Weighted start basis.Class SPxWeightST is an implementation of a SPxStarter for generating a Simplex starting basis. Using method setupWeights() it sets up arrays weight and coWeight, or equivalently rowWeight and colWeight. (rowWeight and colWeight are just pointers initialized to weight and coWeight according to the representation of SoPlex base passed to method generate().) More...

#include <spxweightst.h>

Public Member Functions
Construction / destruction
	SPxWeightST ()
	default constructor. More...

	SPxWeightST (const SPxWeightST &old)
	copy constructor More...

SPxWeightST &	operator= (const SPxWeightST &rhs)
	assignment operator More...

virtual	~SPxWeightST ()
	destructor. More...

virtual SPxStarter< R > *	clone () const
	clone function for polymorphism More...

Generation of a start basis
void	generate (SPxSolverBase< R > &base)
	generates start basis for loaded basis. More...

Debugging
virtual bool	isConsistent () const
	consistency check. More...

Public Member Functions inherited from SPxStarter< R >
virtual void	setTolerances (const std::shared_ptr< Tolerances > &tolerances)
	set the tolerances to be used by the starter More...

virtual const std::shared_ptr< Tolerances > &	tolerances () const
	get the toelrances used by the starter More...

virtual const char *	getName () const
	get name of starter. More...

	SPxStarter (const char *name)
	constructor More...

	SPxStarter (const SPxStarter &old)
	copy constructor More...

SPxStarter &	operator= (const SPxStarter &rhs)
	assignment operator More...

virtual	~SPxStarter ()
	destructor. More...

Protected Member Functions
Protected helpers
virtual void	setupWeights (SPxSolverBase< R > &base)
	sets up variable weights. More...

Protected Attributes
Protected data
Array< R >	rowWeight
	weight value for LP rows. More...

Array< R >	colWeight
	weight value for LP columns. More...

DataArray< bool >	rowRight
	set variable to rhs?. More...

DataArray< bool >	colUp
	set primal variable to upper bound. More...

Protected Attributes inherited from SPxStarter< R >
const char *	m_name
	name of the starter More...

std::shared_ptr< Tolerances >	_tolerances
	tolerances for the starter More...

Private Member Functions
Private helpers
void	setPrimalStatus (typename SPxBasisBase< R >::Desc &, const SPxSolverBase< R > &, const SPxId &)

Private Attributes
Private data
DataArray< int >	forbidden

Array< R > *	weight

Array< R > *	coWeight

Detailed Description

template<class R>
class soplex::SPxWeightST< R >

Weighted start basis.

Class SPxWeightST is an implementation of a SPxStarter for generating a Simplex starting basis. Using method setupWeights() it sets up arrays weight and coWeight, or equivalently rowWeight and colWeight. (rowWeight and colWeight are just pointers initialized to weight and coWeight according to the representation of SoPlex base passed to method generate().)

The weight values are then used to setup a starting basis for the LP: vectors with low values are likely to become dual (i.e. basic for a column basis) and such with high values are likely to become primal (i.e. nonbasic for a column basis).

However, if a variable having an upper and lower bound is to become primal, there is still a choice for setting it either to its upper or lower bound. Members rowRight and colUp are used to determine where to set a primal variable. If rowRight[i] is set to a nonzero value, the right-hand side inequality is set tightly for the i 'th to become primal. Analogously, If colUp[j] is nonzero, the j 'th variable will be set to its upper bound if it becomes primal.

Definition at line 66 of file spxweightst.h.

Constructor & Destructor Documentation

◆ SPxWeightST() [1/2]

SPxWeightST ( )

default constructor.

Definition at line 120 of file spxweightst.h.

References SPxWeightST< R >::isConsistent().

Referenced by SPxWeightST< R >::clone().

◆ SPxWeightST() [2/2]

SPxWeightST ( const SPxWeightST< R > & old )

copy constructor

Definition at line 128 of file spxweightst.h.

References SPxWeightST< R >::colWeight, SPxWeightST< R >::isConsistent(), SPxWeightST< R >::rowWeight, and SPxWeightST< R >::weight.

◆ ~SPxWeightST()

virtual ~SPxWeightST ( )

virtual

destructor.

