model_util.cc

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// Copyright 2010-2022 Google LLC
// 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.
 
#include "ortools/math_opt/constraints/util/model_util.h"
 
#include <utility>
 
#include "ortools/math_opt/storage/model_storage.h"
#include "ortools/math_opt/storage/sparse_coefficient_map.h"
 
namespace operations_research::math_opt {
 
LinearExpression ToLinearExpression(const ModelStorage& storage,
                                    const SparseCoefficientMap& coeffs,
                                    const double offset) {
  LinearExpression expr = offset;
  for (const auto [var_id, coeff] : coeffs.terms()) {
    expr += coeff * Variable(&storage, var_id);
  }
  return expr;
}
 
std::pair<SparseCoefficientMap, double> FromLinearExpression(
    const LinearExpression& expression) {
  SparseCoefficientMap coeffs;
  for (const auto [var, coeff] : expression.terms()) {
    coeffs.set(var.typed_id(), coeff);
  }
  return {coeffs, expression.offset()};
}
 
}  // namespace operations_research::math_opt