CoinPresolveZeros.hpp

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/* $Id: CoinPresolveZeros.hpp 1498 2011-11-02 15:25:35Z mjs $ */
// Copyright (C) 2002, International Business Machines
// Corporation and others.  All Rights Reserved.
// This code is licensed under the terms of the Eclipse Public License (EPL).

#ifndef CoinPresolveZeros_H
#define CoinPresolveZeros_H

#define DROP_ZERO       8

struct dropped_zero {
  int row;
  int col;
};

class drop_zero_coefficients_action : public CoinPresolveAction {

  const int nzeros_;
  const dropped_zero *const zeros_;

  drop_zero_coefficients_action(int nzeros,
                                const dropped_zero *zeros,
                                const CoinPresolveAction *next) :
    CoinPresolveAction(next),
    nzeros_(nzeros), zeros_(zeros)
{}

 public:
  const char *name() const { return ("drop_zero_coefficients_action"); }

  static const CoinPresolveAction *presolve(CoinPresolveMatrix *prob,
                                         int *checkcols,
                                         int ncheckcols,
                                         const CoinPresolveAction *next);

  void postsolve(CoinPostsolveMatrix *prob) const;

  virtual ~drop_zero_coefficients_action() { deleteAction(zeros_,dropped_zero*); }
};

const CoinPresolveAction *drop_zero_coefficients(CoinPresolveMatrix *prob,
                                              const CoinPresolveAction *next);

#endif