model_exporter.h

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// Copyright 2010-2018 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.

#ifndef OR_TOOLS_LINEAR_SOLVER_MODEL_EXPORTER_H_
#define OR_TOOLS_LINEAR_SOLVER_MODEL_EXPORTER_H_

#include <string>
#include <vector>

#include "absl/strings/str_format.h"
#include "ortools/base/hash.h"
#include "ortools/base/macros.h"
#include "ortools/base/statusor.h"
#include "ortools/linear_solver/linear_solver.pb.h"

namespace operations_research {

struct MPModelExportOptions {
  MPModelExportOptions() {}

  // Obfuscates variable and constraint names.
  bool obfuscate = false;
  // Whether to log invalid variable and constraint names.
  bool log_invalid_names = false;

  // For .lp files only. Decides whether variables unused in the objective and
  // constraints are shown when exported to a file.
  bool show_unused_variables = false;
  // For .lp files only. Maximum line length in exported files. The default
  // was chosen so that SCIP can read the files.
  int max_line_length = 10000;
};

// Outputs the current model (variables, constraints, objective) as a
// std::string encoded in the so-called "CPLEX LP file format" as generated by
// SCIP. The LP file format is easily readable by a human.
//
// Returns false if some error has occurred during execution.
// The validity of names is automatically checked. If a variable name or a
// constraint name is invalid or non-existent, a new valid name is
// automatically generated.
//
// If 'obfuscated' is true, the variable and constraint names of proto_
// are not used.  Variable and constraint names of the form "V12345"
// and "C12345" are used instead.
//
// For more information about the different LP file formats:
// http://lpsolve.sourceforge.net/5.5/lp-format.htm
// The following give a reasonable idea of the CPLEX LP file format:
// http://lpsolve.sourceforge.net/5.5/CPLEX-format.htm
// http://tinyurl.com/cplex-lp-format
// http://www.gurobi.com/documentation/5.1/reference-manual/node871
util::StatusOr<std::string> ExportModelAsLpFormat(
    const MPModelProto& model,
    const MPModelExportOptions& options = MPModelExportOptions());

// Outputs the current model (variables, constraints, objective) as a
// std::string encoded in MPS file format, using the "free" MPS format.
//
// Returns false if some error has occurred during execution. Models with
// maximization objectives trigger an error, because MPS can encode only
// minimization problems.
//
// The validity of names is automatically checked. If a variable name or a
// constraint name is invalid or non-existent, a new valid name is
// automatically generated.
//
// Name validity and obfuscation works exactly as in ExportModelAsLpFormat().
//
// For more information about the MPS format:
// http://en.wikipedia.org/wiki/MPS_(format)
// A close-to-original description coming from OSL:
// http://tinyurl.com/mps-format-by-osl
// A recent description from CPLEX:
// http://tinyurl.com/mps-format-by-cplex
// CPLEX extensions:
// http://tinyurl.com/mps-extensions-by-cplex
// Gurobi's description:
// http://www.gurobi.com/documentation/5.1/reference-manual/node869
util::StatusOr<std::string> ExportModelAsMpsFormat(
    const MPModelProto& model,
    const MPModelExportOptions& options = MPModelExportOptions());

}  // namespace operations_research

#endif  // OR_TOOLS_LINEAR_SOLVER_MODEL_EXPORTER_H_