#include <itkParticleSwarmOptimizerBase.h>

Inheritance diagram for itk::ParticleSwarmOptimizerBase:

Collaboration diagram for itk::ParticleSwarmOptimizerBase:

Detailed Description

Abstract implementation of a Particle Swarm Optimization (PSO) algorithm.

The PSO algorithm was originally presented in:
J. Kennedy, R. Eberhart, "Particle Swarm Optimization", Proc. IEEE Int. Neural Networks, 1995.

The algorithm is a stochastic global search optimization approach. Optimization is performed by maintaining a swarm of particles that traverse the parameter space, searching for the optimal function value. Associated with each particle are its location and speed, in parameter space.

Swarm initialization is performed within the user supplied parameter bounds using either a uniform distribution or a normal distribution centered on the initial parameter values supplied by the user. The search terminates when the maximal number of iterations has been reached or when the change in the best value in the past $g$ generations is below a threshold and the swarm has collapsed (i.e. best personal particle locations are close to the swarm's best location in parameter space).

The actual optimization procedure, updating the swarm, is performed in the subclasses, required to implement the UpdateSwarm() method.

NOTE: This implementation only performs minimization.

Definition at line 56 of file itkParticleSwarmOptimizerBase.h.

Classes
struct	ParticleData

Public Types
using	ConstPointer = SmartPointer< const Self >

using	MeasureType = CostFunctionType::MeasureType

using	NumberOfGenerationsType = unsigned int

using	NumberOfIterationsType = unsigned int

using	NumberOfParticlesType = unsigned int

using	ParameterBoundsType = std::vector< std::pair< ParametersType::ValueType, ParametersType::ValueType > >

using	Pointer = SmartPointer< Self >

using	RandomVariateGeneratorType = Statistics::MersenneTwisterRandomVariateGenerator

using	Self = ParticleSwarmOptimizerBase

using	Superclass = SingleValuedNonLinearOptimizer

using	SwarmType = std::vector< ParticleData >

using	ValueType = ParametersType::ValueType

Public Types inherited from itk::SingleValuedNonLinearOptimizer
using	ConstPointer = SmartPointer< const Self >

using	CostFunctionPointer = CostFunctionType::Pointer

using	CostFunctionType = SingleValuedCostFunction

using	DerivativeType = CostFunctionType::DerivativeType

using	MeasureType = CostFunctionType::MeasureType

using	ParametersType = Superclass::ParametersType

using	Pointer = SmartPointer< Self >

using	Self = SingleValuedNonLinearOptimizer

using	Superclass = NonLinearOptimizer

Public Types inherited from itk::NonLinearOptimizer
using	ConstPointer = SmartPointer< const Self >

using	ParametersType = Superclass::ParametersType

using	Pointer = SmartPointer< Self >

using	ScalesType = Superclass::ScalesType

using	Self = NonLinearOptimizer

using	Superclass = Optimizer

Public Types inherited from itk::Optimizer
using	ConstPointer = SmartPointer< const Self >

using	ParametersType = OptimizerParameters< double >

using	Pointer = SmartPointer< Self >

using	ScalesType = Array< double >

using	Self = Optimizer

using	Superclass = Object

Public Types inherited from itk::Object
using	ConstPointer = SmartPointer< const Self >

using	Pointer = SmartPointer< Self >

using	Self = Object

using	Superclass = LightObject

Public Types inherited from itk::LightObject
using	ConstPointer = SmartPointer< const Self >

using	Pointer = SmartPointer< Self >

using	Self = LightObject

Public Member Functions
virtual MeasureType	GetFunctionConvergenceTolerance ()

virtual bool	GetInitializeNormalDistribution ()

virtual NumberOfIterationsType	GetMaximalNumberOfIterations ()

virtual const char *	GetNameOfClass () const

virtual NumberOfGenerationsType	GetNumberOfGenerationsWithMinimalImprovement ()

virtual NumberOfParticlesType	GetNumberOfParticles ()

ParameterBoundsType	GetParameterBounds () const

virtual ParametersType	GetParametersConvergenceTolerance ()

virtual double	GetPercentageParticlesConverged ()

virtual bool	GetPrintSwarm ()

virtual RandomVariateGeneratorType::IntegerType	GetSeed ()

const std::string	GetStopConditionDescription () const override

virtual bool	GetUseSeed ()

