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ortools-clone/examples/python/stable_marriage_sat.py
Laurent Perron 4e7bae206c polish examples
2018-09-18 13:31:08 +02:00

117 lines
4.0 KiB
Python

# Copyright 2018 Gergo Rozner
# 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.
"""Solves the stable marriage problem in CP-SAT."""
from ortools.sat.python import cp_model
class SolutionPrinter(cp_model.CpSolverSolutionCallback):
def __init__(self, wife, husband):
cp_model.CpSolverSolutionCallback.__init__(self)
self.__wife = wife
self.__husband = husband
self.__solution_count = 0
self.__n = len(wife)
def OnSolutionCallback(self):
self.__solution_count += 1
print("Solution %i" % self.__solution_count)
print("wife : ", [self.Value(self.__wife[i]) for i in range(self.__n)])
print("husband: ", [self.Value(self.__husband[i]) for i in range(self.__n)])
print()
def SolutionCount(self):
return self.__solution_count
def main(ranks, pair_num):
mrank = ranks["rankMen"]
wrank = ranks["rankWomen"]
n = pair_num
model = cp_model.CpModel()
wife = [model.NewIntVar(0, n - 1, "wife[%i]" % i) for i in range(n)]
husband = [model.NewIntVar(0, n - 1, "husband[%i]" % i) for i in range(n)]
for m in range(n):
model.AddElement(wife[m], husband, m)
for w in range(n):
model.AddElement(husband[w], wife, w)
#mrank[w][m] < mrank[w][husband[w]] => wrank[m][wife[m]] < wrank[m][w]
for w in range(n):
for m in range(n):
husband_rank = model.NewIntVar(1, n, "")
model.AddElement(husband[w], mrank[w], husband_rank)
wife_rank = model.NewIntVar(1, n, "")
model.AddElement(wife[m], wrank[m], wife_rank)
husband_dominated = model.NewBoolVar("")
model.Add(mrank[w][m] < husband_rank).OnlyEnforceIf(husband_dominated)
model.Add(mrank[w][m] >= husband_rank).OnlyEnforceIf(
husband_dominated.Not())
wife_dominates = model.NewBoolVar("")
model.Add(wife_rank < wrank[m][w]).OnlyEnforceIf(wife_dominates)
model.Add(wife_rank >= wrank[m][w]).OnlyEnforceIf(wife_dominates.Not())
model.AddImplication(husband_dominated, wife_dominates)
#wrank[m][w] < wrank[m][wife[m]] => mrank[w][husband[w]] < mrank[w][m]
for m in range(n):
for w in range(n):
wife_rank = model.NewIntVar(1, n, "")
model.AddElement(wife[m], wrank[m], wife_rank)
husband_rank = model.NewIntVar(1, n, "")
model.AddElement(husband[w], mrank[w], husband_rank)
wife_dominated = model.NewBoolVar("")
model.Add(wrank[m][w] < wife_rank).OnlyEnforceIf(wife_dominated)
model.Add(wrank[m][w] >= wife_rank).OnlyEnforceIf(wife_dominated.Not())
husband_dominates = model.NewBoolVar("")
model.Add(husband_rank < mrank[w][m]).OnlyEnforceIf(husband_dominates)
model.Add(husband_rank >= mrank[w][m]).OnlyEnforceIf(
husband_dominates.Not())
model.AddImplication(wife_dominated, husband_dominates)
solver = cp_model.CpSolver()
solution_printer = SolutionPrinter(wife, husband)
solver.SearchForAllSolutions(model, solution_printer)
if __name__ == "__main__":
rankings1 = {
"rankMen": [[1, 2, 3, 4], [4, 3, 2, 1], [1, 2, 3, 4], [3, 4, 1, 2]],
"rankWomen": [[1, 2, 3, 4], [2, 1, 3, 4], [1, 4, 3, 2], [4, 3, 1, 2]]
}
rankings2 = {
"rankMen": [[1, 5, 4, 6, 2, 3], [4, 1, 5, 2, 6, 3], [6, 4, 2, 1, 5, 3],
[1, 5, 2, 4, 3, 6], [4, 2, 1, 5, 6, 3], [2, 6, 3, 5, 1, 4]],
"rankWomen": [[1, 4, 2, 5, 6, 3], [3, 4, 6, 1, 5, 2], [1, 6, 4, 2, 3, 5],
[6, 5, 3, 4, 2, 1], [3, 1, 2, 4, 5, 6], [2, 3, 1, 6, 5, 4]]
}
problem = rankings2
couple_count = len(problem["rankMen"])
main(problem, couple_count)