Idiot Class Reference

This class implements a very silly algorithm. More...

#include <Idiot.hpp>

Collaboration diagram for Idiot:

Public Member Functions
void	solve2 (CoinMessageHandler handler, const CoinMessages messages)
	Stuff for internal use.
Constructors and destructor
Just a pointer to model is kept
	Idiot ()
	Default constructor.
	Idiot (OsiSolverInterface &model)
	Constructor with model.
	Idiot (const Idiot &)
	Copy constructor.
Idiot &	operator= (const Idiot &rhs)
	Assignment operator. This copies the data.
	~Idiot ()
	Destructor.
Algorithmic calls

void	solve ()
	Get an approximate solution with the idiot code.
void	crash (int numberPass, CoinMessageHandler handler, const CoinMessages messages)
	Lightweight "crash".
void	crossOver (int mode)
	Use simplex to get an optimal solution mode is how many steps the simplex crossover should take to arrive to an extreme point: 0 - chosen,all ever used, all 1 - chosen, all 2 - all 3 - do not do anything - maybe basis + 16 do presolves.
Gets and sets of most useful data

double	getStartingWeight () const
	Starting weight - small emphasizes feasibility, default 1.0e-4.
void	setStartingWeight (double value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
double	getWeightFactor () const
	Weight factor - weight multiplied by this when changes, default 0.333.
void	setWeightFactor (double value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
double	getFeasibilityTolerance () const
	Feasibility tolerance - problem essentially feasible if individual infeasibilities less than this.
void	setFeasibilityTolerance (double value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
double	getReasonablyFeasible () const
	Reasonably feasible.
void	setReasonablyFeasible (double value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
double	getExitInfeasibility () const
	Exit infeasibility - exit if sum of infeasibilities less than this.
void	setExitInfeasibility (double value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
int	getMajorIterations () const
	Major iterations.
void	setMajorIterations (int value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
int	getMinorIterations () const
	Minor iterations.
void	setMinorIterations (int value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
int	getMinorIterations0 () const
	Starting weight - small emphasizes feasibility, default 1.0e-4.
void	setMinorIterations0 (int value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
int	getReduceIterations () const
	Reduce weight after this many major iterations.
void	setReduceIterations (int value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
int	getLogLevel () const
	Amount of information - default of 1 should be okay.
void	setLogLevel (int value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
int	getLightweight () const
	How lightweight - 0 not, 1 yes, 2 very lightweight.
void	setLightweight (int value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
int	getStrategy () const
	strategy
void	setStrategy (int value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
double	getDropEnoughFeasibility () const
	Fine tuning - okay if feasibility drop this factor.
void	setDropEnoughFeasibility (double value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
double	getDropEnoughWeighted () const
	Fine tuning - okay if weighted obj drop this factor.
void	setDropEnoughWeighted (double value)
	Starting weight - small emphasizes feasibility, default 1.0e-4.
Private Member Functions
IdiotResult	IdiSolve (int nrows, int ncols, double rowsol, double colsol, double pi, double djs, const double origcost, double rowlower, double rowupper, const double lower, const double upper, const double element, const int row, const CoinBigIndex colcc, const int length, double lambda, int maxIts, double mu, double drop, double maxmin, double offset, int strategy, double djTol, double djExit, double djFlag, CoinThreadRandom *randomNumberGenerator)
int	dropping (IdiotResult result, double tolerance, double small, int *nbad)
IdiotResult	objval (int nrows, int ncols, double rowsol, double colsol, double pi, double djs, const double cost, const double rowlower, const double rowupper, const double lower, const double upper, const double elemnt, const int row, const CoinBigIndex columnStart, const int length, int extraBlock, int rowExtra, double solExtra, double elemExtra, double upperExtra, double costExtra, double weight)
int	cleanIteration (int iteration, int ordinaryStart, int ordinaryEnd, double colsol, const double lower, const double upper, const double rowLower, const double rowUpper, const double cost, const double *element, double fixTolerance, double &objChange, double &infChange)
Private Attributes
OsiSolverInterface *	model_
	Underlying model.
double	djTolerance_
double	mu_
double	drop_
double	muFactor_
double	stopMu_
double	smallInfeas_
double	reasonableInfeas_
double	exitDrop_
double	muAtExit_
double	exitFeasibility_
double	dropEnoughFeasibility_
double	dropEnoughWeighted_
int *	whenUsed_
int	maxBigIts_
int	maxIts_
int	majorIterations_
int	logLevel_
int	logFreq_
int	checkFrequency_
int	lambdaIterations_
int	maxIts2_
int	strategy_
int	lightWeight_

