ITK  5.4.0
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itk::GradientDescentOptimizerv4Template< TInternalComputationValueType > Class Template Reference

#include <itkGradientDescentOptimizerv4.h>

Detailed Description

template<typename TInternalComputationValueType>
class itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >

Gradient descent optimizer.

GradientDescentOptimizer implements a simple gradient descent optimizer. At each iteration the current position is updated according to

\[ p_{n+1} = p_n + \mbox{learningRate} \, \frac{\partial f(p_n) }{\partial p_n} \]

Optionally, the best metric value and matching parameters can be stored and retried via GetValue() and GetCurrentPosition(). See SetReturnBestParametersAndValue().

Gradient scales can be manually set or automatically estimated, as documented in the base class. The learning rate defaults to 1.0, and can be set in two ways: 1) manually, via SetLearningRate(). Or, 2) automatically, either at each iteration or only at the first iteration, by assigning a ScalesEstimator via SetScalesEstimator(). When a ScalesEstimator is assigned, the optimizer is enabled by default to estimate learning rate only once, during the first iteration. This behavior can be changed via SetDoEstimateLearningRateAtEveryIteration() and SetDoEstimateLearningRateOnce(). For learning rate to be estimated at each iteration, the user must call SetDoEstimateLearningRateAtEveryIteration(true) and SetDoEstimateLearningRateOnce(false). When enabled, the optimizer computes learning rate(s) such that at each step, each voxel's change in physical space will be less than m_MaximumStepSizeInPhysicalUnits.

 m_LearningRate =
   m_MaximumStepSizeInPhysicalUnits /
   m_ScalesEstimator->EstimateStepScale(scaledGradient)

where m_MaximumStepSizeInPhysicalUnits defaults to the voxel spacing returned by m_ScalesEstimator->EstimateMaximumStepSize() (which is typically 1 voxel), and can be set by the user via SetMaximumStepSizeInPhysicalUnits(). When SetDoEstimateLearningRateOnce is enabled, the voxel change may become being greater than m_MaximumStepSizeInPhysicalUnits in later iterations.

Note
Unlike the previous version of GradientDescentOptimizer, this version does not have a "maximize/minimize" option to modify the effect of the metric derivative. The assigned metric is assumed to return a parameter derivative result that "improves" the optimization when added to the current parameters via the metric::UpdateTransformParameters method, after the optimizer applies scales and a learning rate.
Examples
Examples/RegistrationITKv4/MultiStageImageRegistration1.cxx, and Examples/RegistrationITKv4/MultiStageImageRegistration2.cxx.

Definition at line 78 of file itkGradientDescentOptimizerv4.h.

+ Inheritance diagram for itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >:
+ Collaboration diagram for itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >:

Public Types

using ConstPointer = SmartPointer< const Self >
 
using InternalComputationValueType = TInternalComputationValueType
 
using Pointer = SmartPointer< Self >
 
using Self = GradientDescentOptimizerv4Template
 
using Superclass = GradientDescentOptimizerBasev4Template< TInternalComputationValueType >
 
- Public Types inherited from itk::GradientDescentOptimizerBasev4Template< TInternalComputationValueType >
using ConstPointer = SmartPointer< const Self >
 
using ConvergenceMonitoringType = itk::Function::WindowConvergenceMonitoringFunction< TInternalComputationValueType >
 
using IndexRangeType = ThreadedIndexedContainerPartitioner::IndexRangeType
 
using InternalComputationValueType = TInternalComputationValueType
 
using MetricTypePointer = typename MetricType::Pointer
 
using Pointer = SmartPointer< Self >
 
using Self = GradientDescentOptimizerBasev4Template
 
using Superclass = ObjectToObjectOptimizerBaseTemplate< TInternalComputationValueType >
 
