# ClpPresolve Class Reference

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

`#include <ClpPresolve.hpp>`

Collaboration diagram for ClpPresolve:
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List of all members.

## 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, const char *prohibitedRows=NULL, const char *prohibitedColumns=NULL)
int | presolvedModelToFile (ClpSimplex &si, std::string fileName, double feasibilityTolerance=0.0, bool keepIntegers=true, int numberPasses=5, bool dropNames=false, 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)
bool | doTwoxTwo () const
| Whether we want to do twoxtwo part of presolve.
void | setDoTwoxtwo (bool doTwoxTwo)
int | presolveActions () const
| Set whole group.
void | setPresolveActions (int action)
void | setSubstitution (int value)
| Substitution level.
void | statistics ()
| Asks for statistics.
int | presolveStatus () const
| Return presolve status (0,1,2).
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).
## private or protected data
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_
CoinBigIndex | nelems_
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.
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, const char *prohibitedRows=NULL, const char *prohibitedColumns=NULL)
| This is main part of Presolve.

## Detailed Description

This is the Clp interface to CoinPresolve.

Definition at line 15 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`,
|  | const char * | prohibitedRows = `NULL`,
|  | const char * | prohibitedColumns = `NULL` |
| ) |  |  |

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

This version saves data in a file.

The passed in model is updated to be presolved model. 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 76 of file ClpPresolve.hpp.

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

Definition at line 79 of file ClpPresolve.hpp.

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

Whether we want to do dual part of presolve.

Definition at line 83 of file ClpPresolve.hpp.

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

Definition at line 86 of file ClpPresolve.hpp.

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

Whether we want to do singleton part of presolve.

Definition at line 91 of file ClpPresolve.hpp.

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

Definition at line 94 of file ClpPresolve.hpp.

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

Whether we want to do doubleton part of presolve.

Definition at line 99 of file ClpPresolve.hpp.

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

Definition at line 102 of file ClpPresolve.hpp.

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

Whether we want to do tripleton part of presolve.

Definition at line 107 of file ClpPresolve.hpp.

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

Definition at line 110 of file ClpPresolve.hpp.

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

Whether we want to do tighten part of presolve.

Definition at line 115 of file ClpPresolve.hpp.

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

Definition at line 118 of file ClpPresolve.hpp.

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

Whether we want to do forcing part of presolve.

Definition at line 123 of file ClpPresolve.hpp.

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

Definition at line 126 of file ClpPresolve.hpp.

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

Whether we want to do impliedfree part of presolve.

Definition at line 131 of file ClpPresolve.hpp.

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

Definition at line 134 of file ClpPresolve.hpp.

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

Whether we want to do dupcol part of presolve.

Definition at line 139 of file ClpPresolve.hpp.

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

Definition at line 142 of file ClpPresolve.hpp.

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

Whether we want to do duprow part of presolve.

Definition at line 147 of file ClpPresolve.hpp.

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

Definition at line 150 of file ClpPresolve.hpp.

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

Whether we want to do singleton column part of presolve.

Definition at line 155 of file ClpPresolve.hpp.

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

Definition at line 158 of file ClpPresolve.hpp.

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

Whether we want to do gubrow part of presolve.

Definition at line 163 of file ClpPresolve.hpp.

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

Definition at line 166 of file ClpPresolve.hpp.

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

Whether we want to do twoxtwo part of presolve.

Definition at line 171 of file ClpPresolve.hpp.

void ClpPresolve::setDoTwoxtwo | ( | bool | doTwoxTwo | ) | `[inline]`

Definition at line 174 of file ClpPresolve.hpp.

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

Set whole group.

Definition at line 179 of file ClpPresolve.hpp.

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

Definition at line 182 of file ClpPresolve.hpp.

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

Substitution level.

Definition at line 186 of file ClpPresolve.hpp.

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

Asks for statistics.

Definition at line 190 of file ClpPresolve.hpp.

int ClpPresolve::presolveStatus | ( |  | ) | const

Return presolve status (0,1,2).

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,
|  | const char * | prohibitedRows = `NULL`,
|  | const char * | prohibitedColumns = `NULL` |
| ) |  |  | `[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 212 of file ClpPresolve.hpp.

ClpSimplex* ClpPresolve::presolvedModel_`[private]`

ClpPresolved model - up to user to destroy by deleteClpPresolvedModel.

Definition at line 215 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 221 of file ClpPresolve.hpp.

int* ClpPresolve::originalColumn_`[private]`

Original column numbers.

Definition at line 223 of file ClpPresolve.hpp.

int* ClpPresolve::originalRow_`[private]`

Original row numbers.

Definition at line 225 of file ClpPresolve.hpp.

double* ClpPresolve::rowObjective_`[private]`

Row objective.

Definition at line 227 of file ClpPresolve.hpp.

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

The list of transformations applied.

Definition at line 229 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 236 of file ClpPresolve.hpp.

int ClpPresolve::nrows_`[private]`

Definition at line 237 of file ClpPresolve.hpp.

CoinBigIndex ClpPresolve::nelems_`[private]`

Definition at line 238 of file ClpPresolve.hpp.

int ClpPresolve::numberPasses_`[private]`

Number of major passes.

Definition at line 240 of file ClpPresolve.hpp.

int ClpPresolve::substitution_`[private]`

Substitution level.

Definition at line 242 of file ClpPresolve.hpp.

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

Name of saved model file.

Definition at line 245 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 251 of file ClpPresolve.hpp.

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

- /home/coin/svn-release/Clp-1.15.11/Clp/src/ClpPresolve.hpp

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