8927b03942
Some of these imports are not used. The rest of them only import string to use the string.atoi function. But string.atoi(s) on a string input is identical to just int(s). See the docs: "deprecated since 2.0".
225 lines
6.3 KiB
Python
225 lines
6.3 KiB
Python
# Copyright 2010 Hakan Kjellerstrand hakank@bonetmail.com
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
"""
|
|
|
|
Crew allocation problem in Google CP Solver.
|
|
|
|
From Gecode example crew
|
|
examples/crew.cc
|
|
'''
|
|
* Example: Airline crew allocation
|
|
*
|
|
* Assign 20 flight attendants to 10 flights. Each flight needs a certain
|
|
* number of cabin crew, and they have to speak certain languages.
|
|
* Every cabin crew member has two flights off after an attended flight.
|
|
*
|
|
'''
|
|
|
|
Compare with the following models:
|
|
* MiniZinc: http://www.hakank.org/minizinc/crew.mzn
|
|
* Comet : http://www.hakank.org/comet/crew.co
|
|
* ECLiPSe : http://hakank.org/eclipse/crew.ecl
|
|
* SICStus : http://hakank.org/sicstus/crew.pl
|
|
|
|
|
|
This model was created by Hakan Kjellerstrand (hakank@bonetmail.com)
|
|
Also see my other Google CP Solver models:
|
|
http://www.hakank.org/google_or_tools/
|
|
"""
|
|
|
|
import sys
|
|
from ortools.constraint_solver import pywrapcp
|
|
|
|
|
|
def main(sols=1):
|
|
|
|
# Create the solver.
|
|
solver = pywrapcp.Solver("Crew")
|
|
|
|
#
|
|
# data
|
|
#
|
|
names = ["Tom",
|
|
"David",
|
|
"Jeremy",
|
|
"Ron",
|
|
"Joe",
|
|
"Bill",
|
|
"Fred",
|
|
"Bob",
|
|
"Mario",
|
|
"Ed",
|
|
"Carol",
|
|
"Janet",
|
|
"Tracy",
|
|
"Marilyn",
|
|
"Carolyn",
|
|
"Cathy",
|
|
"Inez",
|
|
"Jean",
|
|
"Heather",
|
|
"Juliet"]
|
|
|
|
num_persons = len(names) # number of persons
|
|
|
|
attributes = [
|
|
# steward, hostess, french, spanish, german
|
|
[1, 0, 0, 0, 1], # Tom = 1
|
|
[1, 0, 0, 0, 0], # David = 2
|
|
[1, 0, 0, 0, 1], # Jeremy = 3
|
|
[1, 0, 0, 0, 0], # Ron = 4
|
|
[1, 0, 0, 1, 0], # Joe = 5
|
|
[1, 0, 1, 1, 0], # Bill = 6
|
|
[1, 0, 0, 1, 0], # Fred = 7
|
|
[1, 0, 0, 0, 0], # Bob = 8
|
|
[1, 0, 0, 1, 1], # Mario = 9
|
|
[1, 0, 0, 0, 0], # Ed = 10
|
|
[0, 1, 0, 0, 0], # Carol = 11
|
|
[0, 1, 0, 0, 0], # Janet = 12
|
|
[0, 1, 0, 0, 0], # Tracy = 13
|
|
[0, 1, 0, 1, 1], # Marilyn = 14
|
|
[0, 1, 0, 0, 0], # Carolyn = 15
|
|
[0, 1, 0, 0, 0], # Cathy = 16
|
|
[0, 1, 1, 1, 1], # Inez = 17
|
|
[0, 1, 1, 0, 0], # Jean = 18
|
|
[0, 1, 0, 1, 1], # Heather = 19
|
|
[0, 1, 1, 0, 0] # Juliet = 20
|
|
]
|
|
|
|
# The columns are in the following order:
|
|
# staff : Overall number of cabin crew needed
|
|
# stewards : How many stewards are required
|
|
# hostesses : How many hostesses are required
|
|
# french : How many French speaking employees are required
|
|
# spanish : How many Spanish speaking employees are required
|
|
# german : How many German speaking employees are required
|
|
required_crew = [
|
|
[4, 1, 1, 1, 1, 1], # Flight 1
|
|
[5, 1, 1, 1, 1, 1], # Flight 2
|
|
[5, 1, 1, 1, 1, 1], # ..