- Public Types inherited from itk::ObjectToObjectOptimizerBaseTemplate< TInternalComputationValueType >
using ConstPointer = SmartPointer< const Self >
 
using DerivativeType = typename MetricType::DerivativeType
 
using MeasureType = typename MetricType::MeasureType
 
using MetricType = ObjectToObjectMetricBaseTemplate< TInternalComputationValueType >
 
using MetricTypePointer = typename MetricType::Pointer
 
using NumberOfParametersType = typename MetricType::NumberOfParametersType
 
using ParametersType = OptimizerParameters< TInternalComputationValueType >
 
using Pointer = SmartPointer< Self >
 
using ScalesEstimatorType = OptimizerParameterScalesEstimatorTemplate< TInternalComputationValueType >
 
using ScalesType = OptimizerParameters< TInternalComputationValueType >
 
using Self = ObjectToObjectOptimizerBaseTemplate
 
using StopConditionDescriptionType = std::ostringstream
 
using StopConditionReturnStringType = std::string
 
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 void EstimateLearningRate ()
 
virtual const TInternalComputationValueType & GetConvergenceValue () const
 
const char * GetNameOfClass () const override
 
void ResumeOptimization () override
 
virtual void SetConvergenceWindowSize (SizeValueType _arg)
 
virtual void SetMinimumConvergenceValue (TInternalComputationValueType _arg)
 
void StartOptimization (bool doOnlyInitialization=false) override
 
void StopOptimization () override
 
virtual void SetLearningRate (TInternalComputationValueType _arg)
 
virtual const TInternalComputationValueType & GetLearningRate () const
 
virtual void SetMaximumStepSizeInPhysicalUnits (TInternalComputationValueType _arg)
 
virtual const TInternalComputationValueType & GetMaximumStepSizeInPhysicalUnits () const
 
virtual void SetDoEstimateLearningRateAtEachIteration (bool _arg)
 
virtual const bool & GetDoEstimateLearningRateAtEachIteration () const
 
virtual void DoEstimateLearningRateAtEachIterationOn ()
 
virtual void SetDoEstimateLearningRateOnce (bool _arg)
 
virtual const bool & GetDoEstimateLearningRateOnce () const
 
virtual void DoEstimateLearningRateOnceOn ()
 
virtual void SetReturnBestParametersAndValue (bool _arg)
 
virtual const bool & GetReturnBestParametersAndValue () const
 
virtual void ReturnBestParametersAndValueOn ()
 
- Public Member Functions inherited from itk::GradientDescentOptimizerBasev4Template< TInternalComputationValueType >
virtual const DerivativeTypeGetGradient () const
 
virtual const StopConditionObjectToObjectOptimizerEnumGetStopCondition () const
 
const StopConditionReturnStringType GetStopConditionDescription () const override
 
virtual void ModifyGradientByScales ()
 
virtual void ModifyGradientByLearningRate ()
 
- Public Member Functions inherited from itk::ObjectToObjectOptimizerBaseTemplate< TInternalComputationValueType >
virtual bool CanUseScales () const
 
virtual SizeValueType GetCurrentIteration () const
 
virtual const MeasureTypeGetCurrentMetricValue () const
 
virtual const ParametersTypeGetCurrentPosition () const
 
const char * GetNameOfClass () const override
 
virtual SizeValueType GetNumberOfIterations () const
 
virtual const ThreadIdTypeGetNumberOfWorkUnits () const
 
virtual const ScalesTypeGetScales () const
 
virtual const bool & GetScalesAreIdentity () const
 
bool GetScalesInitialized () const
 
virtual const MeasureTypeGetValue () const
 
virtual const ScalesTypeGetWeights () const
 
virtual const bool & GetWeightsAreIdentity () const
 
virtual void SetNumberOfIterations (SizeValueType _arg)
 
virtual void SetNumberOfWorkUnits (ThreadIdType number)
 
virtual void SetScalesEstimator (ScalesEstimatorType *_arg)
 
virtual void SetWeights (ScalesType _arg)
 
virtual void SetMetric (MetricType *_arg)
 
virtual MetricTypeGetModifiableMetric ()
 
virtual void SetScales (const ScalesType &scales)
 
virtual void SetDoEstimateScales (bool _arg)
 
virtual const bool & GetDoEstimateScales () const
 
virtual void DoEstimateScalesOn ()
 
