191 lines
6.9 KiB
Plaintext
191 lines
6.9 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"##### Copyright 2020 Google LLC."
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Licensed under the Apache License, Version 2.0 (the \"License\");\n",
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"you may not use this file except in compliance with the License.\n",
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"You may obtain a copy of the License at\n",
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"\n",
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" http://www.apache.org/licenses/LICENSE-2.0\n",
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"\n",
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"Unless required by applicable law or agreed to in writing, software\n",
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"distributed under the License is distributed on an \"AS IS\" BASIS,\n",
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"WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n",
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"See the License for the specific language governing permissions and\n",
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"limitations under the License.\n"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# vrp_with_time_limit"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"<table align=\"left\">\n",
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"<td>\n",
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"<a href=\"https://colab.research.google.com/github/google/or-tools/blob/master/examples/notebook/constraint_solver/vrp_with_time_limit.ipynb\"><img src=\"https://raw.githubusercontent.com/google/or-tools/master/tools/colab_32px.png\"/>Run in Google Colab</a>\n",
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"</td>\n",
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"<td>\n",
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"<a href=\"https://github.com/google/or-tools/blob/master/ortools/constraint_solver/samples/vrp_with_time_limit.py\"><img src=\"https://raw.githubusercontent.com/google/or-tools/master/tools/github_32px.png\"/>View source on GitHub</a>\n",
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"</td>\n",
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"</table>"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"First, you must install [ortools](https://pypi.org/project/ortools/) package in this colab."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"!pip install ortools"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# Copyright 2010-2018 Google LLC\n",
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"# Licensed under the Apache License, Version 2.0 (the \"License\");\n",
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"# you may not use this file except in compliance with the License.\n",
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"# You may obtain a copy of the License at\n",
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"#\n",
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"# http://www.apache.org/licenses/LICENSE-2.0\n",
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"#\n",
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"# Unless required by applicable law or agreed to in writing, software\n",
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"# distributed under the License is distributed on an \"AS IS\" BASIS,\n",
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"# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n",
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"# See the License for the specific language governing permissions and\n",
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"# limitations under the License.\n",
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"# [START program]\n",
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"\"\"\"Vehicles Routing Problem (VRP).\"\"\"\n",
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"\n",
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"# [START import]\n",
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"from ortools.constraint_solver import routing_enums_pb2\n",
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"from ortools.constraint_solver import pywrapcp\n",
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"# [END import]\n",
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"\n",
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"# [START solution_printer]\n",
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"def print_solution(manager, routing, solution):\n",
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" \"\"\"Prints solution on console.\"\"\"\n",
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" max_route_distance = 0\n",
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" for vehicle_id in range(manager.GetNumberOfVehicles()):\n",
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" index = routing.Start(vehicle_id)\n",
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" plan_output = 'Route for vehicle {}:\\n'.format(vehicle_id)\n",
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" route_distance = 0\n",
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" while not routing.IsEnd(index):\n",
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" plan_output += ' {} -> '.format(manager.IndexToNode(index))\n",
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" previous_index = index\n",
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" index = solution.Value(routing.NextVar(index))\n",
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" route_distance += routing.GetArcCostForVehicle(\n",
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" previous_index, index, vehicle_id)\n",
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" plan_output += '{}\\n'.format(manager.IndexToNode(index))\n",
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" plan_output += 'Distance of the route: {}m\\n'.format(route_distance)\n",
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" print(plan_output)\n",
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" max_route_distance = max(route_distance, max_route_distance)\n",
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" print('Maximum of the route distances: {}m'.format(max_route_distance))\n",
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"# [END solution_printer]\n",
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"\n",
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"\n",
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"\"\"\"Solve the CVRP problem.\"\"\"\n",
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"# Instantiate the data problem.\n",
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"# [START data]\n",
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"num_locations = 20;\n",
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"num_vehicles = 5;\n",
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"depot = 0;\n",
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"# [END data]\n",
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"\n",
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"# Create the routing index manager.\n",
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"# [START index_manager]\n",
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"manager = pywrapcp.RoutingIndexManager(\n",
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" num_locations, num_vehicles, depot)\n",
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"# [END index_manager]\n",
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"\n",
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"# Create Routing Model.\n",
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"# [START routing_model]\n",
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"routing = pywrapcp.RoutingModel(manager)\n",
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"\n",
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"# [END routing_model]\n",
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"\n",
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"# Create and register a transit callback.\n",
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"# [START transit_callback]\n",
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"def distance_callback(from_index, to_index):\n",
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" \"\"\"Returns the distance between the two nodes.\"\"\"\n",
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" # Convert from routing variable Index to distance matrix NodeIndex.\n",
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" from_node = manager.IndexToNode(from_index)\n",
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" to_node = manager.IndexToNode(to_index)\n",
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" return 1\n",
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"\n",
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"transit_callback_index = routing.RegisterTransitCallback(distance_callback)\n",
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"# [END transit_callback]\n",
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"\n",
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"# Define cost of each arc.\n",
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"# [START arc_cost]\n",
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"routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index)\n",
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"# [END arc_cost]\n",
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"\n",
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"# Add Distance constraint.\n",
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"# [START distance_constraint]\n",
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"dimension_name = 'Distance'\n",
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"routing.AddDimension(\n",
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" transit_callback_index,\n",
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" 0, # no slack\n",
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" 3000, # vehicle maximum travel distance\n",
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" True, # start cumul to zero\n",
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" dimension_name)\n",
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"distance_dimension = routing.GetDimensionOrDie(dimension_name)\n",
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"distance_dimension.SetGlobalSpanCostCoefficient(100)\n",
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"# [END distance_constraint]\n",
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"\n",
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"# Setting first solution heuristic.\n",
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"# [START parameters]\n",
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"search_parameters = pywrapcp.DefaultRoutingSearchParameters()\n",
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"search_parameters.first_solution_strategy = (\n",
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" routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC)\n",
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"search_parameters.local_search_metaheuristic = (\n",
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" routing_enums_pb2.LocalSearchMetaheuristic.GUIDED_LOCAL_SEARCH)\n",
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"search_parameters.log_search = True\n",
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"search_parameters.time_limit.FromSeconds(10)\n",
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"# [END parameters]\n",
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"\n",
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"# Solve the problem.\n",
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"# [START solve]\n",
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"solution = routing.SolveWithParameters(search_parameters)\n",
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"# [END solve]\n",
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"\n",
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"# Print solution on console.\n",
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"# [START print_solution]\n",
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"if solution:\n",
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" print_solution(manager, routing, solution)\n",
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"# [END print_solution]\n",
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"\n"
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]
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}
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],
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"metadata": {},
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"nbformat": 4,
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"nbformat_minor": 4
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}
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