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# ClpPresolve Class Reference

This is the Clp interface to CoinPresolve. More...

`#include <ClpPresolve.hpp>`

Collaboration diagram for ClpPresolve:

[legend]
List of all members.

## private or protected data
virtual const CoinPresolveAction * | presolve (CoinPresolveMatrix *prob)
| If you want to apply the individual presolve routines differently, or perhaps add your own to the mix, define a derived class and override this method.
virtual void | postsolve (CoinPostsolveMatrix &prob)
| Postsolving is pretty generic; just apply the transformations in reverse order.
virtual ClpSimplex * | gutsOfPresolvedModel (ClpSimplex *originalModel, double feasibilityTolerance, bool keepIntegers, int numberPasses, bool dropNames, bool doRowObjective)
| This is main part of Presolve.
ClpSimplex * | originalModel_
| Original model - must not be destroyed before postsolve.
ClpSimplex * | presolvedModel_
| ClpPresolved model - up to user to destroy by deleteClpPresolvedModel.
double | nonLinearValue_
| "Magic" number.
int * | originalColumn_
| Original column numbers.
int * | originalRow_
| Original row numbers.
double * | rowObjective_
| Row objective.
const CoinPresolveAction * | paction_
| The list of transformations applied.
int | ncols_
| The postsolved problem will expand back to its former size as postsolve transformations are applied.
int | nrows_
| If you want to apply the individual presolve routines differently, or perhaps add your own to the mix, define a derived class and override this method.
CoinBigIndex | nelems_
| If you want to apply the individual presolve routines differently, or perhaps add your own to the mix, define a derived class and override this method.
int | numberPasses_
| Number of major passes.
int | substitution_
| Substitution level.
std::string | saveFile_
| Name of saved model file.
int | presolveActions_
| Whether we want to skip dual part of presolve etc.
## Public Member Functions
Main Constructor, destructor
| ClpPresolve ()
| Default constructor.
virtual | ~ClpPresolve ()
| Virtual destructor.
presolve - presolves a model, transforming the model
and saving information in the ClpPresolve object needed for postsolving. This underlying (protected) method is virtual; the idea is that in the future, one could override this method to customize how the various presolve techniques are applied. This version of presolve returns a pointer to a new presolved model. NULL if infeasible or unbounded. This should be paired with postsolve below. The advantage of going back to original model is that it will be exactly as it was i.e. 0.0 will not become 1.0e-19. If keepIntegers is true then bounds may be tightened in original. Bounds will be moved by up to feasibilityTolerance to try and stay feasible. Names will be dropped in presolved model if asked
ClpSimplex * | presolvedModel (ClpSimplex &si, double feasibilityTolerance=0.0, bool keepIntegers=true, int numberPasses=5, bool dropNames=false, bool doRowObjective=false)
int | presolvedModelToFile (ClpSimplex &si, std::string fileName, double feasibilityTolerance=0.0, bool keepIntegers=true, int numberPasses=5, bool doRowObjective=false)
| This version saves data in a file.
ClpSimplex * | model () const
| Return pointer to presolved model, Up to user to destroy.
ClpSimplex * | originalModel () const
| Return pointer to original model.
void | setOriginalModel (ClpSimplex *model)
| Set pointer to original model.
const int * | originalColumns () const
| return pointer to original columns
const int * | originalRows () const
| return pointer to original rows
void | setNonLinearValue (double value)
| "Magic" number.
double | nonLinearValue () const
bool | doDual () const
| Whether we want to do dual part of presolve.
void | setDoDual (bool doDual)
bool | doSingleton () const
| Whether we want to do singleton part of presolve.
void | setDoSingleton (bool doSingleton)
bool | doDoubleton () const
| Whether we want to do doubleton part of presolve.
void | setDoDoubleton (bool doDoubleton)
bool | doTripleton () const
| Whether we want to do tripleton part of presolve.
void | setDoTripleton (bool doTripleton)
bool | doTighten () const
| Whether we want to do tighten part of presolve.
void | setDoTighten (bool doTighten)
bool | doForcing () const
| Whether we want to do forcing part of presolve.
void | setDoForcing (bool doForcing)
bool | doImpliedFree () const
| Whether we want to do impliedfree part of presolve.
void | setDoImpliedFree (bool doImpliedfree)
bool | doDupcol () const
| Whether we want to do dupcol part of presolve.
void | setDoDupcol (bool doDupcol)
bool | doDuprow () const
| Whether we want to do duprow part of presolve.
void | setDoDuprow (bool doDuprow)
bool | doSingletonColumn () const
| Whether we want to do singleton column part of presolve.
void | setDoSingletonColumn (bool doSingleton)
bool | doGubrow () const
| Whether we want to do gubrow part of presolve.
void | setDoGubrow (bool doGubrow)
int | presolveActions () const
| Set whole group.
void | setPresolveActions (int action)
void | setSubstitution (int value)
| Substitution level.
void | statistics ()
| Asks for statistics.
postsolve - postsolve the problem. If the problem
has not been solved to optimality, there are no guarantees. If you are using an algorithm like simplex that has a concept of "basic" rows/cols, then set updateStatus Note that if you modified the original problem after presolving, then you must ``undo'' these modifications before calling postsolve. This version updates original
virtual void | postsolve (bool updateStatus=true)
void | destroyPresolve ()
| Gets rid of presolve actions (e.g.when infeasible).

## Detailed Description

This is the Clp interface to CoinPresolve.

Definition at line 14 of file ClpPresolve.hpp.

## Constructor & Destructor Documentation

ClpPresolve::ClpPresolve | ( |  | ) |

Default constructor.

virtual ClpPresolve::~ClpPresolve | ( |  | ) | `[virtual]`

Virtual destructor.

## Member Function Documentation

ClpSimplex* ClpPresolve::presolvedModel | ( | ClpSimplex & | si,
|  | double | feasibilityTolerance = `0.0`,
|  | bool | keepIntegers = `true`,
|  | int | numberPasses = `5`,
|  | bool | dropNames = `false`,
|  | bool | doRowObjective = `false` |
| ) |  |  |

int ClpPresolve::presolvedModelToFile | ( | ClpSimplex & | si,
|  | std::string | fileName,
|  | double | feasibilityTolerance = `0.0`,
|  | bool | keepIntegers = `true`,
|  | int | numberPasses = `5`,
|  | bool | doRowObjective = `false` |
| ) |  |  |

This version saves data in a file.

The passed in model is updated to be presolved model. names are always dropped. Returns non-zero if infeasible

ClpSimplex* ClpPresolve::model | ( |  | ) | const

Return pointer to presolved model, Up to user to destroy.

ClpSimplex* ClpPresolve::originalModel | ( |  | ) | const

Return pointer to original model.

void ClpPresolve::setOriginalModel | ( | ClpSimplex * | model | ) |

Set pointer to original model.

const int* ClpPresolve::originalColumns | ( |  | ) | const

return pointer to original columns

const int* ClpPresolve::originalRows | ( |  | ) | const

return pointer to original rows

void ClpPresolve::setNonLinearValue | ( | double | value | ) | `[inline]`

"Magic" number.

If this is non-zero then any elements with this value may change and so presolve is very limited in what can be done to the row and column. This is for non-linear problems.

Definition at line 72 of file ClpPresolve.hpp.

References nonLinearValue_.

double ClpPresolve::nonLinearValue | ( |  | ) | const`[inline]`

Definition at line 74 of file ClpPresolve.hpp.

References nonLinearValue_.

bool ClpPresolve::doDual | ( |  | ) | const`[inline]`

Whether we want to do dual part of presolve.

Definition at line 77 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoDual | ( | bool | doDual | ) | `[inline]`

Definition at line 79 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doSingleton | ( |  | ) | const`[inline]`

Whether we want to do singleton part of presolve.

Definition at line 82 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoSingleton | ( | bool | doSingleton | ) | `[inline]`

Definition at line 84 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doDoubleton | ( |  | ) | const`[inline]`

Whether we want to do doubleton part of presolve.

Definition at line 87 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoDoubleton | ( | bool | doDoubleton | ) | `[inline]`

Definition at line 89 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doTripleton | ( |  | ) | const`[inline]`

Whether we want to do tripleton part of presolve.

Definition at line 92 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoTripleton | ( | bool | doTripleton | ) | `[inline]`

Definition at line 94 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doTighten | ( |  | ) | const`[inline]`

Whether we want to do tighten part of presolve.

Definition at line 97 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoTighten | ( | bool | doTighten | ) | `[inline]`

Definition at line 99 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doForcing | ( |  | ) | const`[inline]`

Whether we want to do forcing part of presolve.

Definition at line 102 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoForcing | ( | bool | doForcing | ) | `[inline]`

Definition at line 104 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doImpliedFree | ( |  | ) | const`[inline]`

Whether we want to do impliedfree part of presolve.

Definition at line 107 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoImpliedFree | ( | bool | doImpliedfree | ) | `[inline]`

Definition at line 109 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doDupcol | ( |  | ) | const`[inline]`

Whether we want to do dupcol part of presolve.

Definition at line 112 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoDupcol | ( | bool | doDupcol | ) | `[inline]`

Definition at line 114 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doDuprow | ( |  | ) | const`[inline]`

Whether we want to do duprow part of presolve.

Definition at line 117 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoDuprow | ( | bool | doDuprow | ) | `[inline]`

Definition at line 119 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doSingletonColumn | ( |  | ) | const`[inline]`

Whether we want to do singleton column part of presolve.

Definition at line 122 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoSingletonColumn | ( | bool | doSingleton | ) | `[inline]`

Definition at line 124 of file ClpPresolve.hpp.

References presolveActions_.

bool ClpPresolve::doGubrow | ( |  | ) | const`[inline]`

Whether we want to do gubrow part of presolve.

Definition at line 127 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setDoGubrow | ( | bool | doGubrow | ) | `[inline]`

Definition at line 129 of file ClpPresolve.hpp.

References presolveActions_.

int ClpPresolve::presolveActions | ( |  | ) | const`[inline]`

Set whole group.

Definition at line 132 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setPresolveActions | ( | int | action | ) | `[inline]`

Definition at line 134 of file ClpPresolve.hpp.

References presolveActions_.

void ClpPresolve::setSubstitution | ( | int | value | ) | `[inline]`

Substitution level.

Definition at line 137 of file ClpPresolve.hpp.

References substitution_.

void ClpPresolve::statistics | ( |  | ) | `[inline]`

Asks for statistics.

Definition at line 140 of file ClpPresolve.hpp.

References presolveActions_.

virtual void ClpPresolve::postsolve | ( | bool | updateStatus = `true` | ) | `[virtual]`

void ClpPresolve::destroyPresolve | ( |  | ) |

Gets rid of presolve actions (e.g.when infeasible).

virtual const CoinPresolveAction* ClpPresolve::presolve | ( | CoinPresolveMatrix * | prob | ) | `[protected, virtual]`

If you want to apply the individual presolve routines differently, or perhaps add your own to the mix, define a derived class and override this method.

virtual void ClpPresolve::postsolve | ( | CoinPostsolveMatrix & | prob | ) | `[protected, virtual]`

Postsolving is pretty generic; just apply the transformations in reverse order.

You will probably only be interested in overriding this method if you want to add code to test for consistency while debugging new presolve techniques.

virtual ClpSimplex* ClpPresolve::gutsOfPresolvedModel | ( | ClpSimplex * | originalModel,
|  | double | feasibilityTolerance,
|  | bool | keepIntegers,
|  | int | numberPasses,
|  | bool | dropNames,
|  | bool | doRowObjective |
| ) |  |  | `[protected, virtual]`

This is main part of Presolve.

## Member Data Documentation

ClpSimplex* ClpPresolve::originalModel_`[private]`

Original model - must not be destroyed before postsolve.

Definition at line 159 of file ClpPresolve.hpp.

ClpSimplex* ClpPresolve::presolvedModel_`[private]`

ClpPresolved model - up to user to destroy by deleteClpPresolvedModel.

Definition at line 162 of file ClpPresolve.hpp.

double ClpPresolve::nonLinearValue_`[private]`

"Magic" number.

If this is non-zero then any elements with this value may change and so presolve is very limited in what can be done to the row and column. This is for non-linear problems. One could also allow for cases where sign of coefficient is known.

Definition at line 168 of file ClpPresolve.hpp.

Referenced by nonLinearValue(), and setNonLinearValue().

int* ClpPresolve::originalColumn_`[private]`

Original column numbers.

Definition at line 170 of file ClpPresolve.hpp.

int* ClpPresolve::originalRow_`[private]`

Original row numbers.

Definition at line 172 of file ClpPresolve.hpp.

double* ClpPresolve::rowObjective_`[private]`

Row objective.

Definition at line 174 of file ClpPresolve.hpp.

const CoinPresolveAction* ClpPresolve::paction_`[private]`

The list of transformations applied.

Definition at line 176 of file ClpPresolve.hpp.

int ClpPresolve::ncols_`[private]`

The postsolved problem will expand back to its former size as postsolve transformations are applied.

It is efficient to allocate data structures for the final size of the problem rather than expand them as needed. These fields give the size of the original problem.

Definition at line 183 of file ClpPresolve.hpp.

int ClpPresolve::nrows_`[private]`

If you want to apply the individual presolve routines differently, or perhaps add your own to the mix, define a derived class and override this method.

Definition at line 184 of file ClpPresolve.hpp.

CoinBigIndex ClpPresolve::nelems_`[private]`

If you want to apply the individual presolve routines differently, or perhaps add your own to the mix, define a derived class and override this method.

Definition at line 185 of file ClpPresolve.hpp.

int ClpPresolve::numberPasses_`[private]`

Number of major passes.

Definition at line 187 of file ClpPresolve.hpp.

int ClpPresolve::substitution_`[private]`

Substitution level.

Definition at line 189 of file ClpPresolve.hpp.

Referenced by setSubstitution().

std::string ClpPresolve::saveFile_`[private]`

Name of saved model file.

Definition at line 192 of file ClpPresolve.hpp.

int ClpPresolve::presolveActions_`[private]`

Whether we want to skip dual part of presolve etc.

512 bit allows duplicate column processing on integer columns and dual stuff on integers

Definition at line 198 of file ClpPresolve.hpp.

Referenced by doDoubleton(), doDual(), doDupcol(), doDuprow(), doForcing(), doGubrow(), doImpliedFree(), doSingleton(), doSingletonColumn(), doTighten(), doTripleton(), presolveActions(), setDoDoubleton(), setDoDual(), setDoDupcol(), setDoDuprow(), setDoForcing(), setDoGubrow(), setDoImpliedFree(), setDoSingleton(), setDoSingletonColumn(), setDoTighten(), setDoTripleton(), setPresolveActions(), and statistics().

The documentation for this class was generated from the following file:

- /home/coin/SVN-release/Cgl-0.55.0/Clp/src/ClpPresolve.hpp