97 lines
3.1 KiB
C++
97 lines
3.1 KiB
C++
// Copyright 2010-2022 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// [START program]
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// [START import]
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#include <cmath>
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#include <cstdint>
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#include <sstream>
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#include "ortools/constraint_solver/routing.h"
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#include "ortools/constraint_solver/routing_enums.pb.h"
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#include "ortools/constraint_solver/routing_index_manager.h"
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#include "ortools/constraint_solver/routing_parameters.h"
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// [END import]
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namespace operations_research {
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void SimpleRoutingProgram() {
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// Instantiate the data problem.
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// [START data]
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int num_location = 5;
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int num_vehicles = 1;
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RoutingIndexManager::NodeIndex depot{0};
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// [END data]
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// Create Routing Index Manager
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// [START index_manager]
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RoutingIndexManager manager(num_location, num_vehicles, depot);
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// [END index_manager]
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// Create Routing Model.
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// [START routing_model]
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RoutingModel routing(manager);
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// [END routing_model]
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// Define cost of each arc.
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// [START arc_cost]
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int distance_call_index = routing.RegisterTransitCallback(
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[&manager](int64_t from_index, int64_t to_index) -> int64_t {
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// Convert from routing variable Index to user NodeIndex.
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auto from_node = manager.IndexToNode(from_index).value();
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auto to_node = manager.IndexToNode(to_index).value();
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return std::abs(to_node - from_node);
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});
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routing.SetArcCostEvaluatorOfAllVehicles(distance_call_index);
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// [END arc_cost]
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// Setting first solution heuristic.
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// [START parameters]
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RoutingSearchParameters searchParameters = DefaultRoutingSearchParameters();
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searchParameters.set_first_solution_strategy(
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FirstSolutionStrategy::PATH_CHEAPEST_ARC);
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// [END parameters]
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// Solve the problem.
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// [START solve]
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const Assignment* solution = routing.SolveWithParameters(searchParameters);
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// [END solve]
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// Print solution on console.
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// [START print_solution]
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LOG(INFO) << "Objective: " << solution->ObjectiveValue();
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// Inspect solution.
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int64_t index = routing.Start(0);
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LOG(INFO) << "Route for Vehicle 0:";
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int64_t route_distance{0};
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std::ostringstream route;
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while (routing.IsEnd(index) == false) {
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route << manager.IndexToNode(index).value() << " -> ";
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int64_t previous_index = index;
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index = solution->Value(routing.NextVar(index));
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route_distance +=
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routing.GetArcCostForVehicle(previous_index, index, int64_t{0});
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}
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LOG(INFO) << route.str() << manager.IndexToNode(index).value();
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LOG(INFO) << "Distance of the route: " << route_distance << "m";
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// [END print_solution]
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}
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} // namespace operations_research
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int main(int /*argc*/, char* /*argv*/[]) {
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operations_research::SimpleRoutingProgram();
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return EXIT_SUCCESS;
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}
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// [END program]
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