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itk::ParticleSwarmOptimizerBase Class Referenceabstract

#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 55 of file itkParticleSwarmOptimizerBase.h.


struct  ParticleData

Public Types

typedef SmartPointer< const SelfConstPointer
typedef unsigned int NumberOfGenerationsType
typedef unsigned int NumberOfIterationsType
typedef unsigned int NumberOfParticlesType
typedef std::vector< std::pair
< ParametersType::ValueType,
ParametersType::ValueType > > 
typedef SmartPointer< SelfPointer
typedef ParticleSwarmOptimizerBase Self
typedef std::vector< ParticleDataSwarmType
typedef ParametersType::ValueType ValueType
- Public Types inherited from itk::SingleValuedNonLinearOptimizer
typedef SmartPointer< const SelfConstPointer
typedef CostFunctionType::Pointer CostFunctionPointer
typedef SingleValuedCostFunction CostFunctionType
typedef Superclass::ParametersType ParametersType
typedef SmartPointer< SelfPointer
typedef NonLinearOptimizer Superclass
- Public Types inherited from itk::NonLinearOptimizer
typedef SmartPointer< const SelfConstPointer
typedef Superclass::ParametersType ParametersType
typedef SmartPointer< SelfPointer
typedef Superclass::ScalesType ScalesType
typedef NonLinearOptimizer Self
typedef Optimizer Superclass
- Public Types inherited from itk::Optimizer
typedef SmartPointer< const SelfConstPointer
typedef OptimizerParameters
< double > 
typedef SmartPointer< SelfPointer
typedef Array< double > ScalesType
typedef Optimizer Self
typedef Object Superclass
- Public Types inherited from itk::Object
typedef SmartPointer< const SelfConstPointer
typedef SmartPointer< SelfPointer
typedef Object Self
typedef LightObject Superclass
- Public Types inherited from itk::LightObject
typedef SmartPointer< const SelfConstPointer
typedef SmartPointer< SelfPointer
typedef LightObject Self

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 ()
GetSeed ()
virtual const std::string GetStopConditionDescription () const
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 (void)
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 (void) const
virtual const CostFunctionTypeGetCostFunction () const
virtual CostFunctionTypeGetModifiableCostFunction ()
MeasureType GetValue (const ParametersType &parameters) const
virtual void SetCostFunction (CostFunctionType *costFunction)

Protected Member Functions

void FileInitialization ()
virtual void Initialize ()
void operator= (const Self &)
 ParticleSwarmOptimizerBase ()
 ParticleSwarmOptimizerBase (const Self &)
void PrintParamtersType (const ParametersType &x, std::ostream &os) const
void PrintSelf (std::ostream &os, Indent indent) const
void RandomInitialization ()
virtual void UpdateSwarm ()=0
virtual void ValidateSettings ()
virtual ~ParticleSwarmOptimizerBase ()
- Protected Member Functions inherited from itk::SingleValuedNonLinearOptimizer
void PrintSelf (std::ostream &os, Indent indent) const
 SingleValuedNonLinearOptimizer ()
virtual ~SingleValuedNonLinearOptimizer ()
- Protected Member Functions inherited from itk::NonLinearOptimizer
 NonLinearOptimizer ()
virtual ~NonLinearOptimizer ()
- Protected Member Functions inherited from itk::Optimizer
 Optimizer ()
virtual void SetCurrentPosition (const ParametersType &param)
virtual ~Optimizer ()
- Protected Member Functions inherited from itk::Object
 Object ()
bool PrintObservers (std::ostream &os, Indent indent) const
virtual void SetTimeStamp (const TimeStamp &time)
virtual ~Object ()
- 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
std::vector< MeasureTypem_FunctionBestValueMemory
CostFunctionType::MeasureType m_FunctionConvergenceTolerance
bool m_InitializeNormalDistribution
NumberOfIterationsType m_IterationIndex
NumberOfIterationsType m_MaximalNumberOfIterations
NumberOfGenerationsType m_NumberOfGenerationsWithMinimalImprovement
NumberOfParticlesType m_NumberOfParticles
ParameterBoundsType m_ParameterBounds
ParametersType m_ParametersBestValue
ParametersType m_ParametersConvergenceTolerance
std::vector< ParticleDatam_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

Additional Inherited Members

- Static Public Member Functions inherited from itk::SingleValuedNonLinearOptimizer
static Pointer New ()
- Protected Types inherited from itk::LightObject
typedef int InternalReferenceCountType

Member Typedef Documentation

Definition at line 63 of file itkParticleSwarmOptimizerBase.h.

Definition at line 84 of file itkParticleSwarmOptimizerBase.h.

Definition at line 83 of file itkParticleSwarmOptimizerBase.h.

Definition at line 81 of file itkParticleSwarmOptimizerBase.h.

Definition at line 82 of file itkParticleSwarmOptimizerBase.h.

Definition at line 69 of file itkParticleSwarmOptimizerBase.h.

Definition at line 62 of file itkParticleSwarmOptimizerBase.h.

Definition at line 87 of file itkParticleSwarmOptimizerBase.h.

Standard "Self" typedef.

Definition at line 60 of file itkParticleSwarmOptimizerBase.h.

Definition at line 61 of file itkParticleSwarmOptimizerBase.h.

Definition at line 80 of file itkParticleSwarmOptimizerBase.h.

Definition at line 85 of file itkParticleSwarmOptimizerBase.h.

