
[&data, &manager](const int64_t from_index) -> int64_t {
|
|
// Convert from routing variable Index to demand NodeIndex.
|
|
const int from_node = manager.IndexToNode(from_index).value();
|
|
return data.demands[from_node];
|
|
});
|
|
routing.AddDimensionWithVehicleCapacity(
|
|
demand_callback_index, // transit callback index
|
|
int64_t{0}, // null capacity slack
|
|
data.vehicle_capacities, // vehicle maximum capacities
|
|
true, // start cumul to zero
|
|
"Capacity");
|
|
// Allow to drop nodes.
|
|
int64_t penalty{1000};
|
|
for (int i = 1; i < data.distance_matrix.size(); ++i) {
|
|
routing.AddDisjunction(
|
|
{manager.NodeToIndex(RoutingIndexManager::NodeIndex(i))}, penalty);
|
|
}
|
|
// [END capacity_constraint]
|
|
|
|
// Setting first solution heuristic.
|
|
// [START parameters]
|
|
RoutingSearchParameters search_parameters = DefaultRoutingSearchParameters();
|
|
search_parameters.set_first_solution_strategy(
|
|
FirstSolutionStrategy::PATH_CHEAPEST_ARC);
|
|
search_parameters.set_local_search_metaheuristic(
|
|
LocalSearchMetaheuristic::GUIDED_LOCAL_SEARCH);
|
|
search_parameters.mutable_time_limit()->set_seconds(1);
|
|
// [END parameters]
|
|
|
|
// Solve the problem.
|
|
// [START solve]
|
|
const Assignment* solution = routing.SolveWithParameters(search_parameters);
|
|
// [END solve]
|
|
|
|
// Print solution on console.
|
|
// [START print_solution]
|
|
PrintSolution(data, manager, routing, *solution);
|
|
// [END print_solution]
|
|
}
|
|
} // namespace operations_research
|
|
|
|
int main(int /*argc*/, char* /*argv*/[]) {
|
|
operations_research::VrpDropNodes();
|
|
return EXIT_SUCCESS;
|
|
}
|
|
// [END program]
|