MeasureType	GetValue () const

virtual void	InitializeNormalDistributionOff ()

virtual void	InitializeNormalDistributionOn ()

void	PrintSwarm (std::ostream &os, Indent indent) const

virtual void	PrintSwarmOff ()

virtual void	PrintSwarmOn ()

virtual void	SetFunctionConvergenceTolerance (MeasureType _arg)

virtual void	SetInitializeNormalDistribution (bool _arg)

virtual void	SetMaximalNumberOfIterations (NumberOfIterationsType _arg)

virtual void	SetNumberOfGenerationsWithMinimalImprovement (NumberOfGenerationsType _arg)

void	SetNumberOfParticles (NumberOfParticlesType n)

void	SetParametersConvergenceTolerance (ValueType convergenceTolerance, unsigned int sz)

virtual void	SetParametersConvergenceTolerance (ParametersType _arg)

virtual void	SetPercentageParticlesConverged (double _arg)

virtual void	SetPrintSwarm (bool _arg)

virtual void	SetSeed (RandomVariateGeneratorType::IntegerType _arg)

virtual void	SetUseSeed (bool _arg)

void	StartOptimization () override

virtual void	UseSeedOff ()

virtual void	UseSeedOn ()


void	SetInitialSwarm (const SwarmType &initialSwarm)

void	ClearSwarm ()


virtual void	SetParameterBounds (ParameterBoundsType &bounds)

void	SetParameterBounds (std::pair< ParametersType::ValueType, ParametersType::ValueType > &bounds, unsigned int n)

Public Member Functions inherited from itk::SingleValuedNonLinearOptimizer
virtual ::itk::LightObject::Pointer	CreateAnother () const

virtual const CostFunctionType *	GetCostFunction () const

virtual CostFunctionType *	GetModifiableCostFunction ()

MeasureType	GetValue (const ParametersType &parameters) const

virtual void	SetCostFunction (CostFunctionType *costFunction)

Public Member Functions inherited from itk::Optimizer
virtual const ParametersType &	GetCurrentPosition () const

virtual const ParametersType &	GetInitialPosition () const

virtual void	SetInitialPosition (const ParametersType &param)

void	SetScales (const ScalesType &scales)

virtual const ScalesType &	GetScales () const

virtual const ScalesType &	GetInverseScales () const

Public Member Functions inherited from itk::Object
unsigned long	AddObserver (const EventObject &event, Command *)

unsigned long	AddObserver (const EventObject &event, Command *) const

virtual void	DebugOff () const

virtual void	DebugOn () const

Command *	GetCommand (unsigned long tag)

bool	GetDebug () const

MetaDataDictionary &	GetMetaDataDictionary ()

const MetaDataDictionary &	GetMetaDataDictionary () const

virtual ModifiedTimeType	GetMTime () const

virtual const TimeStamp &	GetTimeStamp () const

bool	HasObserver (const EventObject &event) const

void	InvokeEvent (const EventObject &)

void	InvokeEvent (const EventObject &) const

virtual void	Modified () const

void	Register () const override

void	RemoveAllObservers ()

void	RemoveObserver (unsigned long tag)

void	SetDebug (bool debugFlag) const

void	SetReferenceCount (int) override

void	UnRegister () const noexceptoverride

void	SetMetaDataDictionary (const MetaDataDictionary &rhs)

void	SetMetaDataDictionary (MetaDataDictionary &&rrhs)

virtual void	SetObjectName (std::string _arg)

virtual const std::string &	GetObjectName () const

Public Member Functions inherited from itk::LightObject
virtual void	Delete ()

virtual int	GetReferenceCount () const

	itkCloneMacro (Self)

void	Print (std::ostream &os, Indent indent=0) const

Protected Member Functions
void	FileInitialization ()

virtual void	Initialize ()

	ParticleSwarmOptimizerBase ()

void	PrintParamtersType (const ParametersType &x, std::ostream &os) const

void	PrintSelf (std::ostream &os, Indent indent) const override

void	RandomInitialization ()

virtual void	UpdateSwarm ()=0

virtual void	ValidateSettings ()