Detailed Description

This class implements a very silly algorithm.

It has no merit apart from the fact that it gets an approximate solution to some classes of problems. Better if vaguely homogeneous. It works on problems where volume algorithm works and often gets a better primal solution but it has no dual solution.

It can also be used as a "crash" to get a problem started. This is probably its most useful function.

It is based on the idea that algorithms with terrible convergence properties may be okay at first. Throw in some random dubious tricks and the resulting code may be worth keeping as long as you don't look at it.

Definition at line 45 of file Idiot.hpp.

Constructor & Destructor Documentation

Idiot::Idiot ( )

Default constructor.

Idiot::Idiot ( OsiSolverInterface & model )

Constructor with model.

Idiot::Idiot ( const Idiot & )

Copy constructor.

Idiot::~Idiot ( )

Destructor.

Member Function Documentation

Idiot& Idiot::operator= ( const Idiot & rhs )

Assignment operator. This copies the data.

void Idiot::solve ( )

Get an approximate solution with the idiot code.

void Idiot::crash	(	int	numberPass,
		CoinMessageHandler *	handler,
		const CoinMessages *	messages
	)

Lightweight "crash".

void Idiot::crossOver ( int mode )

Use simplex to get an optimal solution mode is how many steps the simplex crossover should take to arrive to an extreme point: 0 - chosen,all ever used, all 1 - chosen, all 2 - all 3 - do not do anything - maybe basis + 16 do presolves.

double Idiot::getStartingWeight ( ) const [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 92 of file Idiot.hpp.

void Idiot::setStartingWeight ( double value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 94 of file Idiot.hpp.

double Idiot::getWeightFactor ( ) const [inline]

Weight factor - weight multiplied by this when changes, default 0.333.

Definition at line 98 of file Idiot.hpp.

void Idiot::setWeightFactor ( double value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 100 of file Idiot.hpp.

double Idiot::getFeasibilityTolerance ( ) const [inline]

Feasibility tolerance - problem essentially feasible if individual infeasibilities less than this.

default 0.1

Definition at line 105 of file Idiot.hpp.

void Idiot::setFeasibilityTolerance ( double value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 107 of file Idiot.hpp.

double Idiot::getReasonablyFeasible ( ) const [inline]

Reasonably feasible.

Dubious method concentrates more on objective when sum of infeasibilities less than this. Very dubious default value of (Number of rows)/20

Definition at line 112 of file Idiot.hpp.

void Idiot::setReasonablyFeasible ( double value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 114 of file Idiot.hpp.

double Idiot::getExitInfeasibility ( ) const [inline]

Exit infeasibility - exit if sum of infeasibilities less than this.

Default -1.0 (i.e. switched off)

Definition at line 118 of file Idiot.hpp.

void Idiot::setExitInfeasibility ( double value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 120 of file Idiot.hpp.

int Idiot::getMajorIterations ( ) const [inline]

Major iterations.

stop after this number. Default 30. Use 2-5 for "crash" 50-100 for serious crunching

Definition at line 124 of file Idiot.hpp.

void Idiot::setMajorIterations ( int value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 126 of file Idiot.hpp.

int Idiot::getMinorIterations ( ) const [inline]

Minor iterations.