- Public Member Functions inherited from itk::Object
unsigned long AddObserver (const EventObject &event, Command *)
 
unsigned long AddObserver (const EventObject &event, Command *) const
 
unsigned long AddObserver (const EventObject &event, std::function< void(const EventObject &)> function) const
 
LightObject::Pointer CreateAnother () const override
 
virtual void DebugOff () const
 
virtual void DebugOn () const
 
CommandGetCommand (unsigned long tag)
 
bool GetDebug () const
 
MetaDataDictionaryGetMetaDataDictionary ()
 
const MetaDataDictionaryGetMetaDataDictionary () const
 
virtual ModifiedTimeType GetMTime () const
 
virtual const TimeStampGetTimeStamp () 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 noexcept override
 
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
Pointer Clone () const
 
virtual void Delete ()
 
virtual int GetReferenceCount () const
 
void Print (std::ostream &os, Indent indent=0) const
 

Static Public Member Functions

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 val)
 
- Static Public Member Functions inherited from itk::LightObject
static void BreakOnError ()
 
static Pointer New ()
 

Protected Member Functions

virtual void AdvanceOneStep ()
 
 GradientDescentOptimizerv4Template ()
 
void ModifyGradientByLearningRateOverSubRange (const IndexRangeType &subrange) override
 
void ModifyGradientByScalesOverSubRange (const IndexRangeType &subrange) override
 
void PrintSelf (std::ostream &os, Indent indent) const override
 
 ~GradientDescentOptimizerv4Template () override=default
 
- Protected Member Functions inherited from itk::GradientDescentOptimizerBasev4Template< TInternalComputationValueType >
 GradientDescentOptimizerBasev4Template ()
 
 ~GradientDescentOptimizerBasev4Template () override=default
 
- Protected Member Functions inherited from itk::ObjectToObjectOptimizerBaseTemplate< TInternalComputationValueType >
void PrintSelf (std::ostream &os, Indent indent) const override
 
 ObjectToObjectOptimizerBaseTemplate ()
 
 ~ObjectToObjectOptimizerBaseTemplate () override
 
- Protected Member Functions inherited from itk::Object
 Object ()
 
bool PrintObservers (std::ostream &os, Indent indent) const
 
virtual void SetTimeStamp (const TimeStamp &timeStamp)
 
 ~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

ParametersType m_BestParameters {}
 
TInternalComputationValueType m_ConvergenceValue {}
 
MeasureType m_CurrentBestValue {}
 
TInternalComputationValueType m_LearningRate {}
 
TInternalComputationValueType m_MinimumConvergenceValue {}
 
DerivativeType m_PreviousGradient {}
 
bool m_ReturnBestParametersAndValue { false }
 
- Protected Attributes inherited from itk::GradientDescentOptimizerBasev4Template< TInternalComputationValueType >
ConvergenceMonitoringType::Pointer m_ConvergenceMonitoring {}
 
SizeValueType m_ConvergenceWindowSize {}
 
bool m_DoEstimateLearningRateAtEachIteration {}
 
bool m_DoEstimateLearningRateOnce {}
 
DerivativeType m_Gradient {}
 
TInternalComputationValueType m_MaximumStepSizeInPhysicalUnits {}
 
DomainThreader< ThreadedIndexedContainerPartitioner, Self >::Pointer m_ModifyGradientByLearningRateThreader {}
 
DomainThreader< ThreadedIndexedContainerPartitioner, Self >::Pointer m_ModifyGradientByScalesThreader {}
 
bool m_Stop { false }
 
StopConditionObjectToObjectOptimizerEnum m_StopCondition {}
 
StopConditionDescriptionType m_StopConditionDescription {}
 
bool m_UseConvergenceMonitoring {}
 
- Protected Attributes inherited from itk::ObjectToObjectOptimizerBaseTemplate< TInternalComputationValueType >
SizeValueType m_CurrentIteration {}
 
MeasureType m_CurrentMetricValue {}
 
bool m_DoEstimateScales {}
 
MetricTypePointer m_Metric {}
 
SizeValueType m_NumberOfIterations {}
 
ThreadIdType m_NumberOfWorkUnits {}
 
ScalesType m_Scales {}
 
bool m_ScalesAreIdentity {}
 
ScalesEstimatorType::Pointer m_ScalesEstimator {}
 
ScalesType m_Weights {}
 
bool m_WeightsAreIdentity {}
 
- Protected Attributes inherited from itk::LightObject
std::atomic< int > m_ReferenceCount {}
 

Member Typedef Documentation

◆ ConstPointer

template<typename TInternalComputationValueType>
using itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::ConstPointer = SmartPointer<const Self>

Definition at line 89 of file itkGradientDescentOptimizerv4.h.

