Abstract ratio test base class.Class SPxRatioTester is the virtual base class for computing the ratio test within the Simplex algorithm driven by SoPlex. After a SoPlex solver has been load()ed to an SPxRatioTester, the solver calls selectLeave() for computing the ratio test for the entering simplex and selectEnter() for computing the ratio test in leaving simplex. More...

#include <spxratiotester.h>

Public Member Functions
Access / modification
virtual const char *	getName () const
	get name of ratio tester. More...

virtual void	load (SPxSolverBase< R > *p_solver)
	loads LP. More...

virtual void	clear ()
	unloads LP. More...

virtual SPxSolverBase< R > *	solver () const
	returns loaded LP solver. More...

virtual void	setDelta (R newDelta)
	set allowed bound violation More...

virtual R	getDelta ()
	get allowed bound violation More...

Entering / leaving
virtual int	selectLeave (R &val, R enterTest, bool polish=false)=0
	selects index to leave the basis. More...

virtual SPxId	selectEnter (R &val, int leaveIdx, bool polish=false)=0
	selects variable Id to enter the basis. More...

virtual void	setType (typename SPxSolverBase< R >::Type)
	sets Simplex type. More...

Construction / destruction
	SPxRatioTester (const char *name)
	default constructor More...

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

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

virtual	~SPxRatioTester ()
	destructor. More...

virtual SPxRatioTester *	clone () const =0
	clone function for polymorphism More...

Protected Attributes
Data
SPxSolverBase< R > *	thesolver
	the solver More...

const char *	m_name
	name of the ratio tester More...

SPxSolverBase< R >::Type	m_type
	internal storage of type More...

R	delta
	allowed bound violation More...

Detailed Description

template<class R>
class soplex::SPxRatioTester< R >

Abstract ratio test base class.

Class SPxRatioTester is the virtual base class for computing the ratio test within the Simplex algorithm driven by SoPlex. After a SoPlex solver has been load()ed to an SPxRatioTester, the solver calls selectLeave() for computing the ratio test for the entering simplex and selectEnter() for computing the ratio test in leaving simplex.

Definition at line 41 of file spxratiotester.h.

Constructor & Destructor Documentation

◆ SPxRatioTester() [1/2]

SPxRatioTester ( const char * name )

explicit

default constructor

Definition at line 170 of file spxratiotester.h.

◆ SPxRatioTester() [2/2]

SPxRatioTester ( const SPxRatioTester< R > & old )

copy constructor

Definition at line 177 of file spxratiotester.h.

◆ ~SPxRatioTester()

virtual ~SPxRatioTester ( )

virtual

destructor.

Definition at line 197 of file spxratiotester.h.

References SPxRatioTester< R >::clone().

Member Function Documentation

◆ clear()

virtual void clear ( )

virtual

unloads LP.

Definition at line 77 of file spxratiotester.h.

◆ clone()

virtual SPxRatioTester* clone ( ) const

pure virtual

clone function for polymorphism

Implemented in SPxBoundFlippingRT< R >, SPxFastRT< R >, SPxHarrisRT< R >, and SPxDefaultRT< R >.

Referenced by SPxRatioTester< R >::~SPxRatioTester().

◆ getDelta()

virtual R getDelta ( )

virtual

get allowed bound violation

Reimplemented in SPxFastRT< R >.

Definition at line 98 of file spxratiotester.h.

References SPxRatioTester< R >::delta, SPxRatioTester< R >::selectEnter(), and SPxRatioTester< R >::selectLeave().

◆ getName()

virtual const char* getName ( ) const

virtual

get name of ratio tester.

Definition at line 64 of file spxratiotester.h.

References SPxRatioTester< R >::m_name.

◆ load()

virtual void load ( SPxSolverBase< R > * p_solver )

virtual

loads LP.

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

Reimplemented in SPxFastRT< R >.

Definition at line 71 of file spxratiotester.h.

◆ operator=()

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

assignment operator

Definition at line 184 of file spxratiotester.h.

References SPxRatioTester< R >::delta, SPxRatioTester< R >::m_name, SPxRatioTester< R >::m_type, and SPxRatioTester< R >::thesolver.

Referenced by SPxDefaultRT< R >::operator=(), SPxHarrisRT< R >::operator=(), and SPxFastRT< R >::operator=().

