ortools-clone/examples/notebook/contrib/vendor_scheduling.ipynb

{
 "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": [
    "# vendor_scheduling"
   ]
  },
  {
   "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/contrib/vendor_scheduling.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/examples/contrib/vendor_scheduling.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": "code",
   "execution_count": null,
   "id": "code",
   "metadata": {},
   "outputs": [],
   "source": [
    "from ortools.constraint_solver import pywrapcp\n",
    "\n",
    "\n",
    "def main():\n",
    "  # Create the solver.\n",
    "  solver = pywrapcp.Solver('Vendors scheduling')\n",
    "\n",
    "  #\n",
    "  # data\n",
    "  #\n",
    "  num_vendors = 9\n",
    "  num_hours = 10\n",
    "  num_work_types = 1\n",
    "\n",
    "  trafic = [100, 500, 100, 200, 320, 300, 200, 220, 300, 120]\n",
    "  max_trafic_per_vendor = 100\n",
    "\n",
    "  # Last columns are :\n",
    "  #   index_of_the_schedule, sum of worked hours (per work type).\n",
    "  # The index is useful for branching.\n",
    "  possible_schedules = [[1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 8],\n",
    "                        [1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 4],\n",
    "                        [0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 2, 5],\n",
    "                        [0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 3, 4],\n",
    "                        [1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 4, 3],\n",
    "                        [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0]]\n",
    "\n",
    "  num_possible_schedules = len(possible_schedules)\n",
    "  selected_schedules = []\n",
    "  vendors_stat = []\n",
    "  hours_stat = []\n",
    "\n",
    "  #\n",
    "  # declare variables\n",
    "  #\n",
    "  x = {}\n",
    "\n",
    "  for i in range(num_vendors):\n",
    "    tmp = []\n",
    "    for j in range(num_hours):\n",
    "      x[i, j] = solver.IntVar(0, num_work_types, 'x[%i,%i]' % (i, j))\n",
    "      tmp.append(x[i, j])\n",
    "    selected_schedule = solver.IntVar(0, num_possible_schedules - 1,\n",
    "                                      's[%i]' % i)\n",
    "    hours = solver.IntVar(0, num_hours, 'h[%i]' % i)\n",
    "    selected_schedules.append(selected_schedule)\n",
    "    vendors_stat.append(hours)\n",
    "    tmp.append(selected_schedule)\n",
    "    tmp.append(hours)\n",
    "\n",
    "    solver.Add(solver.AllowedAssignments(tmp, possible_schedules))\n",
    "\n",
    "  #\n",
    "  # Statistics and constraints for each hour\n",
    "  #\n",
    "  for j in range(num_hours):\n",
    "    workers = solver.Sum([x[i, j] for i in range(num_vendors)]).Var()\n",
    "    hours_stat.append(workers)\n",
    "    solver.Add(workers * max_trafic_per_vendor >= trafic[j])\n",
    "\n",
    "  #\n",
    "  # Redundant constraint: sort selected_schedules\n",
    "  #\n",
    "  for i in range(num_vendors - 1):\n",
    "    solver.Add(selected_schedules[i] <= selected_schedules[i + 1])\n",
    "\n",
    "  #\n",
    "  # Search\n",
    "  #\n",
    "  db = solver.Phase(selected_schedules, solver.CHOOSE_FIRST_UNBOUND,\n",
    "                    solver.ASSIGN_MIN_VALUE)\n",
    "\n",
    "  solver.NewSearch(db)\n",
    "\n",
    "  num_solutions = 0\n",
    "  while solver.NextSolution():\n",
    "    num_solutions += 1\n",
    "\n",
    "    for i in range(num_vendors):\n",
    "      print('Vendor %i: ' % i,\n",
    "            possible_schedules[selected_schedules[i].Value()])\n",
    "    print()\n",
    "\n",
    "    print('Statistics per day:')\n",
    "    for j in range(num_hours):\n",
    "      print('Day%2i: ' % j, end=' ')\n",
    "      print(hours_stat[j].Value(), end=' ')\n",
    "      print()\n",
    "    print()\n",
    "\n",
    "  solver.EndSearch()\n",
    "  print()\n",
    "  print('num_solutions:', num_solutions)\n",
    "  print('failures:', solver.Failures())\n",
    "  print('branches:', solver.Branches())\n",
    "  print('WallTime:', solver.WallTime(), 'ms')\n",
    "\n",
    "\n",
    "main()\n",
    "\n"
   ]
  }
 ],
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