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>

Inheritance diagram for SPxRatioTester:

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

virtual void	load (SPxSolver *p_solver)
	loads LP.

virtual void	clear ()
	unloads LP.

virtual SPxSolver *	solver () const
	returns loaded LP solver.

virtual void	setDelta (Real newDelta)
	set allowed bound violation

virtual Real	getDelta ()
	get allowed bound violation

Entering / leaving
virtual int	selectLeave (Real &val, SPxId enterId)=0
	selects index to leave the basis.

virtual SPxId	selectEnter (Real &val, int leaveIdx)=0
	selects variable Id to enter the basis.

virtual void	setType (SPxSolver::Type)
	sets Simplex type.

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

	SPxRatioTester (const SPxRatioTester &old)
	copy constructor

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

virtual	~SPxRatioTester ()
	destructor.

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

Protected Attributes
Data
SPxSolver *	thesolver
	the solver

const char *	m_name
	name of the ratio tester

SPxSolver::Type	m_type
	internal storage of type

Real	delta
	allowed bound violation

Detailed Description

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 40 of file spxratiotester.h.

Constructor & Destructor Documentation

SPxRatioTester ( const char * name )

explicit

default constructor

Definition at line 169 of file spxratiotester.h.

SPxRatioTester ( const SPxRatioTester & old )

copy constructor

Definition at line 175 of file spxratiotester.h.

virtual ~SPxRatioTester ( )

virtual

destructor.

Definition at line 195 of file spxratiotester.h.

References SPxRatioTester::m_name, and SPxRatioTester::thesolver.

Member Function Documentation

virtual void clear ( )

virtual

unloads LP.

Definition at line 76 of file spxratiotester.h.

References SPxRatioTester::thesolver.

Referenced by SPxSolver::loadLP(), SPxSolver::read(), SPxSolver::reLoad(), SPxSolver::setTester(), and SPxSolver::SPxSolver().

virtual SPxRatioTester* clone ( ) const

pure virtual

clone function for polymorphism

Implemented in SPxBoundFlippingRT, SPxFastRT, SPxHarrisRT, and SPxDefaultRT.

Referenced by SPxSolver::operator=(), and SPxSolver::SPxSolver().

virtual Real getDelta ( )

virtual

get allowed bound violation

Reimplemented in SPxFastRT.

Definition at line 97 of file spxratiotester.h.

References SPxRatioTester::delta.

Referenced by SPxSolver::fpsolve().

virtual const char* getName ( ) const

virtual

get name of ratio tester.

Definition at line 63 of file spxratiotester.h.

References SPxRatioTester::m_name.

Referenced by get_ratio_tester(), and SPxSolver::writeState().

virtual void load ( SPxSolver * p_solver )

virtual

loads LP.

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

Reimplemented in SPxFastRT.

Definition at line 70 of file spxratiotester.h.

References SPxRatioTester::thesolver.

Referenced by SPxSolver::init(), SPxSolver::operator=(), SPxSolver::setTester(), and SPxSolver::SPxSolver().

SPxRatioTester& operator= ( const SPxRatioTester & rhs )

assignment operator

Definition at line 182 of file spxratiotester.h.

References SPxRatioTester::delta, SPxRatioTester::m_name, SPxRatioTester::m_type, and SPxRatioTester::thesolver.

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

virtual SPxId selectEnter	(	Real &	val,
		int	leaveIdx
	)

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, SPxFastRT, SPxHarrisRT, and SPxDefaultRT.

Referenced by SPxSolver::leave().

virtual int selectLeave	(	Real &	val,
		SPxId	enterId
	)

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, SPxFastRT, SPxHarrisRT, and SPxDefaultRT.

Referenced by SPxSolver::enter().

virtual void setDelta ( Real newDelta )

virtual

set allowed bound violation

Reimplemented in SPxFastRT.

Definition at line 88 of file spxratiotester.h.

References DEFAULT_EPS_ZERO, and SPxRatioTester::delta.

Referenced by SPxSolver::fpsolve(), and SPxSolver::init().

virtual void setType ( SPxSolver::Type )

virtual

sets Simplex type.