280 lines
9.5 KiB
Plaintext
280 lines
9.5 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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"# crew"
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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/contrib/crew.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/examples/contrib/crew.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 Hakan Kjellerstrand hakank@gmail.com\n",
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"#\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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"\"\"\"\n",
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"\n",
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" Crew allocation problem in Google CP Solver.\n",
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"\n",
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" From Gecode example crew\n",
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" examples/crew.cc\n",
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" '''\n",
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" * Example: Airline crew allocation\n",
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" *\n",
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" * Assign 20 flight attendants to 10 flights. Each flight needs a certain\n",
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" * number of cabin crew, and they have to speak certain languages.\n",
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" * Every cabin crew member has two flights off after an attended flight.\n",
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" *\n",
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" '''\n",
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"\n",
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" Compare with the following models:\n",
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" * MiniZinc: http://www.hakank.org/minizinc/crew.mzn\n",
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" * Comet : http://www.hakank.org/comet/crew.co\n",
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" * ECLiPSe : http://hakank.org/eclipse/crew.ecl\n",
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" * SICStus : http://hakank.org/sicstus/crew.pl\n",
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"\n",
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"\n",
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" This model was created by Hakan Kjellerstrand (hakank@gmail.com)\n",
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" Also see my other Google CP Solver models:\n",
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" http://www.hakank.org/google_or_tools/\n",
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"\"\"\"\n",
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"import sys\n",
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"from ortools.constraint_solver import pywrapcp\n",
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"\n",
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"\n",
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"\n",
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"# Create the solver.\n",
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"solver = pywrapcp.Solver(\"Crew\")\n",
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"\n",
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"#\n",
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"# data\n",
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"#\n",
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"names = [\n",
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" \"Tom\", \"David\", \"Jeremy\", \"Ron\", \"Joe\", \"Bill\", \"Fred\", \"Bob\", \"Mario\",\n",
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" \"Ed\", \"Carol\", \"Janet\", \"Tracy\", \"Marilyn\", \"Carolyn\", \"Cathy\", \"Inez\",\n",
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" \"Jean\", \"Heather\", \"Juliet\"\n",
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"]\n",
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"\n",
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"num_persons = len(names) # number of persons\n",
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"\n",
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"attributes = [\n",
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" # steward, hostess, french, spanish, german\n",
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" [1, 0, 0, 0, 1], # Tom = 1\n",
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" [1, 0, 0, 0, 0], # David = 2\n",
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" [1, 0, 0, 0, 1], # Jeremy = 3\n",
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" [1, 0, 0, 0, 0], # Ron = 4\n",
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" [1, 0, 0, 1, 0], # Joe = 5\n",
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" [1, 0, 1, 1, 0], # Bill = 6\n",
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" [1, 0, 0, 1, 0], # Fred = 7\n",
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" [1, 0, 0, 0, 0], # Bob = 8\n",
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" [1, 0, 0, 1, 1], # Mario = 9\n",
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" [1, 0, 0, 0, 0], # Ed = 10\n",
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" [0, 1, 0, 0, 0], # Carol = 11\n",
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" [0, 1, 0, 0, 0], # Janet = 12\n",
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" [0, 1, 0, 0, 0], # Tracy = 13\n",
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" [0, 1, 0, 1, 1], # Marilyn = 14\n",
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" [0, 1, 0, 0, 0], # Carolyn = 15\n",
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" [0, 1, 0, 0, 0], # Cathy = 16\n",
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" [0, 1, 1, 1, 1], # Inez = 17\n",
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" [0, 1, 1, 0, 0], # Jean = 18\n",
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" [0, 1, 0, 1, 1], # Heather = 19\n",
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" [0, 1, 1, 0, 0] # Juliet = 20\n",
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"]\n",
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"\n",
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"# The columns are in the following order:\n",
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"# staff : Overall number of cabin crew needed\n",
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"# stewards : How many stewards are required\n",
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"# hostesses : How many hostesses are required\n",
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"# french : How many French speaking employees are required\n",
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"# spanish : How many Spanish speaking employees are required\n",
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"# german : How many German speaking employees are required\n",
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"required_crew = [\n",
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" [4, 1, 1, 1, 1, 1], # Flight 1\n",
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" [5, 1, 1, 1, 1, 1], # Flight 2\n",
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" [5, 1, 1, 1, 1, 1], # ..\n",
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" [6, 2, 2, 1, 1, 1],\n",
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" [7, 3, 3, 1, 1, 1],\n",
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" [4, 1, 1, 1, 1, 1],\n",
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" [5, 1, 1, 1, 1, 1],\n",
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" [6, 1, 1, 1, 1, 1],\n",
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" [6, 2, 2, 1, 1, 1], # ...\n",
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" [7, 3, 3, 1, 1, 1] # Flight 10\n",
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"]\n",
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"\n",
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"num_flights = len(required_crew) # number of flights\n",
