8bb54b04ef
FYI: find ortools \( -type d -name .git -prune \) -o -type f -print0 | xargs -0 sed -i 's/\(Copyright 2010\)-2018/\1-2021/g'
91 lines
3.0 KiB
Python
91 lines
3.0 KiB
Python
# Copyright 2010-2021 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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"""Vehicle Routing example."""
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# [START import]
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from ortools.constraint_solver import routing_enums_pb2
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from ortools.constraint_solver import pywrapcp
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# [END import]
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def main():
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"""Entry point of the program."""
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# Instantiate the data problem.
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# [START data]
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num_locations = 5
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num_vehicles = 1
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depot = 0
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# [END data]
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# Create the routing index manager.
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# [START index_manager]
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manager = pywrapcp.RoutingIndexManager(num_locations, 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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routing = pywrapcp.RoutingModel(manager)
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# [END routing_model]
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# Create and register a transit callback.
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# [START transit_callback]
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def distance_callback(from_index, to_index):
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"""Returns the absolute difference between the two nodes."""
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# Convert from routing variable Index to user NodeIndex.
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from_node = int(manager.IndexToNode(from_index))
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to_node = int(manager.IndexToNode(to_index))
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return abs(to_node - from_node)
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transit_callback_index = routing.RegisterTransitCallback(distance_callback)
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# [END transit_callback]
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# Define cost of each arc.
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# [START arc_cost]
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routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_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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search_parameters = pywrapcp.DefaultRoutingSearchParameters()
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search_parameters.first_solution_strategy = (
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routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC) # pylint: disable=no-member
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# [END parameters]
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# Solve the problem.
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# [START solve]
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assignment = routing.SolveWithParameters(search_parameters)
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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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print('Objective: {}'.format(assignment.ObjectiveValue()))
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index = routing.Start(0)
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plan_output = 'Route for vehicle 0:\n'
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route_distance = 0
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while not routing.IsEnd(index):
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plan_output += '{} -> '.format(manager.IndexToNode(index))
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previous_index = index
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index = assignment.Value(routing.NextVar(index))
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route_distance += routing.GetArcCostForVehicle(previous_index, index, 0)
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plan_output += '{}\n'.format(manager.IndexToNode(index))
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plan_output += 'Distance of the route: {}m\n'.format(route_distance)
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print(plan_output)
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# [END print_solution]
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if __name__ == '__main__':
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main()
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# [END program]
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