Do this number of tiny steps before deciding whether to change weights etc. Default - dubious sqrt(Number of Rows). Good numbers 105 to 405 say (5 is dubious method of making sure idiot is not trying to be clever which it may do every 10 minor iterations)

Definition at line 134 of file Idiot.hpp.

void Idiot::setMinorIterations ( int value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 136 of file Idiot.hpp.

int Idiot::getMinorIterations0 ( ) const [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 139 of file Idiot.hpp.

void Idiot::setMinorIterations0 ( int value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 141 of file Idiot.hpp.

int Idiot::getReduceIterations ( ) const [inline]

Reduce weight after this many major iterations.

It may get reduced before this but this is a maximum. Default 3. 3-10 plausible.

Definition at line 146 of file Idiot.hpp.

void Idiot::setReduceIterations ( int value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 148 of file Idiot.hpp.

int Idiot::getLogLevel ( ) const [inline]

Amount of information - default of 1 should be okay.

Definition at line 151 of file Idiot.hpp.

void Idiot::setLogLevel ( int value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 153 of file Idiot.hpp.

int Idiot::getLightweight ( ) const [inline]

How lightweight - 0 not, 1 yes, 2 very lightweight.

Definition at line 156 of file Idiot.hpp.

void Idiot::setLightweight ( int value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 158 of file Idiot.hpp.

int Idiot::getStrategy ( ) const [inline]

strategy

Definition at line 161 of file Idiot.hpp.

void Idiot::setStrategy ( int value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 163 of file Idiot.hpp.

double Idiot::getDropEnoughFeasibility ( ) const [inline]

Fine tuning - okay if feasibility drop this factor.

Definition at line 166 of file Idiot.hpp.

void Idiot::setDropEnoughFeasibility ( double value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 168 of file Idiot.hpp.

double Idiot::getDropEnoughWeighted ( ) const [inline]

Fine tuning - okay if weighted obj drop this factor.

Definition at line 171 of file Idiot.hpp.

void Idiot::setDropEnoughWeighted ( double value ) [inline]

Starting weight - small emphasizes feasibility, default 1.0e-4.

Definition at line 173 of file Idiot.hpp.

void Idiot::solve2	(	CoinMessageHandler *	handler,
		const CoinMessages *	messages
	)

Stuff for internal use.

Does actual work

IdiotResult Idiot::IdiSolve	(	int	nrows,
		int	ncols,
		double *	rowsol,
		double *	colsol,
		double *	pi,
		double *	djs,
		const double *	origcost,
		double *	rowlower,
		double *	rowupper,
		const double *	lower,
		const double *	upper,
		const double *	element,
		const int *	row,
		const CoinBigIndex *	colcc,
		const int *	length,
		double *	lambda,
		int	maxIts,
		double	mu,
		double	drop,
		double	maxmin,
		double	offset,
		int	strategy,
		double	djTol,
		double	djExit,
		double	djFlag,
		CoinThreadRandom *	randomNumberGenerator
	)			`[private]`

int Idiot::dropping	(	IdiotResult	result,
		double	tolerance,
		double	small,
		int *	nbad
	)			`[private]`

IdiotResult Idiot::objval	(	int	nrows,
		int	ncols,
		double *	rowsol,
		double *	colsol,
		double *	pi,
		double *	djs,
		const double *	cost,
		const double *	rowlower,
		const double *	rowupper,
		const double *	lower,
		const double *	upper,
		const double *	elemnt,
		const int *	row,
		const CoinBigIndex *	columnStart,
		const int *	length,
		int	extraBlock,
		int *	rowExtra,
		double *	solExtra,
		double *	elemExtra,
		double *	upperExtra,
		double *	costExtra,
		double	weight
	)			`[private]`

int Idiot::cleanIteration	(	int	iteration,
		int	ordinaryStart,
		int	ordinaryEnd,
		double *	colsol,
		const double *	lower,
		const double *	upper,
		const double *	rowLower,
		const double *	rowUpper,
		const double *	cost,
		const double *	element,
		double	fixTolerance,
		double &	objChange,
		double &	infChange
	)			`[private]`