◆ InternalComputationValueType

template<typename TInternalComputationValueType>
using itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::InternalComputationValueType = TInternalComputationValueType

It should be possible to derive the internal computation type from the class object.

Definition at line 99 of file itkGradientDescentOptimizerv4.h.

◆ Pointer

template<typename TInternalComputationValueType>
using itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::Pointer = SmartPointer<Self>

Definition at line 88 of file itkGradientDescentOptimizerv4.h.

◆ Self

template<typename TInternalComputationValueType>
using itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::Self = GradientDescentOptimizerv4Template

Standard class type aliases.

Definition at line 86 of file itkGradientDescentOptimizerv4.h.

◆ Superclass

template<typename TInternalComputationValueType>
using itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::Superclass = GradientDescentOptimizerBasev4Template<TInternalComputationValueType>

Definition at line 87 of file itkGradientDescentOptimizerv4.h.

Constructor & Destructor Documentation

◆ GradientDescentOptimizerv4Template()

template<typename TInternalComputationValueType>
itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GradientDescentOptimizerv4Template ( )
protected

Default constructor

◆ ~GradientDescentOptimizerv4Template()

template<typename TInternalComputationValueType>
itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::~GradientDescentOptimizerv4Template ( )
overrideprotecteddefault

Destructor

Member Function Documentation

◆ AdvanceOneStep()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::AdvanceOneStep ( )
protectedvirtual

◆ DoEstimateLearningRateAtEachIterationOn()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::DoEstimateLearningRateAtEachIterationOn ( )
virtual

Option to use ScalesEstimator for learning rate estimation at each iteration. The estimation overrides the learning rate set by SetLearningRate(). Default is false.

See also
SetDoEstimateLearningRateOnce()
SetScalesEstimator()

◆ DoEstimateLearningRateOnceOn()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::DoEstimateLearningRateOnceOn ( )
virtual

Option to use ScalesEstimator for learning rate estimation only once, during first iteration. The estimation overrides the learning rate set by SetLearningRate(). Default is true.

See also
SetDoEstimateLearningRateAtEachIteration()
SetScalesEstimator()

◆ EstimateLearningRate()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::EstimateLearningRate ( )
virtual

Estimate the learning rate based on the current gradient.

Reimplemented in itk::RegularStepGradientDescentOptimizerv4< TInternalComputationValueType >.

◆ GetConvergenceValue()

template<typename TInternalComputationValueType>
virtual const TInternalComputationValueType& itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GetConvergenceValue ( ) const
virtual

Get current convergence value. WindowConvergenceMonitoringFunction always returns output convergence value in 'TInternalComputationValueType' precision.

Reimplemented in itk::LBFGS2Optimizerv4Template< TInternalComputationValueType >.

◆ GetDoEstimateLearningRateAtEachIteration()

template<typename TInternalComputationValueType>
virtual const bool& itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GetDoEstimateLearningRateAtEachIteration ( ) const
virtual

Option to use ScalesEstimator for learning rate estimation at each iteration. The estimation overrides the learning rate set by SetLearningRate(). Default is false.

See also
SetDoEstimateLearningRateOnce()
SetScalesEstimator()

◆ GetDoEstimateLearningRateOnce()

template<typename TInternalComputationValueType>
virtual const bool& itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GetDoEstimateLearningRateOnce ( ) const
virtual

Option to use ScalesEstimator for learning rate estimation only once, during first iteration. The estimation overrides the learning rate set by SetLearningRate(). Default is true.

