agi.foundation.segmentpropagation

(agi.foundation.segmentpropagation-2024r2.jar)

Class InitialStateSegment<T extends ITimeBasedState>

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.segmentpropagation.SegmentDefinition

agi.foundation.segmentpropagation.InitialStateSegment<T>

Type Parameters:

T - The type of the initial state. When making derived types of this, you generally will want to specify the specific type of state you want to use.

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

Direct Known Subclasses:

NumericalInitialStateSegment

public class InitialStateSegment<T extends ITimeBasedState>
extends SegmentDefinition

Represents an initial state for a SegmentPropagator. Generally this should be the first non-SegmentList segment to get propagated.

This segment stores an ITimeBasedState set by the user, and pass that single state out when it's propagated as its SegmentResults. It will ignore the "previous segment's" state that gets passed to the propagate method.

This segments propagator returns a SegmentResults and can not be cast to any more specific type.

Constructor Summary

Constructors

Modifier	Constructor and Description
	InitialStateSegment() Initializes a new instance.
protected	InitialStateSegment(InitialStateSegment<T> existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	InitialStateSegment(T state) Initializes a new instance.

Method Summary

Modifier and Type	Method and Description
void	addPropagationFinishedEvent(EventHandler<SegmentPropagationEventArgs> value) An event that gets raised when propagation is complete.
protected boolean	checkForSameDefinition(InitialStateSegment<T> other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(SegmentDefinition other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
Object	clone(CopyContext context) Clones this object using the specified context.
protected int	computeCurrentDefinitionHashCode() Computes a hash code based on the current properties of this object.
protected SegmentPropagator	createSegmentPropagator(EvaluatorGroup group, SegmentDefinition previousSegment) Creates, configures, and returns the SegmentPropagator for this segment.
DelegateBasedVariable<InitialStateSegmentConfiguration>	createVariable(double maximumStep, double perturbation, SetVariableCallback<T> setter) Creates a DelegateBasedVariable based on this segments configuration, which is the state that will be returned when this segment is propagated.
DelegateBasedVariable<InitialStateSegmentConfiguration>	createVariable(double maximumStep, double perturbation, SetVariableCallback<T> setter, SolverVariableScaling scaling) Creates a DelegateBasedVariable based on this segments configuration, which is the state that will be returned when this segment is propagated.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
T	getInitialState() Gets the initial state.
void	removePropagationFinishedEvent(EventHandler<SegmentPropagationEventArgs> value) An event that gets raised when propagation is complete.
void	setInitialState(T value) Sets the initial state.

Methods inherited from class agi.foundation.segmentpropagation.SegmentDefinition

checkForSameDefinition, containsElement, getDefinedIn, getElementAdapter, getElements, getName, getNextStateBehavior, getPassAllElementsToNextSegment, getPropagationDirection, getSegmentPropagator, getSegmentPropagator, getSegmentPropagator, getSegmentPropagator, removeElement, setElementAndAdapter, setName, setNextStateBehavior, setPropagationDirection, toString

Methods inherited from class agi.foundation.infrastructure.DefinitionalObject

areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, dictionaryItemsAreSameDefinition, freeze, freezeAggregatedObjects, getCollectionHashCode, getCollectionHashCode, getCollectionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDictionaryHashCode, getIsFrozen, isSameDefinition, throwIfFrozen

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

InitialStateSegment

public InitialStateSegment()

Initializes a new instance.

InitialStateSegment

public InitialStateSegment(T state)

Initializes a new instance.

Parameters:

state - The initial state that this segment will propagate.

InitialStateSegment

protected InitialStateSegment(@Nonnull
                              InitialStateSegment<T> existingInstance,
                              @Nonnull
                              CopyContext context)

Initializes a new instance as a copy of an existing instance.

See ICloneWithContext.clone(CopyContext) for more information about how to implement this constructor in a derived class.

Parameters:

existingInstance - The existing instance to copy.

context - A CopyContext that controls the depth of the copy.

