Clp trunk
ClpPresolve Class Reference

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

#include <ClpPresolve.hpp>

Collaboration diagram for ClpPresolve:

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

ClpSimplexpresolvedModel (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 dropNames=false, bool doRowObjective=false)
 This version saves data in a file.
ClpSimplexmodel () const
 Return pointer to presolved model, Up to user to destroy.
ClpSimplexoriginalModel () 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.
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

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 ClpSimplexgutsOfPresolvedModel (ClpSimplex *originalModel, double feasibilityTolerance, bool keepIntegers, int numberPasses, bool dropNames, bool doRowObjective)
 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 
)
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 74 of file ClpPresolve.hpp.

double ClpPresolve::nonLinearValue ( ) const [inline]

Definition at line 77 of file ClpPresolve.hpp.

bool ClpPresolve::doDual ( ) const [inline]

Whether we want to do dual part of presolve.

Definition at line 81 of file ClpPresolve.hpp.

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

Definition at line 84 of file ClpPresolve.hpp.

bool ClpPresolve::doSingleton ( ) const [inline]

Whether we want to do singleton part of presolve.

Definition at line 89 of file ClpPresolve.hpp.

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

Definition at line 92 of file ClpPresolve.hpp.

bool ClpPresolve::doDoubleton ( ) const [inline]

Whether we want to do doubleton part of presolve.

Definition at line 97 of file ClpPresolve.hpp.

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

Definition at line 100 of file ClpPresolve.hpp.

bool ClpPresolve::doTripleton ( ) const [inline]

Whether we want to do tripleton part of presolve.

Definition at line 105 of file ClpPresolve.hpp.

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

Definition at line 108 of file ClpPresolve.hpp.

bool ClpPresolve::doTighten ( ) const [inline]

Whether we want to do tighten part of presolve.

Definition at line 113 of file ClpPresolve.hpp.

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

Definition at line 116 of file ClpPresolve.hpp.

bool ClpPresolve::doForcing ( ) const [inline]

Whether we want to do forcing part of presolve.

Definition at line 121 of file ClpPresolve.hpp.

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

Definition at line 124 of file ClpPresolve.hpp.

bool ClpPresolve::doImpliedFree ( ) const [inline]

Whether we want to do impliedfree part of presolve.

Definition at line 129 of file ClpPresolve.hpp.

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

Definition at line 132 of file ClpPresolve.hpp.

bool ClpPresolve::doDupcol ( ) const [inline]

Whether we want to do dupcol part of presolve.

Definition at line 137 of file ClpPresolve.hpp.

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

Definition at line 140 of file ClpPresolve.hpp.

bool ClpPresolve::doDuprow ( ) const [inline]

Whether we want to do duprow part of presolve.

Definition at line 145 of file ClpPresolve.hpp.

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

Definition at line 148 of file ClpPresolve.hpp.

bool ClpPresolve::doSingletonColumn ( ) const [inline]

Whether we want to do singleton column part of presolve.

Definition at line 153 of file ClpPresolve.hpp.

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

Definition at line 156 of file ClpPresolve.hpp.

bool ClpPresolve::doGubrow ( ) const [inline]

Whether we want to do gubrow part of presolve.

Definition at line 161 of file ClpPresolve.hpp.

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

Definition at line 164 of file ClpPresolve.hpp.

int ClpPresolve::presolveActions ( ) const [inline]

Set whole group.

Definition at line 169 of file ClpPresolve.hpp.

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

Definition at line 172 of file ClpPresolve.hpp.

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

Substitution level.

Definition at line 176 of file ClpPresolve.hpp.

void ClpPresolve::statistics ( ) [inline]

Asks for statistics.

Definition at line 180 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 
) [protected, virtual]

This is main part of Presolve.


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