77 lines
2.5 KiB
C++
77 lines
2.5 KiB
C++
// Copyright 2010-2024 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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#include "ortools/math_opt/cpp/objective.h"
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#include <optional>
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#include <ostream>
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#include <sstream>
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#include <string>
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#include "absl/log/check.h"
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#include "absl/strings/string_view.h"
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#include "ortools/math_opt/cpp/variable_and_expressions.h"
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#include "ortools/math_opt/storage/model_storage.h"
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#include "ortools/math_opt/storage/model_storage_types.h"
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namespace operations_research::math_opt {
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LinearExpression Objective::AsLinearExpression() const {
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CHECK_EQ(storage()->num_quadratic_objective_terms(id_), 0)
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<< "The objective function contains quadratic terms and cannot be "
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"represented as a LinearExpression";
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LinearExpression objective = offset();
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for (const auto [raw_var_id, coeff] : storage_->linear_objective(id_)) {
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objective += coeff * Variable(storage_, raw_var_id);
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}
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return objective;
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}
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QuadraticExpression Objective::AsQuadraticExpression() const {
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QuadraticExpression result = offset();
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for (const auto& [v, coef] : storage_->linear_objective(id_)) {
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result += coef * Variable(storage(), v);
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}
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for (const auto& [v1, v2, coef] : storage_->quadratic_objective_terms(id_)) {
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result +=
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QuadraticTerm(Variable(storage(), v1), Variable(storage(), v2), coef);
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}
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return result;
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}
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std::string Objective::ToString() const {
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if (!is_primary() && !storage()->has_auxiliary_objective(*id_)) {
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return std::string(kDeletedObjectiveDefaultDescription);
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}
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std::stringstream str;
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str << AsQuadraticExpression();
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return str.str();
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}
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std::ostream& operator<<(std::ostream& ostr, const Objective& objective) {
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// TODO(b/170992529): handle quoting of invalid characters in the name.
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const absl::string_view name = objective.name();
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if (name.empty()) {
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if (objective.is_primary()) {
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ostr << "__primary_obj__";
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} else {
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ostr << "__aux_obj#" << *objective.id() << "__";
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}
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} else {
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ostr << name;
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}
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return ostr;
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}
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} // namespace operations_research::math_opt
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