Throws:

ArgumentNullException - Thrown when existingInstance or context is null.

Method Detail

clone

public Object clone(CopyContext context)

Clones this object using the specified context.

This method should be implemented to call a copy constructor on the class of the object being cloned. The copy constructor should take the CopyContext as a parameter in addition to the existing instance to copy. The copy constructor should first call CopyContext.addObjectMapping(T, T) to identify the newly constructed instance as a copy of the existing instance. It should then copy all fields, using CopyContext.updateReference(T) to copy any reference fields.

A typical implementation of ICloneWithContext:

public static class MyClass implements ICloneWithContext {
    public MyClass(MyClass existingInstance, CopyContext context) {
        context.addObjectMapping(existingInstance, this);
        someReference = context.updateReference(existingInstance.someReference);
    }

    @Override
    public final Object clone(CopyContext context) {
        return new MyClass(this, context);
    }

    private Object someReference;
}

In general, all fields that are reference types should be copied with a call to CopyContext.updateReference(T). There are a couple of exceptions:

1. Fields that are aggregate parts of the object should always be copied. A referenced object is an aggregate if properties or methods on the object being copied can modify the externally-visible value of the referenced object.
2. If the semantics of the referenced object require that it have a single parent, owner, context, etc., and the object being copied is that parent, owner, or context, then the referenced object should always be copied.

If one of these exceptions applies, the CopyContext should be given an opportunity to update the reference before the reference is copied explicitly. Use CopyContext.updateReference(T) to update the reference. If CopyContext.updateReference(T) returns the original object, indicating that the context does not have a replacement registered, then copy the object manually by invoking a Clone method, a copy constructor, or by manually constructing a new instance and copying the values.

alwaysCopy = context.updateReference(existingInstance.alwaysCopy);
if (existingInstance.alwaysCopy != null && alwaysCopy == existingInstance.alwaysCopy) {
    alwaysCopy = (AlwaysCopy) existingInstance.alwaysCopy.clone(context);
}

If you are implementing an evaluator (a class that implements IEvaluator), the IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) method shares some responsibilities with the copy context constructor. Code duplication can be avoided by doing the following:

1. For references to other evaluators ONLY, simply assign the reference in the constructor instead of calling CopyContext.updateReference(T). You should still call CopyContext.updateReference(T) on any references to non-evaluators.
2. Call IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as the last line in the constructor and pass it the same CopyContext passed to the constructor.
3. Implement IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as normal. See the reference documentation for IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) for more information on implementing that method.

public MyClass(MyClass existingInstance, CopyContext context) {
    super(existingInstance, context);
    someReference = context.updateReference(existingInstance.someReference);
    evaluatorReference = existingInstance.evaluatorReference;
    updateEvaluatorReferences(context);
}

@Override
public void updateEvaluatorReferences(CopyContext context) {
    evaluatorReference = context.updateReference(evaluatorReference);
}

@Override
public Object clone(CopyContext context) {
    return new MyClass(this, context);
}

private Object someReference;
private IEvaluator evaluatorReference;

Specified by:

clone in interface ICloneWithContext

Specified by:

clone in class DefinitionalObject

Parameters:

context - The context to use to perform the copy.

Returns:

A new instance which is a copy of this object.

checkForSameDefinition

protected final boolean checkForSameDefinition(SegmentDefinition other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Specified by:

checkForSameDefinition in class SegmentDefinition

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

checkForSameDefinition

protected boolean checkForSameDefinition(@Nullable
                                         InitialStateSegment<T> other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

computeCurrentDefinitionHashCode

protected int computeCurrentDefinitionHashCode()

Computes a hash code based on the current properties of this object. Derived classes MUST override this method and compute a hash code that combines: a unique hash code seed, the base implementation result, and the hash codes of all new fields introduced by the derived class which are used in the InitialStateSegment.checkForSameDefinition(agi.foundation.segmentpropagation.SegmentDefinition) method.

