71 lines
2.0 KiB
Python
Executable File
71 lines
2.0 KiB
Python
Executable File
#!/usr/bin/env python3
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# Copyright 2010-2021 Google LLC
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Showcases deep copying of a model."""
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# [START program]
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from ortools.sat.python import cp_model
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def CopyModelSat():
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"""Showcases printing intermediate solutions found during search."""
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# Creates the model.
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# [START model]
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model = cp_model.CpModel()
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# [END model]
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# Creates the variables.
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# [START variables]
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num_vals = 3
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x = model.NewIntVar(0, num_vals - 1, 'x')
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y = model.NewIntVar(0, num_vals - 1, 'y')
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z = model.NewIntVar(0, num_vals - 1, 'z')
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# [END variables]
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# Creates the constraints.
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# [START constraints]
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model.Add(x != y)
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# [END constraints]
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# [START objective]
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model.Maximize(x + 2 * y + 3 * z)
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# [END objective]
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# Creates a solver and solves.
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# [START solve]
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solver = cp_model.CpSolver()
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status = solver.Solve(model)
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# [END solve]
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if status == cp_model.OPTIMAL:
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print('Optimal value of the original model: {}'.format(
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solver.ObjectiveValue()))
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# Copy the model.
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copy = cp_model.CpModel()
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copy.CopyFrom(model)
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copy_x = copy.GetIntVarFromProtoIndex(x.Index())
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copy_y = copy.GetIntVarFromProtoIndex(y.Index())
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copy.Add(copy_x + copy_y <= 1)
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status = solver.Solve(copy)
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if status == cp_model.OPTIMAL:
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print('Optimal value of the modified model: {}'.format(
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solver.ObjectiveValue()))
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CopyModelSat()
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# [END program]
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