|
|
[6, 2, 2, 1, 1, 1],
|
|
[7, 3, 3, 1, 1, 1],
|
|
[4, 1, 1, 1, 1, 1],
|
|
[5, 1, 1, 1, 1, 1],
|
|
[6, 1, 1, 1, 1, 1],
|
|
[6, 2, 2, 1, 1, 1], # ...
|
|
[7, 3, 3, 1, 1, 1] # Flight 10
|
|
]
|
|
|
|
num_flights = len(required_crew) # number of flights
|
|
|
|
#
|
|
# declare variables
|
|
#
|
|
crew = {}
|
|
for i in range(num_flights):
|
|
for j in range(num_persons):
|
|
crew[(i, j)] = solver.IntVar(0, 1, "crew[%i,%i]" % (i, j))
|
|
crew_flat = [crew[(i, j)] for i in range(num_flights)
|
|
for j in range(num_persons)]
|
|
|
|
# number of working persons
|
|
num_working = solver.IntVar(1, num_persons, "num_working")
|
|
|
|
#
|
|
# constraints
|
|
#
|
|
|
|
# number of working persons
|
|
solver.Add(num_working == solver.Sum(
|
|
[solver.IsGreaterOrEqualCstVar(solver.Sum([crew[(f, p)]
|
|
for f in range(num_flights)]), 1)
|
|
for p in range(num_persons)]))
|
|
|
|
for f in range(num_flights):
|
|
# size of crew
|
|
tmp = [crew[(f, i)] for i in range(num_persons)]
|
|
solver.Add(solver.Sum(tmp) == required_crew[f][0])
|
|
|
|
# attributes and requirements
|
|
for j in range(5):
|
|
tmp = [attributes[i][j] * crew[(f, i)] for i in range(num_persons)]
|
|
solver.Add(solver.Sum(tmp) >= required_crew[f][j + 1])
|
|
|
|
# after a flight, break for at least two flights
|
|
for f in range(num_flights - 2):
|
|
for i in range(num_persons):
|
|
solver.Add(crew[f, i] + crew[f + 1, i] + crew[f + 2, i] <= 1)
|
|
|
|
# extra contraint: all must work at least two of the flights
|
|
# for i in range(num_persons):
|
|
# [solver.Add(solver.Sum([crew[f,i] for f in range(num_flights)]) >= 2) ]
|
|
|
|
#
|
|
# solution and search
|
|
#
|
|
solution = solver.Assignment()
|
|
solution.Add(crew_flat)
|
|
solution.Add(num_working)
|
|
|
|
db = solver.Phase(crew_flat,
|
|
solver.CHOOSE_FIRST_UNBOUND,
|
|
solver.ASSIGN_MIN_VALUE)
|
|
|
|
#
|
|
# result
|
|
#
|
|
solver.NewSearch(db)
|
|
num_solutions = 0
|
|
while solver.NextSolution():
|
|
num_solutions += 1
|
|
print "Solution #%i" % num_solutions
|
|
print "Number working:", num_working.Value()
|
|
for i in range(num_flights):
|
|
for j in range(num_persons):
|
|
print crew[i, j].Value(),
|
|
print
|
|
print
|
|
|
|
print "Flights:"
|
|
for flight in range(num_flights):
|
|
print "Flight", flight, "persons:",
|
|
for person in range(num_persons):
|
|
if crew[flight, person].Value() == 1:
|
|
print names[person],
|
|
print
|
|
print
|
|
|
|
print "Crew:"
|
|
for person in range(num_persons):
|
|
print "%-10s flights" % names[person],
|
|
for flight in range(num_flights):
|
|
if crew[flight, person].Value() == 1:
|
|
print flight,
|
|
print
|
|
print
|
|
|
|
if num_solutions >= sols:
|
|
break
|
|
solver.EndSearch()
|
|
|
|
print
|
|
print "num_solutions:", num_solutions
|
|
print "failures:", solver.Failures()
|
|
print "branches:", solver.Branches()
|
|
print "WallTime:", solver.WallTime()
|
|
|
|
num_solutions_to_show = 1
|
|
if __name__ == "__main__":
|
|
if (len(sys.argv) > 1):
|
|
num_solutions_to_show = int(sys.argv[1])
|
|
|
|
main(num_solutions_to_show)
|