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"\n",
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"#\n",
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"# declare variables\n",
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"#\n",
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"crew = {}\n",
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"for i in range(num_flights):\n",
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" for j in range(num_persons):\n",
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" crew[(i, j)] = solver.IntVar(0, 1, \"crew[%i,%i]\" % (i, j))\n",
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"crew_flat = [\n",
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" crew[(i, j)] for i in range(num_flights) for j in range(num_persons)\n",
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"]\n",
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"\n",
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"# number of working persons\n",
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"num_working = solver.IntVar(1, num_persons, \"num_working\")\n",
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"\n",
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"#\n",
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"# constraints\n",
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"#\n",
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"\n",
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"# number of working persons\n",
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"solver.Add(num_working == solver.Sum([\n",
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" solver.IsGreaterOrEqualCstVar(\n",
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" solver.Sum([crew[(f, p)]\n",
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" for f in range(num_flights)]), 1)\n",
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" for p in range(num_persons)\n",
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"]))\n",
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"\n",
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"for f in range(num_flights):\n",
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" # size of crew\n",
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" tmp = [crew[(f, i)] for i in range(num_persons)]\n",
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" solver.Add(solver.Sum(tmp) == required_crew[f][0])\n",
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"\n",
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" # attributes and requirements\n",
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" for j in range(5):\n",
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" tmp = [attributes[i][j] * crew[(f, i)] for i in range(num_persons)]\n",
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" solver.Add(solver.Sum(tmp) >= required_crew[f][j + 1])\n",
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"\n",
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"# after a flight, break for at least two flights\n",
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"for f in range(num_flights - 2):\n",
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" for i in range(num_persons):\n",
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" solver.Add(crew[f, i] + crew[f + 1, i] + crew[f + 2, i] <= 1)\n",
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"\n",
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"# extra contraint: all must work at least two of the flights\n",
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"# for i in range(num_persons):\n",
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"# [solver.Add(solver.Sum([crew[f,i] for f in range(num_flights)]) >= 2) ]\n",
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"\n",
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"#\n",
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"# solution and search\n",
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"#\n",
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"solution = solver.Assignment()\n",
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"solution.Add(crew_flat)\n",
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"solution.Add(num_working)\n",
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"\n",
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"db = solver.Phase(crew_flat, solver.CHOOSE_FIRST_UNBOUND,\n",
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" solver.ASSIGN_MIN_VALUE)\n",
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"\n",
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"#\n",
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"# result\n",
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"#\n",
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"solver.NewSearch(db)\n",
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"num_solutions = 0\n",
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"while solver.NextSolution():\n",
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" num_solutions += 1\n",
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" print(\"Solution #%i\" % num_solutions)\n",
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" print(\"Number working:\", num_working.Value())\n",
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" for i in range(num_flights):\n",
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" for j in range(num_persons):\n",
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" print(crew[i, j].Value(), end=\" \")\n",
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" print()\n",
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" print()\n",
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"\n",
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" print(\"Flights:\")\n",
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" for flight in range(num_flights):\n",
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" print(\"Flight\", flight, \"persons:\", end=\" \")\n",
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" for person in range(num_persons):\n",
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" if crew[flight, person].Value() == 1:\n",
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" print(names[person], end=\" \")\n",
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" print()\n",
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" print()\n",
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"\n",
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" print(\"Crew:\")\n",
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" for person in range(num_persons):\n",
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" print(\"%-10s flights\" % names[person], end=\" \")\n",
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" for flight in range(num_flights):\n",
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" if crew[flight, person].Value() == 1:\n",
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" print(flight, end=\" \")\n",
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" print()\n",
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" print()\n",
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"\n",
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" if num_solutions >= sols:\n",
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" break\n",
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"solver.EndSearch()\n",
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"\n",
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"print()\n",
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"print(\"num_solutions:\", num_solutions)\n",
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"print(\"failures:\", solver.Failures())\n",
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"print(\"branches:\", solver.Branches())\n",
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"print(\"WallTime:\", solver.WallTime())\n",
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"\n",
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"num_solutions_to_show = 1\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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