Definition at line 185 of file spxweightst.h.

Member Function Documentation

◆ clone()

virtual SPxStarter<R>* clone ( ) const

virtual

clone function for polymorphism

Implements SPxStarter< R >.

Reimplemented in SPxVectorST< R >, and SPxSumST< R >.

Definition at line 191 of file spxweightst.h.

References SPxWeightST< R >::generate(), SPxWeightST< R >::isConsistent(), and SPxWeightST< R >::SPxWeightST().

◆ generate()

void generate ( SPxSolverBase< R > & base )

virtual

generates start basis for loaded basis.

Implements SPxStarter< R >.

Referenced by SPxWeightST< R >::clone().

◆ isConsistent()

virtual bool isConsistent ( ) const

virtual

consistency check.

Reimplemented from SPxStarter< R >.

Referenced by SPxWeightST< R >::clone(), SPxSumST< R >::operator=(), SPxVectorST< R >::operator=(), SPxWeightST< R >::operator=(), SPxSumST< R >::SPxSumST(), SPxVectorST< R >::SPxVectorST(), and SPxWeightST< R >::SPxWeightST().

◆ operator=()

SPxWeightST& operator= ( const SPxWeightST< R > & rhs )

assignment operator

Definition at line 155 of file spxweightst.h.

References SPxWeightST< R >::colUp, SPxWeightST< R >::colWeight, SPxWeightST< R >::forbidden, SPxWeightST< R >::isConsistent(), SPxStarter< R >::operator=(), SPxWeightST< R >::rowRight, SPxWeightST< R >::rowWeight, and SPxWeightST< R >::weight.

Referenced by SPxVectorST< R >::operator=().

◆ setPrimalStatus()

void setPrimalStatus	(	typename SPxBasisBase< R >::Desc &	,
		const SPxSolverBase< R > &	,
		const SPxId &
	)

private

◆ setupWeights()

virtual void setupWeights ( SPxSolverBase< R > & base )

protectedvirtual

sets up variable weights.

This method is called in order to setup the weights for all variables. It has been declared virtual in order to allow for derived classes to compute other weight values.

Reimplemented in SPxVectorST< R >, and SPxSumST< R >.

Member Data Documentation

◆ colUp

DataArray< bool > colUp

protected

set primal variable to upper bound.

Definition at line 100 of file spxweightst.h.

Referenced by SPxWeightST< R >::operator=().

◆ colWeight

Array< R > colWeight

protected

weight value for LP columns.

Definition at line 96 of file spxweightst.h.

Referenced by SPxWeightST< R >::operator=(), and SPxWeightST< R >::SPxWeightST().

◆ coWeight

Array< R >* coWeight

private

Definition at line 78 of file spxweightst.h.

◆ forbidden

DataArray< int > forbidden

private

Definition at line 74 of file spxweightst.h.

Referenced by SPxWeightST< R >::operator=().

◆ rowRight

DataArray< bool > rowRight

protected

set variable to rhs?.

Definition at line 98 of file spxweightst.h.

Referenced by SPxWeightST< R >::operator=().

◆ rowWeight

Array< R > rowWeight

protected

weight value for LP rows.

Definition at line 94 of file spxweightst.h.

Referenced by SPxWeightST< R >::operator=(), and SPxWeightST< R >::SPxWeightST().

◆ weight

Array< R >* weight

private

Definition at line 76 of file spxweightst.h.

Referenced by SPxWeightST< R >::operator=(), and SPxWeightST< R >::SPxWeightST().

SoPlex

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

template<class R> class soplex::SPxWeightST< R >

Constructor & Destructor Documentation

◆ SPxWeightST() [1/2]

◆ SPxWeightST() [2/2]

◆ ~SPxWeightST()

Member Function Documentation

◆ clone()

◆ generate()

◆ isConsistent()

◆ operator=()

◆ setPrimalStatus()

◆ setupWeights()

Member Data Documentation

◆ colUp

◆ colWeight

◆ coWeight

◆ forbidden

◆ rowRight

◆ rowWeight

◆ weight

template<class R>
class soplex::SPxWeightST< R >