	~ParticleSwarmOptimizerBase () override

Protected Member Functions inherited from itk::SingleValuedNonLinearOptimizer
void	PrintSelf (std::ostream &os, Indent indent) const override

	SingleValuedNonLinearOptimizer ()

	~SingleValuedNonLinearOptimizer () override=default

Protected Member Functions inherited from itk::NonLinearOptimizer
	NonLinearOptimizer ()=default

	~NonLinearOptimizer () override

Protected Member Functions inherited from itk::Optimizer
	Optimizer ()

virtual void	SetCurrentPosition (const ParametersType &param)

	~Optimizer () override=default

Protected Member Functions inherited from itk::Object
	Object ()

bool	PrintObservers (std::ostream &os, Indent indent) const

virtual void	SetTimeStamp (const TimeStamp &time)

	~Object () override

Protected Member Functions inherited from itk::LightObject
virtual LightObject::Pointer	InternalClone () const

	LightObject ()

virtual void	PrintHeader (std::ostream &os, Indent indent) const

virtual void	PrintTrailer (std::ostream &os, Indent indent) const

virtual	~LightObject ()

Protected Attributes
CostFunctionType::MeasureType	m_FunctionBestValue {0}

std::vector< MeasureType >	m_FunctionBestValueMemory

CostFunctionType::MeasureType	m_FunctionConvergenceTolerance

bool	m_InitializeNormalDistribution

NumberOfIterationsType	m_IterationIndex {0}

NumberOfIterationsType	m_MaximalNumberOfIterations

NumberOfGenerationsType	m_NumberOfGenerationsWithMinimalImprovement

NumberOfParticlesType	m_NumberOfParticles

ParameterBoundsType	m_ParameterBounds

ParametersType	m_ParametersBestValue

ParametersType	m_ParametersConvergenceTolerance

std::vector< ParticleData >	m_Particles

double	m_PercentageParticlesConverged

bool	m_PrintSwarm

RandomVariateGeneratorType::IntegerType	m_Seed

std::ostringstream	m_StopConditionDescription

bool	m_UseSeed

Protected Attributes inherited from itk::SingleValuedNonLinearOptimizer
CostFunctionPointer	m_CostFunction

Protected Attributes inherited from itk::Optimizer
ParametersType	m_CurrentPosition

bool	m_ScalesInitialized { false }

Protected Attributes inherited from itk::LightObject
std::atomic< int >	m_ReferenceCount

Additional Inherited Members
Static Public Member Functions inherited from itk::SingleValuedNonLinearOptimizer
static Pointer	New ()

Static Public Member Functions inherited from itk::NonLinearOptimizer
static Pointer	New ()

Static Public Member Functions inherited from itk::Optimizer
static Pointer	New ()

Static Public Member Functions inherited from itk::Object
static bool	GetGlobalWarningDisplay ()

static void	GlobalWarningDisplayOff ()

static void	GlobalWarningDisplayOn ()

static Pointer	New ()

static void	SetGlobalWarningDisplay (bool flag)

Static Public Member Functions inherited from itk::LightObject
static void	BreakOnError ()

static Pointer	New ()

Member Typedef Documentation

using itk::ParticleSwarmOptimizerBase::ConstPointer = SmartPointer<const Self>

Definition at line 66 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::MeasureType = CostFunctionType::MeasureType

Definition at line 87 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::NumberOfGenerationsType = unsigned int

Definition at line 86 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::NumberOfIterationsType = unsigned int

Definition at line 84 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::NumberOfParticlesType = unsigned int

Definition at line 85 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::ParameterBoundsType = std::vector< std::pair<ParametersType::ValueType, ParametersType::ValueType> >

Examples:: Examples/IO/XML/itkParticleSwarmOptimizerDOMReader.cxx, and Examples/IO/XML/itkParticleSwarmOptimizerSAXReader.cxx.

Definition at line 72 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::Pointer = SmartPointer<Self>

Definition at line 65 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::RandomVariateGeneratorType = Statistics::MersenneTwisterRandomVariateGenerator

Definition at line 89 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::Self = ParticleSwarmOptimizerBase

Standard "Self" type alias.