◆ selectEnter()

virtual SPxId selectEnter	(	R &	val,
		int	leaveIdx,
		bool	polish = `false`
	)

pure virtual

selects variable Id to enter the basis.

Method selectEnter() is called by the loaded SoPlex solver, when computing the leaving simplex algorithm. It's task is to select and return the Id of the basis variable that is to enter the basis. When being called, pVec() fullfills the bounds lbBound() and ubBound() within leavetol(). Similarly, coPvec() fulfills the bounds lbBound() and ubBound() within leavetol(). pVec().delta() and coPvec().delta() are the vectors by which pVec() and coPvec() will be updated in this simplex step. Their nonzero indices are stored in sorted order in pVec().idx() and coPvec().idx().

If val > 0, val is the maximum allowed update value for pVec() and coPvec(), otherwise the minimum. Method selectEnter() must chose val of the same sign as passed, such that updating pVec() and coPvec() by val yields a new vector that satisfies all basic bounds (within leavetol). The returned Id must be the Id of an element of pVec() or coPvec(), that reaches one of its bounds with this update.

Implemented in SPxBoundFlippingRT< R >, SPxFastRT< R >, SPxHarrisRT< R >, and SPxDefaultRT< R >.

Referenced by SPxRatioTester< R >::getDelta().

◆ selectLeave()

virtual int selectLeave	(	R &	val,
		R	enterTest,
		bool	polish = `false`
	)

pure virtual

selects index to leave the basis.

Method selectLeave() is called by the loaded SoPlex solver when computing the entering simplex algorithm. Its task is to select and return the index of the basis variable that is to leave the basis. When being called, fVec() fullfills the basic bounds lbBound() and ubBound() within entertol(). fVec().delta() is the vector by which fVec() will be updated in this simplex step. Its nonzero indices are stored in sorted order in fVec().idx().

If val > 0, val is the maximum allowed update value for fVec(), otherwise the minimum. Method selectLeave() must chose val of the same sign as passed, such that updating fVec() by val yields a new vector that satisfies all basic bounds (within entertol). The returned index, must be the index of an element of fVec(), that reaches one of its bounds with this update.

Implemented in SPxBoundFlippingRT< R >, SPxFastRT< R >, SPxHarrisRT< R >, and SPxDefaultRT< R >.

Referenced by SPxRatioTester< R >::getDelta().

◆ setDelta()

virtual void setDelta ( R newDelta )

virtual

set allowed bound violation

Reimplemented in SPxFastRT< R >.

Definition at line 89 of file spxratiotester.h.

References DEFAULT_EPS_ZERO.

◆ setType()

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

virtual

sets Simplex 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 SPxFastRT< R >.

Definition at line 162 of file spxratiotester.h.

◆ solver()

virtual SPxSolverBase<R>* solver ( ) const

virtual

returns loaded LP solver.

Definition at line 83 of file spxratiotester.h.

References SPxRatioTester< R >::thesolver.

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

Member Data Documentation

◆ delta

R delta

protected

allowed bound violation

Definition at line 55 of file spxratiotester.h.

Referenced by SPxRatioTester< R >::getDelta(), SPxRatioTester< R >::operator=(), and SPxFastRT< R >::setDelta().

◆ m_name

const char* m_name

protected

name of the ratio tester

Definition at line 51 of file spxratiotester.h.

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

◆ m_type

SPxSolverBase<R>::Type m_type

protected

internal storage of type

Definition at line 53 of file spxratiotester.h.

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

◆ thesolver

SPxSolverBase<R>* thesolver

protected

the solver

Definition at line 49 of file spxratiotester.h.

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

SoPlex

Public Member Functions

Protected Attributes

Detailed Description

template<class R> class soplex::SPxRatioTester< R >

Constructor & Destructor Documentation

◆ SPxRatioTester() [1/2]

◆ SPxRatioTester() [2/2]

◆ ~SPxRatioTester()

Member Function Documentation

◆ clear()

◆ clone()

◆ getDelta()

◆ getName()

◆ load()

◆ operator=()

◆ selectEnter()

◆ selectLeave()

◆ setDelta()

◆ setType()

◆ solver()

Member Data Documentation

◆ delta

◆ m_name

◆ m_type

◆ thesolver

template<class R>
class soplex::SPxRatioTester< R >