4f381f6d07
* bump abseil to 20250814 * bump protobuf to v32.0 * cmake: add ccache auto support * backport flatzinc, math_opt and sat update
80 lines
2.7 KiB
C++
80 lines
2.7 KiB
C++
// Copyright 2010-2025 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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// [START program]
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#include <stdlib.h>
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#include "absl/base/log_severity.h"
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#include "absl/log/globals.h"
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#include "absl/types/span.h"
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#include "ortools/base/init_google.h"
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#include "ortools/base/logging.h"
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#include "ortools/sat/cp_model.h"
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#include "ortools/sat/cp_model.pb.h"
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#include "ortools/sat/cp_model_solver.h"
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#include "ortools/sat/model.h"
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#include "ortools/sat/sat_parameters.pb.h"
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namespace operations_research {
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namespace sat {
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void ChannelingSampleSat() {
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// Create the CP-SAT model.
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CpModelBuilder cp_model;
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// Declare our two primary variables.
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const IntVar x = cp_model.NewIntVar({0, 10});
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const IntVar y = cp_model.NewIntVar({0, 10});
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// Declare our intermediate boolean variable.
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const BoolVar b = cp_model.NewBoolVar();
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// Implement b == (x >= 5).
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cp_model.AddGreaterOrEqual(x, 5).OnlyEnforceIf(b);
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cp_model.AddLessThan(x, 5).OnlyEnforceIf(~b);
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// Create our two half-reified constraints.
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// First, b implies (y == 10 - x).
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cp_model.AddEquality(x + y, 10).OnlyEnforceIf(b);
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// Second, not(b) implies y == 0.
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cp_model.AddEquality(y, 0).OnlyEnforceIf(~b);
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// Search for x values in increasing order.
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cp_model.AddDecisionStrategy({x}, DecisionStrategyProto::CHOOSE_FIRST,
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DecisionStrategyProto::SELECT_MIN_VALUE);
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// Create a solver and solve with a fixed search.
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Model model;
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SatParameters parameters;
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parameters.set_search_branching(SatParameters::FIXED_SEARCH);
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parameters.set_enumerate_all_solutions(true);
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model.Add(NewSatParameters(parameters));
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model.Add(NewFeasibleSolutionObserver([&](const CpSolverResponse& r) {
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LOG(INFO) << "x=" << SolutionIntegerValue(r, x)
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<< " y=" << SolutionIntegerValue(r, y)
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<< " b=" << SolutionBooleanValue(r, b);
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}));
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SolveCpModel(cp_model.Build(), &model);
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}
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} // namespace sat
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} // namespace operations_research
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int main(int argc, char* argv[]) {
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InitGoogle(argv[0], &argc, &argv, true);
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absl::SetStderrThreshold(absl::LogSeverityAtLeast::kInfo);
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operations_research::sat::ChannelingSampleSat();
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return EXIT_SUCCESS;
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}
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// [END program]
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