ortools-clone/examples/notebook/constraint_solver/simple_routing_program.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "58e307f8",
   "metadata": {},
   "source": [
    "##### Copyright 2021 Google LLC."
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e54fadbd",
   "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": "6231fc22",
   "metadata": {},
   "source": [
    "# simple_routing_program"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "53c76b90",
   "metadata": {},
   "source": [
    "<table align=\"left\">\n",
    "<td>\n",
    "<a href=\"https://colab.research.google.com/github/google/or-tools/blob/master/examples/notebook/constraint_solver/simple_routing_program.ipynb\"><img src=\"https://raw.githubusercontent.com/google/or-tools/master/tools/colab_32px.png\"/>Run in Google Colab</a>\n",
    "</td>\n",
    "<td>\n",
    "<a href=\"https://github.com/google/or-tools/blob/master/ortools/constraint_solver/samples/simple_routing_program.py\"><img src=\"https://raw.githubusercontent.com/google/or-tools/master/tools/github_32px.png\"/>View source on GitHub</a>\n",
    "</td>\n",
    "</table>"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "14872edb",
   "metadata": {},
   "source": [
    "First, you must install [ortools](https://pypi.org/project/ortools/) package in this colab."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "5ce7a297",
   "metadata": {},
   "outputs": [],
   "source": [
    "!pip install ortools"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "d34ffa99",
   "metadata": {},
   "outputs": [],
   "source": [
    "#!/usr/bin/env python3\n",
    "# Copyright 2010-2021 Google LLC\n",
    "# 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",
    "# [START program]\n",
    "\"\"\"Vehicle Routing example.\"\"\"\n",
    "\n",
    "# [START import]\n",
    "from ortools.constraint_solver import routing_enums_pb2\n",
    "from ortools.constraint_solver import pywrapcp\n",
    "# [END import]\n",
    "\n",
    "\n",
    "\"\"\"Entry point of the program.\"\"\"\n",
    "# Instantiate the data problem.\n",
    "# [START data]\n",
    "num_locations = 5\n",
    "num_vehicles = 1\n",
    "depot = 0\n",
    "# [END data]\n",
    "\n",
    "# Create the routing index manager.\n",
    "# [START index_manager]\n",
    "manager = pywrapcp.RoutingIndexManager(num_locations, num_vehicles, depot)\n",
    "# [END index_manager]\n",
    "\n",
    "# Create Routing Model.\n",
    "# [START routing_model]\n",
    "routing = pywrapcp.RoutingModel(manager)\n",
    "\n",
    "# [END routing_model]\n",
    "\n",
    "# Create and register a transit callback.\n",
    "# [START transit_callback]\n",
    "def distance_callback(from_index, to_index):\n",
    "    \"\"\"Returns the absolute difference between the two nodes.\"\"\"\n",
    "    # Convert from routing variable Index to user NodeIndex.\n",
    "    from_node = int(manager.IndexToNode(from_index))\n",
    "    to_node = int(manager.IndexToNode(to_index))\n",
    "    return abs(to_node - from_node)\n",
    "\n",
    "transit_callback_index = routing.RegisterTransitCallback(distance_callback)\n",
    "# [END transit_callback]\n",
    "\n",
    "# Define cost of each arc.\n",
    "# [START arc_cost]\n",
    "routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index)\n",
    "# [END arc_cost]\n",
    "\n",
    "# Setting first solution heuristic.\n",
    "# [START parameters]\n",
    "search_parameters = pywrapcp.DefaultRoutingSearchParameters()\n",
    "search_parameters.first_solution_strategy = (\n",
    "    routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC)  # pylint: disable=no-member\n",
    "# [END parameters]\n",
    "\n",
    "# Solve the problem.\n",
    "# [START solve]\n",
    "assignment = routing.SolveWithParameters(search_parameters)\n",
    "# [END solve]\n",
    "\n",
    "# Print solution on console.\n",
    "# [START print_solution]\n",
    "print('Objective: {}'.format(assignment.ObjectiveValue()))\n",
    "index = routing.Start(0)\n",
    "plan_output = 'Route for vehicle 0:\\n'\n",
    "route_distance = 0\n",
    "while not routing.IsEnd(index):\n",
    "    plan_output += '{} -> '.format(manager.IndexToNode(index))\n",
    "    previous_index = index\n",
    "    index = assignment.Value(routing.NextVar(index))\n",
    "    route_distance += routing.GetArcCostForVehicle(previous_index, index, 0)\n",
    "plan_output += '{}\\n'.format(manager.IndexToNode(index))\n",
    "plan_output += 'Distance of the route: {}m\\n'.format(route_distance)\n",
    "print(plan_output)\n",
    "# [END print_solution]\n",
    "\n"
   ]
  }
 ],
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