Constructor & Destructor Documentation

itk::ParticleSwarmOptimizerBase::ParticleSwarmOptimizerBase ( )
virtual itk::ParticleSwarmOptimizerBase::~ParticleSwarmOptimizerBase ( )
itk::ParticleSwarmOptimizerBase::ParticleSwarmOptimizerBase ( const Self )

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 ( )
virtual MeasureType itk::ParticleSwarmOptimizerBase::GetFunctionConvergenceTolerance ( )
virtual bool itk::ParticleSwarmOptimizerBase::GetInitializeNormalDistribution ( )
virtual NumberOfIterationsType itk::ParticleSwarmOptimizerBase::GetMaximalNumberOfIterations ( )
virtual const char* itk::ParticleSwarmOptimizerBase::GetNameOfClass ( ) const

Run-time type information (and related methods).

Reimplemented from itk::SingleValuedNonLinearOptimizer.

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

virtual NumberOfGenerationsType itk::ParticleSwarmOptimizerBase::GetNumberOfGenerationsWithMinimalImprovement ( )
virtual NumberOfParticlesType itk::ParticleSwarmOptimizerBase::GetNumberOfParticles ( )
ParameterBoundsType itk::ParticleSwarmOptimizerBase::GetParameterBounds ( ) const
virtual ParametersType itk::ParticleSwarmOptimizerBase::GetParametersConvergenceTolerance ( )
virtual double itk::ParticleSwarmOptimizerBase::GetPercentageParticlesConverged ( )
virtual bool itk::ParticleSwarmOptimizerBase::GetPrintSwarm ( )
virtual RandomVariateGeneratorType::IntegerType itk::ParticleSwarmOptimizerBase::GetSeed ( )
virtual const std::string itk::ParticleSwarmOptimizerBase::GetStopConditionDescription ( ) const

Get the reason for termination

Reimplemented from itk::Optimizer.

virtual bool itk::ParticleSwarmOptimizerBase::GetUseSeed ( )
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 ( )

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

virtual void itk::ParticleSwarmOptimizerBase::InitializeNormalDistributionOff ( )
virtual void itk::ParticleSwarmOptimizerBase::InitializeNormalDistributionOn ( )
void itk::ParticleSwarmOptimizerBase::operator= ( const Self )
void itk::ParticleSwarmOptimizerBase::PrintParamtersType ( const ParametersType x,
std::ostream &  os 
) const
void itk::ParticleSwarmOptimizerBase::PrintSelf ( std::ostream &  os,
Indent  indent 
) const

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

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)

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)

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

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

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)

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

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)

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)

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 ( void  )

Start optimization.

Reimplemented from itk::Optimizer.

virtual void itk::ParticleSwarmOptimizerBase::UpdateSwarm ( )
protectedpure virtual

Implement your update rule in this function.

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

virtual void itk::ParticleSwarmOptimizerBase::UseSeedOff ( )
virtual void itk::ParticleSwarmOptimizerBase::UseSeedOn ( )
virtual void itk::ParticleSwarmOptimizerBase::ValidateSettings ( )

Member Data Documentation

CostFunctionType::MeasureType itk::ParticleSwarmOptimizerBase::m_FunctionBestValue

Definition at line 235 of file itkParticleSwarmOptimizerBase.h.

std::vector<MeasureType> itk::ParticleSwarmOptimizerBase::m_FunctionBestValueMemory

Definition at line 236 of file itkParticleSwarmOptimizerBase.h.

CostFunctionType::MeasureType itk::ParticleSwarmOptimizerBase::m_FunctionConvergenceTolerance

Definition at line 233 of file itkParticleSwarmOptimizerBase.h.

bool itk::ParticleSwarmOptimizerBase::m_InitializeNormalDistribution

Definition at line 226 of file itkParticleSwarmOptimizerBase.h.

NumberOfIterationsType itk::ParticleSwarmOptimizerBase::m_IterationIndex

Definition at line 238 of file itkParticleSwarmOptimizerBase.h.

NumberOfIterationsType itk::ParticleSwarmOptimizerBase::m_MaximalNumberOfIterations

Definition at line 228 of file itkParticleSwarmOptimizerBase.h.

NumberOfGenerationsType itk::ParticleSwarmOptimizerBase::m_NumberOfGenerationsWithMinimalImprovement

Definition at line 229 of file itkParticleSwarmOptimizerBase.h.

NumberOfParticlesType itk::ParticleSwarmOptimizerBase::m_NumberOfParticles

Definition at line 227 of file itkParticleSwarmOptimizerBase.h.

ParameterBoundsType itk::ParticleSwarmOptimizerBase::m_ParameterBounds

Definition at line 230 of file itkParticleSwarmOptimizerBase.h.

ParametersType itk::ParticleSwarmOptimizerBase::m_ParametersBestValue

Definition at line 237 of file itkParticleSwarmOptimizerBase.h.

ParametersType itk::ParticleSwarmOptimizerBase::m_ParametersConvergenceTolerance

Definition at line 231 of file itkParticleSwarmOptimizerBase.h.

std::vector<ParticleData> itk::ParticleSwarmOptimizerBase::m_Particles

Definition at line 234 of file itkParticleSwarmOptimizerBase.h.

double itk::ParticleSwarmOptimizerBase::m_PercentageParticlesConverged

Definition at line 232 of file itkParticleSwarmOptimizerBase.h.

bool itk::ParticleSwarmOptimizerBase::m_PrintSwarm

Definition at line 224 of file itkParticleSwarmOptimizerBase.h.

RandomVariateGeneratorType::IntegerType itk::ParticleSwarmOptimizerBase::m_Seed

Definition at line 239 of file itkParticleSwarmOptimizerBase.h.

std::ostringstream itk::ParticleSwarmOptimizerBase::m_StopConditionDescription

Definition at line 225 of file itkParticleSwarmOptimizerBase.h.

bool itk::ParticleSwarmOptimizerBase::m_UseSeed

Definition at line 240 of file itkParticleSwarmOptimizerBase.h.

The documentation for this class was generated from the following file: