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SoPlex

Sequential object-oriented simPlex

SPxPricer< R > Class Template Referenceabstract

Abstract pricer base class.Class SPxPricer is a pure virtual class defining the interface for pricer classes to be used by SoPlex. The pricer's task is to select a vector to enter or leave the simplex basis, depending on the chosen simplex type. More...

#include <spxpricer.h>

Classes

struct  IdxCompare
 Compare class to sort idx/val pairs, used for hypersparse pricing leaving. More...
 
struct  IdxElement
 

Public Types

enum  ViolationType { NOT_VIOLATED = 0, VIOLATED = 1, VIOLATED_AND_CHECKED = 2 }
 

Public Member Functions

Initialization
virtual const char * getName () const
 get name of pricer. More...
 
virtual void load (SPxSolverBase< R > *p_solver)
 loads LP. More...
 
virtual void clear ()
 unloads LP. More...
 
virtual SPxSolverBase< R > * solver () const
 returns loaded SPxSolverBase object. More...
 
virtual void setPricingTolerance (R tol)
 sets pricing tolerance. More...
 
virtual R pricingTolerance () const
 returns the pricing tolerance More...
 
virtual void setTolerances (std::shared_ptr< Tolerances > newTolerances)
 set the _tolerances member variable More...
 
virtual void setType (typename SPxSolverBase< R >::Type)
 sets pricing type. More...
 
virtual void setRep (typename SPxSolverBase< R >::Representation)
 sets basis representation. More...
 
Pivoting
virtual int selectLeave ()=0
 returns selected index to leave basis. More...
 
virtual void left4 (int, SPxId)
 performs leaving pivot. More...
 
virtual SPxId selectEnter ()=0
 selects Id to enter basis. More...
 
virtual void entered4 (SPxId, int)
 performs entering pivot. More...
 
Extension
virtual void addedVecs (int)
 n vectors have been added to loaded LP. More...
 
virtual void addedCoVecs (int)
 n covectors have been added to loaded LP. More...
 
Shrinking
virtual void removedVec (int)
 vector i was removed from loaded LP. More...
 
virtual void removedVecs (const int *)
 vectors given by perm have been removed from loaded LP. More...
 
virtual void removedCoVec (int)
 covector i was removed from loaded LP. More...
 
virtual void removedCoVecs (const int *)
 covectors given by perm have been removed from loaded LP. More...
 
Debugging
virtual bool isConsistent () const
 
Constructors / Destructors
 SPxPricer (const char *p_name)
 constructor More...
 
 SPxPricer (const SPxPricer &old)
 copy constructor More...
 
SPxPriceroperator= (const SPxPricer &rhs)
 assignment operator More...
 
virtual ~SPxPricer ()
 destructor. More...
 
virtual SPxPricerclone () const =0
 clone function for polymorphism More...
 

Protected Attributes

IdxCompare compare
 
Data
const char * m_name
 name of the pricer More...
 
SPxSolverBase< R > * thesolver
 the solver More...
 
thetolerance
 violation bound More...
 
std::shared_ptr< Tolerances_tolerances
 tolerances used by the solver More...
 

Detailed Description

template<class R>
class soplex::SPxPricer< R >

Abstract pricer base class.

Class SPxPricer is a pure virtual class defining the interface for pricer classes to be used by SoPlex. The pricer's task is to select a vector to enter or leave the simplex basis, depending on the chosen simplex type.

An SPxPricer first loads the SoPlex object for which pricing is to be performed. Then, depending of the SPxSolverBase<R>::Type, methods selectEnter() and entered4() (for entering Simplex) or selectLeave() and left4() (for leaving Simplex) are called by SoPlex. The SPxPricer object is informed of a change of the SPxSolverBase<R>::Type by calling method setType().

Definition at line 56 of file spxpricer.h.

Member Enumeration Documentation

◆ ViolationType

Enumerator
NOT_VIOLATED 
VIOLATED 
VIOLATED_AND_CHECKED 

Definition at line 108 of file spxpricer.h.

