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"""
A set partitioning model of a wedding seating problem
Authors: Stuart Mitchell 2009
"""
import pulp
max_tables = 5
max_table_size = 4
guests = 'A B C D E F G I J K L M N O P Q R'.split()
def happiness(table):
"""
Find the happiness of the table
- by calculating the maximum distance between the letters
"""
return abs(ord(table[0]) - ord(table[-1]))
#create list of all possible tables
possible_tables = [tuple(c) for c in pulp.allcombinations(guests,
max_table_size)]
#create a binary variable to state that a table setting is used
x = pulp.LpVariable.dicts('table', possible_tables,
lowBound = 0,
upBound = 1,
cat = pulp.LpInteger)
seating_model = pulp.LpProblem("Wedding Seating Model", pulp.LpMinimize)
seating_model += sum([happiness(table) * x[table] for table in possible_tables])
#specify the maximum number of tables
seating_model += sum([x[table] for table in possible_tables]) <= max_tables, \
"Maximum_number_of_tables"
#A guest must seated at one and only one table
for guest in guests:
seating_model += sum([x[table] for table in possible_tables
if guest in table]) == 1, "Must_seat_%s"%guest
seating_model.solve()
print("The choosen tables are out of a total of %s:"%len(possible_tables))
for table in possible_tables:
if x[table].value() == 1.0:
print(table)
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