Definition at line 63 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::Superclass = SingleValuedNonLinearOptimizer

Definition at line 64 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::SwarmType = std::vector<ParticleData>

Definition at line 83 of file itkParticleSwarmOptimizerBase.h.

using itk::ParticleSwarmOptimizerBase::ValueType = ParametersType::ValueType

Definition at line 88 of file itkParticleSwarmOptimizerBase.h.

Constructor & Destructor Documentation

itk::ParticleSwarmOptimizerBase::ParticleSwarmOptimizerBase ( )

protected

itk::ParticleSwarmOptimizerBase::~ParticleSwarmOptimizerBase ( )

overrideprotected

Member Function Documentation

void itk::ParticleSwarmOptimizerBase::ClearSwarm ( )

Specify the initial swarm. Useful for evaluating PSO variants. If the initial swarm is set it will be used. To revert to random initialization (uniform or normal particle distributions) set using an empty swarm.

void itk::ParticleSwarmOptimizerBase::FileInitialization ( )

protected

virtual MeasureType itk::ParticleSwarmOptimizerBase::GetFunctionConvergenceTolerance ( )

virtual

virtual bool itk::ParticleSwarmOptimizerBase::GetInitializeNormalDistribution ( )

virtual

virtual NumberOfIterationsType itk::ParticleSwarmOptimizerBase::GetMaximalNumberOfIterations ( )

virtual

virtual const char* itk::ParticleSwarmOptimizerBase::GetNameOfClass ( ) const

virtual

Run-time type information (and related methods).

Reimplemented from itk::SingleValuedNonLinearOptimizer.

Reimplemented in itk::InitializationBiasedParticleSwarmOptimizer, and itk::ParticleSwarmOptimizer.

virtual NumberOfGenerationsType itk::ParticleSwarmOptimizerBase::GetNumberOfGenerationsWithMinimalImprovement ( )

virtual

virtual NumberOfParticlesType itk::ParticleSwarmOptimizerBase::GetNumberOfParticles ( )

virtual

ParameterBoundsType itk::ParticleSwarmOptimizerBase::GetParameterBounds ( ) const

virtual ParametersType itk::ParticleSwarmOptimizerBase::GetParametersConvergenceTolerance ( )

virtual

virtual double itk::ParticleSwarmOptimizerBase::GetPercentageParticlesConverged ( )

virtual

virtual bool itk::ParticleSwarmOptimizerBase::GetPrintSwarm ( )

virtual

virtual RandomVariateGeneratorType::IntegerType itk::ParticleSwarmOptimizerBase::GetSeed ( )

virtual

const std::string itk::ParticleSwarmOptimizerBase::GetStopConditionDescription ( ) const

overridevirtual

Get the reason for termination

Reimplemented from itk::Optimizer.

virtual bool itk::ParticleSwarmOptimizerBase::GetUseSeed ( )

virtual

MeasureType itk::ParticleSwarmOptimizerBase::GetValue ( ) const

Get the function value for the current position. NOTE: This value is only valid during and after the execution of the StartOptimization() method.

virtual void itk::ParticleSwarmOptimizerBase::Initialize ( )

protectedvirtual

Initialize the particle swarm, and seed the random number generator.

virtual void itk::ParticleSwarmOptimizerBase::InitializeNormalDistributionOff ( )

virtual

virtual void itk::ParticleSwarmOptimizerBase::InitializeNormalDistributionOn ( )

virtual

void itk::ParticleSwarmOptimizerBase::PrintParamtersType	(	const ParametersType &	x,
		std::ostream &	os
	)		const

protected

void itk::ParticleSwarmOptimizerBase::PrintSelf	(	std::ostream &	os,
		Indent	indent
	)		const

overrideprotectedvirtual

Methods invoked by Print() to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from itk::Optimizer.

void itk::ParticleSwarmOptimizerBase::PrintSwarm	(	std::ostream &	os,
		Indent	indent
	)		const