Constructor & Destructor Documentation

◆ SPxPricer() [1/2]

SPxPricer ( const char *  p_name)
explicit

constructor

Definition at line 284 of file spxpricer.h.

◆ SPxPricer() [2/2]

SPxPricer ( const SPxPricer< R > &  old)

copy constructor

Definition at line 291 of file spxpricer.h.

◆ ~SPxPricer()

virtual ~SPxPricer ( )
virtual

destructor.

Definition at line 312 of file spxpricer.h.

Member Function Documentation

◆ addedCoVecs()

virtual void addedCoVecs ( int  )
virtual

n covectors have been added to loaded LP.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxWeightPR< R >, SPxDevexPR< R >, SPxDevexPR< BP >, and SPxHybridPR< R >.

Definition at line 246 of file spxpricer.h.

◆ addedVecs()

virtual void addedVecs ( int  )
virtual

n vectors have been added to loaded LP.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxWeightPR< R >, SPxDevexPR< R >, SPxDevexPR< BP >, and SPxHybridPR< R >.

Definition at line 243 of file spxpricer.h.

◆ clear()

virtual void clear ( )
virtual

unloads LP.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, and SPxHybridPR< R >.

Definition at line 133 of file spxpricer.h.

◆ clone()

◆ entered4()

virtual void entered4 ( SPxId  ,
int   
)
virtual

performs entering pivot.

Method entered4() is called after each simplex iteration in ENTER mode. It informs the SPxPricer that variable id has entered at the n 'th position. When being called, all vectors of SoPlex involved in such an entering update are setup correctly and may be accessed via the corresponding methods (fVec(), pVec(), etc.). In general, argument id will be the one returned by the SPxPricer at the previous call to selectEnter(). However, one can not rely on this.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxDevexPR< R >, SPxDevexPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, and SPxHybridPR< R >.

Definition at line 234 of file spxpricer.h.

◆ getName()

virtual const char* getName ( ) const
virtual

get name of pricer.

Definition at line 119 of file spxpricer.h.

◆ isConsistent()

virtual bool isConsistent ( ) const
virtual

◆ left4()

virtual void left4 ( int  ,
SPxId   
)
virtual

performs leaving pivot.

Method left4() is called after each simplex iteration in LEAVE mode. It informs the SPxPricer that the n 'th variable has left the basis for id to come in at this position. When being called, all vectors of SoPlex involved in such an entering update are setup correctly and may be accessed via the corresponding methods (fVec(), pVec(), etc.). In general, argument n will be the one returned by the SPxPricer at the previous call to selectLeave(). However, one can not rely on this.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxDevexPR< R >, SPxDevexPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, and SPxHybridPR< R >.

Definition at line 206 of file spxpricer.h.

◆ load()

virtual void load ( SPxSolverBase< R > *  p_solver)
virtual

loads LP.

Loads the solver and LP for which pricing steps are to be performed.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxWeightPR< R >, SPxParMultPR< R >, SPxParMultPR< BP >, SPxDevexPR< R >, SPxDevexPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, and SPxHybridPR< R >.

Definition at line 127 of file spxpricer.h.

◆ operator=()

◆ pricingTolerance()

virtual R pricingTolerance ( ) const
virtual

returns the pricing tolerance

Definition at line 154 of file spxpricer.h.

◆ removedCoVec()

virtual void removedCoVec ( int  )
virtual

covector i was removed from loaded LP.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, and SPxWeightPR< R >.

Definition at line 260 of file spxpricer.h.

◆ removedCoVecs()

virtual void removedCoVecs ( const int *  )
virtual

covectors given by perm have been removed from loaded LP.

Definition at line 263 of file spxpricer.h.

◆ removedVec()

virtual void removedVec ( int  )
virtual

vector i was removed from loaded LP.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, and SPxWeightPR< R >.

Definition at line 254 of file spxpricer.h.

