78 lines
2.5 KiB
C++
78 lines
2.5 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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// Simple integer programming example
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#include <cmath>
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#include <iostream>
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#include <limits>
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#include <ostream>
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#include "absl/status/status.h"
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#include "absl/time/time.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/base/status_macros.h"
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#include "ortools/math_opt/cpp/math_opt.h"
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namespace {
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namespace math_opt = ::operations_research::math_opt;
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constexpr double kInf = std::numeric_limits<double>::infinity();
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// Model and solve the problem:
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// max x + 10 * y
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// s.t. x + 7 * y <= 17.5
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// x <= 3.5
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// x in {0.0, 1.0, 2.0, ...,
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// y in {0.0, 1.0, 2.0, ...,
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//
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absl::Status Main() {
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math_opt::Model model("Integer programming example");
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// Variables
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const math_opt::Variable x = model.AddIntegerVariable(0.0, kInf, "x");
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const math_opt::Variable y = model.AddIntegerVariable(0.0, kInf, "y");
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// Constraints
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model.AddLinearConstraint(x + 7 * y <= 17.5, "c1");
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model.AddLinearConstraint(x <= 3.5, "c2");
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// Objective
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model.Maximize(x + 10 * y);
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ASSIGN_OR_RETURN(const math_opt::SolveResult result,
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Solve(model, math_opt::SolverType::kGscip));
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RETURN_IF_ERROR(result.termination.EnsureIsOptimalOrFeasible());
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// A feasible solution is always available on termination reason kOptimal, and
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// kFeasible, but in the later case the solution may be sub-optimal.
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std::cout << "Problem solved in " << result.solve_time() << std::endl;
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std::cout << "Objective value: " << result.objective_value() << std::endl;
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std::cout << "Variable values: [x="
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<< std::round(result.variable_values().at(x))
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<< ", y=" << std::round(result.variable_values().at(y)) << "]"
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<< std::endl;
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return absl::OkStatus();
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}
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} // namespace
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int main(int argc, char** argv) {
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InitGoogle(argv[0], &argc, &argv, true);
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const absl::Status status = Main();
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if (!status.ok()) {
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LOG(QFATAL) << status;
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}
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return 0;
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}
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