61 lines
1.9 KiB
Python
61 lines
1.9 KiB
Python
# Copyright 2010-2017 Google
|
|
# 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.
|
|
"""Code sample that solves a model and displays all solutions."""
|
|
|
|
from __future__ import absolute_import
|
|
from __future__ import division
|
|
from __future__ import print_function
|
|
|
|
from ortools.sat.python import cp_model
|
|
|
|
|
|
class VarArraySolutionPrinter(cp_model.CpSolverSolutionCallback):
|
|
"""Print intermediate solutions."""
|
|
|
|
def __init__(self, variables):
|
|
cp_model.CpSolverSolutionCallback.__init__(self)
|
|
self.__variables = variables
|
|
self.__solution_count = 0
|
|
|
|
def OnSolutionCallback(self):
|
|
self.__solution_count += 1
|
|
for v in self.__variables:
|
|
print('%s=%i' % (v, self.Value(v)), end=' ')
|
|
print()
|
|
|
|
def SolutionCount(self):
|
|
return self.__solution_count
|
|
|
|
|
|
def SolveAllSolutions():
|
|
"""Showcases calling the solver to search for all solutions."""
|
|
# Creates the model.
|
|
model = cp_model.CpModel()
|
|
# Creates the variables.
|
|
num_vals = 3
|
|
x = model.NewIntVar(0, num_vals - 1, 'x')
|
|
y = model.NewIntVar(0, num_vals - 1, 'y')
|
|
z = model.NewIntVar(0, num_vals - 1, 'z')
|
|
# Create the constraints.
|
|
model.Add(x != y)
|
|
|
|
# Create a solver and solve.
|
|
solver = cp_model.CpSolver()
|
|
solution_printer = VarArraySolutionPrinter([x, y, z])
|
|
status = solver.SearchForAllSolutions(model, solution_printer)
|
|
print('Status = %s' % solver.StatusName(status))
|
|
print('Number of solutions found: %i' % solution_printer.SolutionCount())
|
|
|
|
|
|
SolveAllSolutions()
|