◆ removedVecs()

virtual void removedVecs ( const int *  )
virtual

vectors given by perm have been removed from loaded LP.

Definition at line 257 of file spxpricer.h.

◆ selectEnter()

virtual SPxId selectEnter ( )
pure virtual

selects Id to enter basis.

Selects the SPxId of a vector to enter the basis. The selected id, must not represent a basic index (i.e. solver()->isBasic(id) must be false). However, the corresponding test value needs not to be less than -#tolerance(). If not, SoPlex will discard the pivot.

Note: When method selectEnter() is called by the loaded SoPlex object, all values from coTest() are up to date. However, whether the elements of test() are up to date depends on the SPxSolverBase<R>::Pricing type.

Implemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxWeightPR< R >, SPxDevexPR< R >, SPxDevexPR< BP >, SPxParMultPR< R >, SPxParMultPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, SPxDantzigPR< R >, SPxDantzigPR< BP >, and SPxHybridPR< R >.

Referenced by SPxPricer< BP >::left4().

◆ selectLeave()

virtual int selectLeave ( )
pure virtual

returns selected index to leave basis.

Selects the index of a vector to leave the basis. The selected index i, say, must be in the range 0 <= i < solver()->dim() and its tested value must fullfill solver()->test()[i] < -#tolerance().

Implemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxWeightPR< R >, SPxDevexPR< R >, SPxDevexPR< BP >, SPxParMultPR< R >, SPxParMultPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, SPxDantzigPR< R >, SPxDantzigPR< BP >, and SPxHybridPR< R >.

Referenced by SPxPricer< BP >::setRep().

◆ setPricingTolerance()

virtual void setPricingTolerance ( tol)
virtual

sets pricing tolerance.

Inequality violations are accepted, if their size is less than tol.

Reimplemented in SPxAutoPR< R >, SPxAutoPR< BP >, and SPxHybridPR< R >.

Definition at line 147 of file spxpricer.h.

◆ setRep()

virtual void setRep ( typename SPxSolverBase< R >::Representation  )
virtual

sets basis representation.

Informs pricer about (a change of) the loaded SoPlex's Representation.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxWeightPR< R >, SPxDevexPR< R >, SPxDevexPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, and SPxHybridPR< R >.

Definition at line 181 of file spxpricer.h.

◆ setTolerances()

virtual void setTolerances ( std::shared_ptr< Tolerances newTolerances)
virtual

set the _tolerances member variable

Definition at line 161 of file spxpricer.h.

◆ setType()

virtual void setType ( typename SPxSolverBase< R >::Type  )
virtual

sets pricing type.

Informs pricer about (a change of) the loaded SoPlex's Type. In the sequel, only the corresponding select methods may be called.

Reimplemented in SPxSteepPR< R >, SPxSteepPR< BP >, SPxWeightPR< R >, SPxParMultPR< R >, SPxParMultPR< BP >, SPxDevexPR< R >, SPxDevexPR< BP >, SPxAutoPR< R >, SPxAutoPR< BP >, and SPxHybridPR< R >.

Definition at line 170 of file spxpricer.h.

◆ solver()

virtual SPxSolverBase<R>* solver ( ) const
virtual

returns loaded SPxSolverBase object.

Definition at line 139 of file spxpricer.h.

Referenced by SPxParMultPR< BP >::clone().

Member Data Documentation

◆ _tolerances

std::shared_ptr<Tolerances> _tolerances
protected

tolerances used by the solver

Definition at line 72 of file spxpricer.h.

◆ compare

IdxCompare compare
protected

Definition at line 103 of file spxpricer.h.

◆ m_name

const char* m_name
protected

name of the pricer

Definition at line 64 of file spxpricer.h.

Referenced by SPxPricer< BP >::getName(), and SPxPricer< BP >::operator=().

◆ thesolver

◆ thetolerance

R thetolerance
protected

violation bound

Definition at line 70 of file spxpricer.h.

Referenced by SPxPricer< BP >::operator=(), and SPxPricer< BP >::pricingTolerance().