See also
SetDoEstimateLearningRateAtEachIteration()
SetScalesEstimator()

◆ GetLearningRate()

template<typename TInternalComputationValueType>
virtual const TInternalComputationValueType& itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GetLearningRate ( ) const
virtual

Set/Get the learning rate to apply. It is overridden by automatic learning rate estimation if enabled. See main documentation.

◆ GetMaximumStepSizeInPhysicalUnits()

template<typename TInternalComputationValueType>
virtual const TInternalComputationValueType& itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GetMaximumStepSizeInPhysicalUnits ( ) const
virtual

Set/Get the maximum step size, in physical space units.

 Only relevant when m_ScalesEstimator is set by user,
 and automatic learning rate estimation is enabled.
 See main documentation.

◆ GetNameOfClass()

template<typename TInternalComputationValueType>
const char* itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GetNameOfClass ( ) const
overridevirtual

◆ GetReturnBestParametersAndValue()

template<typename TInternalComputationValueType>
virtual const bool& itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::GetReturnBestParametersAndValue ( ) const
virtual

Flag. Set to have the optimizer track and return the best best metric value and corresponding best parameters that were calculated during the optimization. This captures the best solution when the optimizer oversteps or oscillates near the end of an optimization. Results are stored in m_CurrentMetricValue and in the assigned metric's parameters, retrievable via optimizer->GetCurrentPosition(). This option requires additional memory to store the best parameters, which can be large when working with high-dimensional transforms such as DisplacementFieldTransform.

◆ ModifyGradientByLearningRateOverSubRange()

template<typename TInternalComputationValueType>
void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::ModifyGradientByLearningRateOverSubRange ( const IndexRangeType subrange)
overrideprotectedvirtual

◆ ModifyGradientByScalesOverSubRange()

template<typename TInternalComputationValueType>
void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::ModifyGradientByScalesOverSubRange ( const IndexRangeType subrange)
overrideprotectedvirtual

Modify the gradient by scales and weights over a given index range.

Implements itk::GradientDescentOptimizerBasev4Template< TInternalComputationValueType >.

Reimplemented in itk::RegularStepGradientDescentOptimizerv4< TInternalComputationValueType >.

◆ New()

template<typename TInternalComputationValueType>
static Pointer itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::New ( )
static

New macro for creation of through a Smart Pointer

◆ PrintSelf()

template<typename TInternalComputationValueType>
void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::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::GradientDescentOptimizerBasev4Template< TInternalComputationValueType >.

Reimplemented in itk::LBFGS2Optimizerv4Template< TInternalComputationValueType >, itk::QuasiNewtonOptimizerv4Template< TInternalComputationValueType >, itk::RegularStepGradientDescentOptimizerv4< TInternalComputationValueType >, and itk::MultiGradientOptimizerv4Template< TInternalComputationValueType >.

◆ ResumeOptimization()

template<typename TInternalComputationValueType>
void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::ResumeOptimization ( )
overridevirtual

◆ ReturnBestParametersAndValueOn()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::ReturnBestParametersAndValueOn ( )
virtual

Flag. Set to have the optimizer track and return the best best metric value and corresponding best parameters that were calculated during the optimization. This captures the best solution when the optimizer oversteps or oscillates near the end of an optimization. Results are stored in m_CurrentMetricValue and in the assigned metric's parameters, retrievable via optimizer->GetCurrentPosition(). This option requires additional memory to store the best parameters, which can be large when working with high-dimensional transforms such as DisplacementFieldTransform.

◆ SetConvergenceWindowSize()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::SetConvergenceWindowSize ( SizeValueType  _arg)
virtual

Window size for the convergence checker. The convergence checker calculates convergence value by fitting to a window of the energy (metric value) profile.

The default m_ConvergenceWindowSize is set to 50 to pass all tests. It is suggested to use 10 for less stringent convergence checking.

Reimplemented in itk::LBFGS2Optimizerv4Template< TInternalComputationValueType >.

◆ SetDoEstimateLearningRateAtEachIteration()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::SetDoEstimateLearningRateAtEachIteration ( bool  _arg)
virtual

Option to use ScalesEstimator for learning rate estimation at each iteration. The estimation overrides the learning rate set by SetLearningRate(). Default is false.

