239 lines
9.6 KiB
Plaintext
239 lines
9.6 KiB
Plaintext
{
|
|
"cells": [
|
|
{
|
|
"cell_type": "markdown",
|
|
"id": "google",
|
|
"metadata": {},
|
|
"source": [
|
|
"##### Copyright 2025 Google LLC."
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"id": "apache",
|
|
"metadata": {},
|
|
"source": [
|
|
"Licensed under the Apache License, Version 2.0 (the \"License\");\n",
|
|
"you may not use this file except in compliance with the License.\n",
|
|
"You may obtain a copy of the License at\n",
|
|
"\n",
|
|
" http://www.apache.org/licenses/LICENSE-2.0\n",
|
|
"\n",
|
|
"Unless required by applicable law or agreed to in writing, software\n",
|
|
"distributed under the License is distributed on an \"AS IS\" BASIS,\n",
|
|
"WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n",
|
|
"See the License for the specific language governing permissions and\n",
|
|
"limitations under the License.\n"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"id": "basename",
|
|
"metadata": {},
|
|
"source": [
|
|
"# vrp_drop_nodes"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"id": "link",
|
|
"metadata": {},
|
|
"source": [
|
|
"<table align=\"left\">\n",
|
|
"<td>\n",
|
|
"<a href=\"https://colab.research.google.com/github/google/or-tools/blob/main/examples/notebook/constraint_solver/vrp_drop_nodes.ipynb\"><img src=\"https://raw.githubusercontent.com/google/or-tools/main/tools/colab_32px.png\"/>Run in Google Colab</a>\n",
|
|
"</td>\n",
|
|
"<td>\n",
|
|
"<a href=\"https://github.com/google/or-tools/blob/main/ortools/constraint_solver/samples/vrp_drop_nodes.py\"><img src=\"https://raw.githubusercontent.com/google/or-tools/main/tools/github_32px.png\"/>View source on GitHub</a>\n",
|
|
"</td>\n",
|
|
"</table>"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"id": "doc",
|
|
"metadata": {},
|
|
"source": [
|
|
"First, you must install [ortools](https://pypi.org/project/ortools/) package in this colab."
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": null,
|
|
"id": "install",
|
|
"metadata": {},
|
|
"outputs": [],
|
|
"source": [
|
|
"%pip install ortools"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "markdown",
|
|
"id": "description",
|
|
"metadata": {},
|
|
"source": [
|
|
"\n",
|
|
"Capacited Vehicles Routing Problem (CVRP).\n"
|
|
]
|
|
},
|
|
{
|
|
"cell_type": "code",
|
|
"execution_count": null,
|
|
"id": "code",
|
|
"metadata": {},
|
|
"outputs": [],
|
|
"source": [
|
|
"from ortools.constraint_solver import routing_enums_pb2\n",
|
|
"from ortools.constraint_solver import pywrapcp\n",
|
|
"\n",
|
|
"\n",
|
|
"\n",
|
|
"def create_data_model():\n",
|
|
" \"\"\"Stores the data for the problem.\"\"\"\n",
|
|
" data = {}\n",
|
|
" data[\"distance_matrix\"] = [\n",
|
|
" # fmt: off\n",
|
|
" [0, 548, 776, 696, 582, 274, 502, 194, 308, 194, 536, 502, 388, 354, 468, 776, 662],\n",
|
|
" [548, 0, 684, 308, 194, 502, 730, 354, 696, 742, 1084, 594, 480, 674, 1016, 868, 1210],\n",
|
|
" [776, 684, 0, 992, 878, 502, 274, 810, 468, 742, 400, 1278, 1164, 1130, 788, 1552, 754],\n",
|
|
" [696, 308, 992, 0, 114, 650, 878, 502, 844, 890, 1232, 514, 628, 822, 1164, 560, 1358],\n",
|
|
" [582, 194, 878, 114, 0, 536, 764, 388, 730, 776, 1118, 400, 514, 708, 1050, 674, 1244],\n",
|
|
" [274, 502, 502, 650, 536, 0, 228, 308, 194, 240, 582, 776, 662, 628, 514, 1050, 708],\n",
|
|
" [502, 730, 274, 878, 764, 228, 0, 536, 194, 468, 354, 1004, 890, 856, 514, 1278, 480],\n",
|
|
" [194, 354, 810, 502, 388, 308, 536, 0, 342, 388, 730, 468, 354, 320, 662, 742, 856],\n",
|
|
" [308, 696, 468, 844, 730, 194, 194, 342, 0, 274, 388, 810, 696, 662, 320, 1084, 514],\n",
|
|
" [194, 742, 742, 890, 776, 240, 468, 388, 274, 0, 342, 536, 422, 388, 274, 810, 468],\n",
|
|
" [536, 1084, 400, 1232, 1118, 582, 354, 730, 388, 342, 0, 878, 764, 730, 388, 1152, 354],\n",
|
|
" [502, 594, 1278, 514, 400, 776, 1004, 468, 810, 536, 878, 0, 114, 308, 650, 274, 844],\n",
|
|
" [388, 480, 1164, 628, 514, 662, 890, 354, 696, 422, 764, 114, 0, 194, 536, 388, 730],\n",
|
|
" [354, 674, 1130, 822, 708, 628, 856, 320, 662, 388, 730, 308, 194, 0, 342, 422, 536],\n",
|
|
" [468, 1016, 788, 1164, 1050, 514, 514, 662, 320, 274, 388, 650, 536, 342, 0, 764, 194],\n",
|
|
" [776, 868, 1552, 560, 674, 1050, 1278, 742, 1084, 810, 1152, 274, 388, 422, 764, 0, 798],\n",
|
|
" [662, 1210, 754, 1358, 1244, 708, 480, 856, 514, 468, 354, 844, 730, 536, 194, 798, 0],\n",
|
|
" # fmt: on\n",
|
|
" ]\n",
|
|
" data[\"demands\"] = [0, 1, 1, 3, 6, 3, 6, 8, 8, 1, 2, 1, 2, 6, 6, 8, 8]\n",
|
|
" data[\"vehicle_capacities\"] = [15, 15, 15, 15]\n",
|
|
" data[\"num_vehicles\"] = 4\n",
|
|
" data[\"depot\"] = 0\n",
|
|
" return data\n",
|
|
"\n",
|
|
"\n",
|
|
"def print_solution(data, manager, routing, assignment):\n",
|
|
" \"\"\"Prints assignment on console.\"\"\"\n",
|
|
" print(f\"Objective: {assignment.ObjectiveValue()}\")\n",
|
|
" # Display dropped nodes.\n",
|
|
" dropped_nodes = \"Dropped nodes:\"\n",
|
|
" for node in range(routing.Size()):\n",
|
|
" if routing.IsStart(node) or routing.IsEnd(node):\n",
|
|
" continue\n",
|
|
" if assignment.Value(routing.NextVar(node)) == node:\n",
|
|
" dropped_nodes += f\" {manager.IndexToNode(node)}\"\n",
|
|
" print(dropped_nodes)\n",
|
|
" # Display routes\n",
|
|
" total_distance = 0\n",
|
|
" total_load = 0\n",
|
|
" for vehicle_id in range(data[\"num_vehicles\"]):\n",
|
|
" if not routing.IsVehicleUsed(assignment, vehicle_id):\n",
|
|
" continue\n",
|
|
" index = routing.Start(vehicle_id)\n",
|
|
" plan_output = f\"Route for vehicle {vehicle_id}:\\n\"\n",
|
|
" route_distance = 0\n",
|
|
" route_load = 0\n",
|
|
" while not routing.IsEnd(index):\n",
|
|
" node_index = manager.IndexToNode(index)\n",
|
|
" route_load += data[\"demands\"][node_index]\n",
|
|
" plan_output += f\" {node_index} Load({route_load}) -> \"\n",
|
|
" previous_index = index\n",
|
|
" index = assignment.Value(routing.NextVar(index))\n",
|
|
" route_distance += routing.GetArcCostForVehicle(\n",
|
|
" previous_index, index, vehicle_id\n",
|
|
" )\n",
|
|
" plan_output += f\" {manager.IndexToNode(index)} Load({route_load})\\n\"\n",
|
|
" plan_output += f\"Distance of the route: {route_distance}m\\n\"\n",
|
|
" plan_output += f\"Load of the route: {route_load}\\n\"\n",
|
|
" print(plan_output)\n",
|
|
" total_distance += route_distance\n",
|
|
" total_load += route_load\n",
|
|
" print(f\"Total Distance of all routes: {total_distance}m\")\n",
|
|
" print(f\"Total Load of all routes: {total_load}\")\n",
|
|
"\n",
|
|
"\n",
|
|
"def main():\n",
|
|
" \"\"\"Solve the CVRP problem.\"\"\"\n",
|
|
" # Instantiate the data problem.\n",
|
|
" data = create_data_model()\n",
|
|
"\n",
|
|
" # Create the routing index manager.\n",
|
|
" manager = pywrapcp.RoutingIndexManager(\n",
|
|
" len(data[\"distance_matrix\"]), data[\"num_vehicles\"], data[\"depot\"]\n",
|
|
" )\n",
|
|
"\n",
|
|
" # Create Routing Model.\n",
|
|
" routing = pywrapcp.RoutingModel(manager)\n",
|
|
"\n",
|
|
" # Create and register a transit callback.\n",
|
|
" def distance_callback(from_index, to_index):\n",
|
|
" \"\"\"Returns the distance between the two nodes.\"\"\"\n",
|
|
" # Convert from routing variable Index to distance matrix NodeIndex.\n",
|
|
" from_node = manager.IndexToNode(from_index)\n",
|
|
" to_node = manager.IndexToNode(to_index)\n",
|
|
" return data[\"distance_matrix\"][from_node][to_node]\n",
|
|
"\n",
|
|
" transit_callback_index = routing.RegisterTransitCallback(distance_callback)\n",
|
|
"\n",
|
|
" # Define cost of each arc.\n",
|
|
" routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index)\n",
|
|
"\n",
|
|
" # Add Capacity constraint.\n",
|
|
" def demand_callback(from_index):\n",
|
|
" \"\"\"Returns the demand of the node.\"\"\"\n",
|
|
" # Convert from routing variable Index to demands NodeIndex.\n",
|
|
" from_node = manager.IndexToNode(from_index)\n",
|
|
" return data[\"demands\"][from_node]\n",
|
|
"\n",
|
|
" demand_callback_index = routing.RegisterUnaryTransitCallback(demand_callback)\n",
|
|
" routing.AddDimensionWithVehicleCapacity(\n",
|
|
" demand_callback_index,\n",
|
|
" 0, # null capacity slack\n",
|
|
" data[\"vehicle_capacities\"], # vehicle maximum capacities\n",
|
|
" True, # start cumul to zero\n",
|
|
" \"Capacity\",\n",
|
|
" )\n",
|
|
" # Allow to drop nodes.\n",
|
|
" penalty = 1000\n",
|
|
" for node in range(1, len(data[\"distance_matrix\"])):\n",
|
|
" routing.AddDisjunction([manager.NodeToIndex(node)], penalty)\n",
|
|
"\n",
|
|
" # Setting first solution heuristic.\n",
|
|
" search_parameters = pywrapcp.DefaultRoutingSearchParameters()\n",
|
|
" search_parameters.first_solution_strategy = (\n",
|
|
" routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC\n",
|
|
" )\n",
|
|
" search_parameters.local_search_metaheuristic = (\n",
|
|
" routing_enums_pb2.LocalSearchMetaheuristic.GUIDED_LOCAL_SEARCH\n",
|
|
" )\n",
|
|
" search_parameters.time_limit.FromSeconds(1)\n",
|
|
"\n",
|
|
" # Solve the problem.\n",
|
|
" assignment = routing.SolveWithParameters(search_parameters)\n",
|
|
"\n",
|
|
" # Print solution on console.\n",
|
|
" if assignment:\n",
|
|
" print_solution(data, manager, routing, assignment)\n",
|
|
"\n",
|
|
"\n",
|
|
"main()\n",
|
|
"\n"
|
|
]
|
|
}
|
|
],
|
|
"metadata": {
|
|
"language_info": {
|
|
"name": "python"
|
|
}
|
|
},
|
|
"nbformat": 4,
|
|
"nbformat_minor": 5
|
|
}
|