/usr/include/coin/CoinPresolveDupcol.hpp is in coinor-libcoinutils-dev 2.6.4-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 | /* $Id: CoinPresolveDupcol.hpp 1215 2009-11-05 11:03:04Z forrest $ */
// Copyright (C) 2002, International Business Machines
// Corporation and others. All Rights Reserved.
#ifndef CoinPresolveDupcol_H
#define CoinPresolveDupcol_H
#include "CoinPresolveMatrix.hpp"
/*!
\file
*/
#define DUPCOL 10
/*! \class dupcol_action
\brief Detect and remove duplicate columns
The general technique is to sum the coefficients a_(*,j) of each column.
Columns with identical sums are duplicates. The obvious problem is that,
<i>e.g.</i>, [1 0 1 0] and [0 1 0 1] both add to 2. To minimize the
chances of false positives, the coefficients of each row are multipled by
a random number r_i, so that we sum r_i*a_ij.
Candidate columns are checked to confirm they are identical. Where the
columns have the same objective coefficient, the two are combined. If the
columns have different objective coefficients, complications ensue. In order
to remove the duplicate, it must be possible to fix the variable at a bound.
*/
class dupcol_action : public CoinPresolveAction {
dupcol_action();
dupcol_action(const dupcol_action& rhs);
dupcol_action& operator=(const dupcol_action& rhs);
struct action {
double thislo;
double thisup;
double lastlo;
double lastup;
int ithis;
int ilast;
double *colels;
int nincol;
};
const int nactions_;
// actions_ is owned by the class and must be deleted at destruction
const action *const actions_;
dupcol_action(int nactions, const action *actions,
const CoinPresolveAction *next) :
CoinPresolveAction(next),
nactions_(nactions),
actions_(actions) {}
public:
const char *name() const;
static const CoinPresolveAction *presolve(CoinPresolveMatrix *prob,
const CoinPresolveAction *next);
void postsolve(CoinPostsolveMatrix *prob) const;
~dupcol_action();
};
/*! \class duprow_action
\brief Detect and remove duplicate rows
The algorithm to detect duplicate rows is as outlined for dupcol_action.
If the feasible interval for one constraint is strictly contained in the
other, the tighter (contained) constraint is kept. If the feasible
intervals are disjoint, the problem is infeasible. If the feasible
intervals overlap, both constraints are kept.
duprow_action is definitely a work in progress; #postsolve is
unimplemented.
This doesn't matter as it uses useless_constraint.
*/
class duprow_action : public CoinPresolveAction {
struct action {
int row;
double lbound;
double ubound;
};
const int nactions_;
const action *const actions_;
duprow_action():CoinPresolveAction(NULL),nactions_(0),actions_(NULL) {}
duprow_action(int nactions,
const action *actions,
const CoinPresolveAction *next) :
CoinPresolveAction(next),
nactions_(nactions), actions_(actions) {}
public:
const char *name() const;
static const CoinPresolveAction *presolve(CoinPresolveMatrix *prob,
const CoinPresolveAction *next);
void postsolve(CoinPostsolveMatrix *prob) const;
//~duprow_action() { delete[]actions_; }
};
/*! \class gubrow_action
\brief Detect and remove entries whose sum is known
If we have an equality row where all entries same then
For other rows where all entries for that equality row are same
then we can delete entries and modify rhs
gubrow_action is definitely a work in progress; #postsolve is
unimplemented.
*/
class gubrow_action : public CoinPresolveAction {
struct action {
int row;
double lbound;
double ubound;
};
const int nactions_;
const action *const actions_;
gubrow_action():CoinPresolveAction(NULL),nactions_(0),actions_(NULL) {}
gubrow_action(int nactions,
const action *actions,
const CoinPresolveAction *next) :
CoinPresolveAction(next),
nactions_(nactions), actions_(actions) {}
public:
const char *name() const;
static const CoinPresolveAction *presolve(CoinPresolveMatrix *prob,
const CoinPresolveAction *next);
void postsolve(CoinPostsolveMatrix *prob) const;
//~gubrow_action() { delete[]actions_; }
};
#endif
|