Print the swarm information to the given output stream. Each line (particle data) is of the form: current_parameters current_velocity current_value best_parameters best_value

virtual void itk::ParticleSwarmOptimizerBase::PrintSwarmOff ( )

virtual

virtual void itk::ParticleSwarmOptimizerBase::PrintSwarmOn ( )

virtual

void itk::ParticleSwarmOptimizerBase::RandomInitialization ( )

protected

virtual void itk::ParticleSwarmOptimizerBase::SetFunctionConvergenceTolerance ( MeasureType _arg )

virtual

The optimization algorithm will terminate when the function improvement in the last m_NumberOfGenerationsWithMinimalImprovement generations is less than m_FunctionConvergenceTolerance and the maximal distance between particles and the best particle in each dimension is less than m_ParametersConvergenceTolerance[i] for the specified percentage of the particles. That is, we haven't improved the best function value for a while and in the parameter space most (m%) of our particles attained their best value close to the swarm's best value. NOTE: The use of different tolerances for each dimension is desired when optimizing over non-commensurate parameters (e.g. rotation and translation). Alternatively, we could use ITK's parameter scaling approach. The current approach seems more intuitive.

virtual void itk::ParticleSwarmOptimizerBase::SetInitializeNormalDistribution ( bool _arg )

virtual

Specify whether to initialize the particles using a normal distribution centered on the user supplied initial value or a uniform distribution. If the optimum is expected to be near the initial value it is likely that initializing with a normal distribution will result in faster convergence.

void itk::ParticleSwarmOptimizerBase::SetInitialSwarm ( const SwarmType & initialSwarm )

Specify the initial swarm. Useful for evaluating PSO variants. If the initial swarm is set it will be used. To revert to random initialization (uniform or normal particle distributions) set using an empty swarm.

virtual void itk::ParticleSwarmOptimizerBase::SetMaximalNumberOfIterations ( NumberOfIterationsType _arg )

virtual

Set/Get maximal number of iterations - the maximal number of function evaluations is m_MaximalNumberOfIterations*m_NumberOfParticles

virtual void itk::ParticleSwarmOptimizerBase::SetNumberOfGenerationsWithMinimalImprovement ( NumberOfGenerationsType _arg )

virtual

Set/Get the number of generations to continue with minimal improvement in the function value, |f_best(g_i) - f_best(g_k)|<threshold where k <= i+NumberOfGenerationsWithMinimalImprovement Minimal value is one.

void itk::ParticleSwarmOptimizerBase::SetNumberOfParticles ( NumberOfParticlesType n )

Set/Get number of particles in the swarm - the maximal number of function evaluations is m_MaximalNumberOfIterations*m_NumberOfParticles

virtual void itk::ParticleSwarmOptimizerBase::SetParameterBounds ( ParameterBoundsType & bounds )

virtual

Set/Get the parameter bounds. Search for optimal value is inside these bounds. NOTE: It is assumed that the first entry is the minimal value, second is the maximal value.

void itk::ParticleSwarmOptimizerBase::SetParameterBounds	(	std::pair< ParametersType::ValueType, ParametersType::ValueType > &	bounds,
		unsigned int	n
	)

Set/Get the parameter bounds. Search for optimal value is inside these bounds. NOTE: It is assumed that the first entry is the minimal value, second is the maximal value.

void itk::ParticleSwarmOptimizerBase::SetParametersConvergenceTolerance	(	ValueType	convergenceTolerance,
		unsigned int	sz
	)

Set parameters convergence tolerance using the same value for all, sz, parameters

virtual void itk::ParticleSwarmOptimizerBase::SetParametersConvergenceTolerance ( ParametersType _arg )

virtual

virtual void itk::ParticleSwarmOptimizerBase::SetPercentageParticlesConverged ( double _arg )

virtual

virtual void itk::ParticleSwarmOptimizerBase::SetPrintSwarm ( bool _arg )

virtual

Indicate whether or not to output the swarm information when printing an object. By default this option is turned off as it generates too much information.

virtual void itk::ParticleSwarmOptimizerBase::SetSeed ( RandomVariateGeneratorType::IntegerType _arg )

virtual

Set the random number seed for the swarm. Use this method to produce reaptible results, typically, for testing.

virtual void itk::ParticleSwarmOptimizerBase::SetUseSeed ( bool _arg )

virtual

Use a specific seed to initialize the random number generator. If On, use m_Seed to seed the random number generator. Default is Off.

void itk::ParticleSwarmOptimizerBase::StartOptimization ( )

overridevirtual

Start optimization.

Reimplemented from itk::Optimizer.

virtual void itk::ParticleSwarmOptimizerBase::UpdateSwarm ( )

protectedpure virtual