See also
SetDoEstimateLearningRateOnce()
SetScalesEstimator()

◆ SetDoEstimateLearningRateOnce()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::SetDoEstimateLearningRateOnce ( bool  _arg)
virtual

Option to use ScalesEstimator for learning rate estimation only once, during first iteration. The estimation overrides the learning rate set by SetLearningRate(). Default is true.

See also
SetDoEstimateLearningRateAtEachIteration()
SetScalesEstimator()

◆ SetLearningRate()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::SetLearningRate ( TInternalComputationValueType  _arg)
virtual

Set/Get the learning rate to apply. It is overridden by automatic learning rate estimation if enabled. See main documentation.

◆ SetMaximumStepSizeInPhysicalUnits()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::SetMaximumStepSizeInPhysicalUnits ( TInternalComputationValueType  _arg)
virtual

Set/Get the maximum step size, in physical space units.

 Only relevant when m_ScalesEstimator is set by user,
 and automatic learning rate estimation is enabled.
 See main documentation.

◆ SetMinimumConvergenceValue()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::SetMinimumConvergenceValue ( TInternalComputationValueType  _arg)
virtual

Minimum convergence value for convergence checking. The convergence checker calculates convergence value by fitting to a window of the energy profile. When the convergence value reaches a small value, it would be treated as converged.

The default m_MinimumConvergenceValue is set to 1e-8 to pass all tests. It is suggested to use 1e-6 for less stringent convergence checking.

◆ SetReturnBestParametersAndValue()

template<typename TInternalComputationValueType>
virtual void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::SetReturnBestParametersAndValue ( bool  _arg)
virtual

Flag. Set to have the optimizer track and return the best best metric value and corresponding best parameters that were calculated during the optimization. This captures the best solution when the optimizer oversteps or oscillates near the end of an optimization. Results are stored in m_CurrentMetricValue and in the assigned metric's parameters, retrievable via optimizer->GetCurrentPosition(). This option requires additional memory to store the best parameters, which can be large when working with high-dimensional transforms such as DisplacementFieldTransform.

◆ StartOptimization()

template<typename TInternalComputationValueType>
void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::StartOptimization ( bool  doOnlyInitialization = false)
overridevirtual

◆ StopOptimization()

template<typename TInternalComputationValueType>
void itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::StopOptimization ( )
overridevirtual

Member Data Documentation

◆ m_BestParameters

template<typename TInternalComputationValueType>
ParametersType itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::m_BestParameters {}
protected

Definition at line 240 of file itkGradientDescentOptimizerv4.h.

◆ m_ConvergenceValue

template<typename TInternalComputationValueType>
TInternalComputationValueType itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::m_ConvergenceValue {}
protected

Definition at line 236 of file itkGradientDescentOptimizerv4.h.

◆ m_CurrentBestValue

template<typename TInternalComputationValueType>
MeasureType itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::m_CurrentBestValue {}
protected

Store the best value and related parameters.

Definition at line 239 of file itkGradientDescentOptimizerv4.h.

◆ m_LearningRate

template<typename TInternalComputationValueType>
TInternalComputationValueType itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::m_LearningRate {}
protected

Definition at line 234 of file itkGradientDescentOptimizerv4.h.

◆ m_MinimumConvergenceValue

template<typename TInternalComputationValueType>
TInternalComputationValueType itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::m_MinimumConvergenceValue {}
protected

Definition at line 235 of file itkGradientDescentOptimizerv4.h.

◆ m_PreviousGradient

template<typename TInternalComputationValueType>
DerivativeType itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::m_PreviousGradient {}
protected

Store the previous gradient value at each iteration, so we can detect the changes in gradient direction. This is needed by the regular step gradient descent and Quasi Newton optimizers.

Definition at line 249 of file itkGradientDescentOptimizerv4.h.

◆ m_ReturnBestParametersAndValue

template<typename TInternalComputationValueType>
bool itk::GradientDescentOptimizerv4Template< TInternalComputationValueType >::m_ReturnBestParametersAndValue { false }
protected

Definition at line 242 of file itkGradientDescentOptimizerv4.h.


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