Overrides:

computeCurrentDefinitionHashCode in class SegmentDefinition

Returns:

The computed hash code.

enumerateDependencies

public void enumerateDependencies(DependencyEnumerator enumerator)

Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon. Derived classes which contain additional dependencies MUST override this method, call the base implementation, and enumerate dependencies introduced by the derived class.

Specified by:

enumerateDependencies in interface IEnumerateDependencies

Overrides:

enumerateDependencies in class DefinitionalObject

Parameters:

enumerator - The enumerator that is informed of the dependencies of this object.

createVariable

@Nonnull
public final DelegateBasedVariable<InitialStateSegmentConfiguration> createVariable(double maximumStep,
                                                                                              double perturbation,
                                                                                              SetVariableCallback<T> setter,
                                                                                              SolverVariableScaling scaling)

Creates a DelegateBasedVariable based on this segments configuration, which is the state that will be returned when this segment is propagated. This is a helper method to provide variables for the TargetedSegmentListDifferentialCorrector.

Parameters:

maximumStep - The maximum step that the variable should take.

perturbation - The perturbation that should be used when finding the functions derivative with respect to this variable.

setter - The delegate that will set the value in the configuration. The value of the variable passed into this delegate is the delta that must be added to the relevant value in the configuration, not the total value that the value in the delegate should be.

scaling - The type of scaling to be used on the variable.

Returns:

The configured DelegateBasedVariable.

createVariable

@Nonnull
public final DelegateBasedVariable<InitialStateSegmentConfiguration> createVariable(double maximumStep,
                                                                                              double perturbation,
                                                                                              SetVariableCallback<T> setter)

Creates a DelegateBasedVariable based on this segments configuration, which is the state that will be returned when this segment is propagated. This is a helper method to provide variables for the TargetedSegmentListDifferentialCorrector.

Parameters:

maximumStep - The maximum step that the variable should take.

perturbation - The perturbation that should be used when finding the functions derivative with respect to this variable.

setter - The delegate that will set the value in the configuration. The value of the variable passed into this delegate is the delta that must be added to the relevant value in the configuration, not the total value that the value in the delegate should be.

Returns:

The configured DelegateBasedVariable.

addPropagationFinishedEvent

public void addPropagationFinishedEvent(EventHandler<SegmentPropagationEventArgs> value)

An event that gets raised when propagation is complete.

Specified by:

addPropagationFinishedEvent in class SegmentDefinition

removePropagationFinishedEvent

public void removePropagationFinishedEvent(EventHandler<SegmentPropagationEventArgs> value)

An event that gets raised when propagation is complete.

Specified by:

removePropagationFinishedEvent in class SegmentDefinition

getInitialState

public final T getInitialState()

Gets the initial state. The returned ephemeris from this segment will be this state unless an TargetedSegmentListOperator in a TargetedSegmentList that has the configuration of this SegmentDefinition. That configuration will be a cloned copy of this state. This may be null as long as an initial state is passed in at propagation time.

setInitialState

public final void setInitialState(T value)

Sets the initial state. The returned ephemeris from this segment will be this state unless an TargetedSegmentListOperator in a TargetedSegmentList that has the configuration of this SegmentDefinition. That configuration will be a cloned copy of this state. This may be null as long as an initial state is passed in at propagation time.

createSegmentPropagator

protected SegmentPropagator createSegmentPropagator(EvaluatorGroup group,
                                                    SegmentDefinition previousSegment)

Creates, configures, and returns the SegmentPropagator for this segment. This method should check that all of the required properties on the concrete instance are configured properly before constructing the SegmentPropagator to be returned.

Specified by:

createSegmentPropagator in class SegmentDefinition

Parameters:

group - The group to use during creation.

previousSegment - The previous segment. Some segments will require the previousSegment to be set, whereas other will require that the previous segment not be null, whereas others will only use information from it if provided. It is up to you writing a concrete type to enforce what makes sense for your particular segment in this method.

Returns:

The propagator for this segment.