Merge pull request #692 from turadg/patch-1
port wedding_optimal_chart.cs to Python
This commit is contained in:
lperron
179
examples/python/wedding_optimal_chart.py
Normal file
179
examples/python/wedding_optimal_chart.py
Normal file
@@ -0,0 +1,179 @@
|
||||
#
|
||||
# Copyright 2018 Turadg Aleahmad
|
||||
#
|
||||
# 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.
|
||||
|
||||
from __future__ import print_function
|
||||
from ortools.constraint_solver import pywrapcp
|
||||
from ortools.constraint_solver import solver_parameters_pb2
|
||||
|
||||
|
||||
"""
|
||||
Finding an optimal wedding seating chart.
|
||||
|
||||
From
|
||||
Meghan L. Bellows and J. D. Luc Peterson
|
||||
"Finding an optimal seating chart for a wedding"
|
||||
http://www.improbable.com/news/2012/Optimal-seating-chart.pdf
|
||||
http://www.improbable.com/2012/02/12/finding-an-optimal-seating-chart-for-a-wedding
|
||||
|
||||
Every year, millions of brides (not to mention their mothers, future
|
||||
mothers-in-law, and occasionally grooms) struggle with one of the
|
||||
most daunting tasks during the wedding-planning process: the
|
||||
seating chart. The guest responses are in, banquet hall is booked,
|
||||
menu choices have been made. You think the hard parts are over,
|
||||
but you have yet to embark upon the biggest headache of them all.
|
||||
In order to make this process easier, we present a mathematical
|
||||
formulation that models the seating chart problem. This model can
|
||||
be solved to find the optimal arrangement of guests at tables.
|
||||
At the very least, it can provide a starting point and hopefully
|
||||
minimize stress and arguments…
|
||||
|
||||
Adapted from https://github.com/google/or-tools/blob/master/examples/csharp/wedding_optimal_chart.cs
|
||||
"""
|
||||
def main():
|
||||
# Instantiate a CP solver.
|
||||
parameters = pywrapcp.Solver.DefaultSolverParameters()
|
||||
solver = pywrapcp.Solver("WeddingOptimalChart", parameters)
|
||||
|
||||
#
|
||||
# Data
|
||||
#
|
||||
|
||||
# Easy problem (from the paper)
|
||||
n = 2 # number of tables
|
||||
a = 10 # maximum number of guests a table can seat
|
||||
b = 1 # minimum number of people each guest knows at their table
|
||||
|
||||
# Slightly harder problem (also from the paper)
|
||||
# n = 5 # number of tables
|
||||
# a = 4 # maximum number of guests a table can seat
|
||||
# b = 1 # minimum number of people each guest knows at their table
|
||||
|
||||
# Connection matrix: who knows who, and how strong
|
||||
# is the relation
|
||||
C = [
|
||||
[ 1,50, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[50, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 1, 1, 1,50, 1, 1, 1, 1,10, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 1, 1,50, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 1, 1, 1, 1, 1,50, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 1, 1, 1, 1,50, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 1, 1, 1, 1, 1, 1, 1,50, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 1, 1, 1, 1, 1, 1,50, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 1, 1,10, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,50, 1, 1, 1, 1, 1, 1],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0,50, 1, 1, 1, 1, 1, 1, 1],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1],
|
||||
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1]
|
||||
]
|
||||
|
||||
# Names of the guests. B: Bride side, G: Groom side
|
||||
names = [
|
||||
"Deb (B)",
|
||||
"John (B)",
|
||||
"Martha (B)",
|
||||
"Travis (B)",
|
||||
"Allan (B)",
|
||||
"Lois (B)",
|
||||
"Jayne (B)",
|
||||
"Brad (B)",
|
||||
"Abby (B)",
|
||||
"Mary Helen (G)",
|
||||
"Lee (G)",
|
||||
"Annika (G)",
|
||||
"Carl (G)",
|
||||
"Colin (G)",
|
||||
"Shirley (G)",
|
||||
"DeAnn (G)",
|
||||
"Lori (G)"
|
||||
]
|
||||
|
||||
m = len(C)
|
||||
|
||||
NRANGE = range(n)
|
||||
MRANGE = range(m)
|
||||
|
||||
#
|
||||
# Decision variables
|
||||
#
|
||||
tables = [solver.IntVar(0, n-1, 'x[%i]' % i) for i in MRANGE]
|
||||
|
||||
z = solver.Sum([ C[j][k] * (tables[j] == tables[k])
|
||||
for j in MRANGE
|
||||
for k in MRANGE if j < k])
|
||||
|
||||
#
|
||||
# Constraints
|
||||
#
|
||||
for i in NRANGE:
|
||||
minGuests = [
|
||||
(tables[j] == i) * (tables[k] == i)
|
||||
for j in MRANGE
|
||||
for k in MRANGE if j < k and C[j][k] > 0
|
||||
]
|
||||
solver.Add(solver.Sum(minGuests) >= b);
|
||||
|
||||
maxGuests = [tables[j] == i for j in MRANGE]
|
||||
solver.Add(solver.Sum(maxGuests) <= a);
|
||||
|
||||
# Symmetry breaking
|
||||
solver.Add(tables[0] == 0)
|
||||
|
||||
#
|
||||
# Objective
|
||||
#
|
||||
objective = solver.Maximize(z, 1)
|
||||
|
||||
#
|
||||
# Search
|
||||
#
|
||||
db = solver.Phase(tables,
|
||||
solver.INT_VAR_DEFAULT,
|
||||
solver.INT_VALUE_DEFAULT);
|
||||
|
||||
solver.NewSearch(db, [objective])
|
||||
|
||||
while solver.NextSolution():
|
||||
print("z:", z)
|
||||
print("Table: ")
|
||||
for j in MRANGE:
|
||||
print(tables[j].Value(), " ");
|
||||
print()
|
||||
|
||||
for i in NRANGE:
|
||||
print("Table %d: " % i);
|
||||
for j in MRANGE:
|
||||
if tables[j].Value() == i:
|
||||
print(names[j] + " ")
|
||||
print()
|
||||
|
||||
print()
|
||||
|
||||
solver.EndSearch()
|
||||
|
||||
print()
|
||||
print("Solutions: %d" % solver.Solutions())
|
||||
print("WallTime: %dms" % solver.WallTime())
|
||||
print("Failures: %d" % solver.Failures())
|
||||
print("Branches: %d" % solver.Branches())
|
||||
|
||||
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
main()
|
||||
Reference in New Issue
Block a user