mpsgen.cc

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/*
 *  Copyright 2007 Martin von Gagern
 *
 *
 *  This file is part of mqn2mps.
 *
 *  mqn2mps is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  mqn2mps is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include <vector>
#include <limits>
#include <coin/CoinPackedMatrix.hpp>
#include <coin/CoinMpsIO.hpp>

#include "driver.hh"
#include "bounds.hh"
#include "mipgen.hh"
#include "mpsgen.hh"

/**
 * @file
 * Implementation of class mpsgen
 */

/**
 * Constructor.
 * The mpsgen::matrix element will be constructed in
 * mpsgen::make_matrix(), not in the constructor.
 */
mpsgen::mpsgen(const driver& d) : mipgen(d), matrix(0) {
}

/**
 * Destructor.
 * Deletes mpsgen::matrix if it has been created.
 * As mipgen::~mipgen is a virtual destructor, this destructor will
 * get called even if the object is referenced through a pointer to
 * mipgen.
 */
mpsgen::~mpsgen() {
  if (matrix) delete matrix;
}

/**
 * Write output to named file.
 * Bounds are set using operations on the CoinPackedMatrix. Then the
 * problem is written to the specified file.
 *
 * @bug Passing a 0 pointer as file name should result in the problem
 * being written to standard output, but the current version of
 * CoinUtils seems incapable of this, as it wants to append @c .mps to
 * any file name not already ending with that extension.
 *
 * @param filename the file to which output will be written
 */
void mpsgen::write(const char* filename) {
  CoinMpsIO io;
  size_t rows = row_names.size(), cols = col_names.size();
  double infinity = io.getInfinity();
  double *collb = new double[cols], *colub = new double[cols];
  double *obj = new double[cols];
  char *integrality = new char[cols];
  double *rowlb = new double[rows], *rowub = new double[rows];

  for (size_t col = 0; col < cols; ++col) {
    collb[col] = col_bounds[col].lower(false, -infinity);
    colub[col] = col_bounds[col].upper(false, infinity);
    obj[col] = col < modcount ? 0 : 1;
    integrality[col] = 1;
  }
  for (size_t row = 0; row < rows; ++row) {
    rowlb[row] = row_bounds[row].lower(false, -infinity);
    rowub[row] = row_bounds[row].upper(false, infinity);
  }

  io.setMpsData(*matrix,
                infinity, collb, colub, obj, integrality, rowlb, rowub,
                col_names, row_names);
  io.setProblemName(drv.name.c_str());
  io.writeMps(filename ? filename : "/dev/stdout");

  delete[] collb;
  delete[] colub;
  delete[] obj;
  delete[] integrality;
  delete[] rowlb;
  delete[] rowub;
}

/**
 * Allocates a CoinPackedMatrix data structure.
 *
 * @param rows the number of rows the coefficient matrix has.
 * @param cols the number of columns the coefficient matrix has.
 */
void mpsgen::make_matrix(size_t rows, size_t cols) {
  if (matrix) delete matrix;
  matrix = new CoinPackedMatrix();
  matrix->setDimensions(rows, cols);
}

/**
 * Set a single matrix element.
 *
 * This implementation skips zero elements.
 * Nonzero elements will be stored in the matrix.
 *
 * @param row the row index of the matrix element.
 * @param col the column index of the matrix element.
 * @param val the value of the matrix element.
 */
void mpsgen::set_element(size_t row, size_t col, int val) {
  if (val) matrix->modifyCoefficient(row, col, val);
}

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