agi.foundation.geometry

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

Class VectorPropagationParameter

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.geometry.Vector

agi.foundation.geometry.VectorPropagationParameter

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IServiceProvider, IPartialDifferentiable

public final class VectorPropagationParameter
extends Vector
implements IPartialDifferentiable

Represents a Vector which in turn represents the value and derivatives of a coordinate vector in an integration state. This is used to define various geometries that depend on the state during integration.

Constructor Summary

Constructors

Constructor and Description
VectorPropagationParameter() Initializes a new instance.
VectorPropagationParameter(Axes axes) Initializes a new instance with the given axes of integration.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(Vector 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.
static void	configureIndicesOnEvaluator(EvaluatorGroup group, VectorPropagationParameter vector, Motion1<int[]> stateInputIndices) This is called by PropagationStateElement instances using VectorPropagationParameter so that the element can update the indices used to identify the individual values corresponding to this vector in the state during evaluation.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
int	getDimension() Gets the dimension of the values produced by the object.
VectorEvaluator	getEvaluator(EvaluatorGroup group) Gets an evaluator that can be used to find the Motion<Cartesian> of this vector at a given date with respect to the axes in which it is defined.
Axes	getIntegrationAxes() Gets the Axes used to define the state during integration.
PartialDerivativesEvaluator	getPartialDerivativesEvaluator(List<IPartialDifferentiable> independentVariables, EvaluatorGroup group) This type does not have derivatives or partial derivatives with respect to any object with the exception of itself.
PropagationStateParameter	getStateParameter() Gets a parameter which represents the state during propagation.
void	setIntegrationAxes(Axes value) Sets the Axes used to define the state during integration.
void	setStateParameter(PropagationStateParameter value) Sets a parameter which represents the state during propagation.

Methods inherited from class agi.foundation.geometry.Vector

add, add, checkForSameDefinition, createVectorDerivative, cross, divide, divide, divide, divide, dot, getEvaluator, getScalarElement, getScalarElement, getService, multiply, multiply, multiply, multiply, multiply, multiply, subtract, subtract

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, toString, wait, wait, wait

Methods inherited from interface agi.foundation.infrastructure.IEquatableDefinition

getDefinitionHashCode, isSameDefinition

Constructor Detail

VectorPropagationParameter

public VectorPropagationParameter()

Initializes a new instance.

VectorPropagationParameter

public VectorPropagationParameter(Axes axes)

Initializes a new instance with the given axes of integration.

Parameters:

axes - The axes used to define the state during integration.

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 boolean checkForSameDefinition(Vector 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 Vector

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 VectorPropagationParameter.checkForSameDefinition(agi.foundation.geometry.Vector) method.

Overrides:

computeCurrentDefinitionHashCode in class Vector

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.

getIntegrationAxes

public final Axes getIntegrationAxes()

Gets the Axes used to define the state during integration.

setIntegrationAxes

public final void setIntegrationAxes(Axes value)

Sets the Axes used to define the state during integration.

getStateParameter

public final PropagationStateParameter getStateParameter()

Gets a parameter which represents the state during propagation. In general, users should never need to explicitly set this property. It should only be set in cases where elements of a state require additional instances of a NumericalPropagator inside their implementation in order to produce their values. In such cases, it may be necessary to distinguish between the state of the exterior propagator and the state of the interior propagator. In these cases, it is up to the user to ensure that both the state and all of its elements are configured with the same parameter. Otherwise, the state will throw an exception when creating its propagator.

setStateParameter

public final void setStateParameter(PropagationStateParameter value)

Sets a parameter which represents the state during propagation. In general, users should never need to explicitly set this property. It should only be set in cases where elements of a state require additional instances of a NumericalPropagator inside their implementation in order to produce their values. In such cases, it may be necessary to distinguish between the state of the exterior propagator and the state of the interior propagator. In these cases, it is up to the user to ensure that both the state and all of its elements are configured with the same parameter. Otherwise, the state will throw an exception when creating its propagator.

getDimension

public final int getDimension()

Gets the dimension of the values produced by the object. For example, Vectors would have a dimension of three, and Scalars of one. A PartialDerivativesEvaluator created by this type will have a RowDimension (get) equal to this property, and a ColumnDimension (get) equal to the summation of the dimensions of the independent variables that this object is dependent on.

Specified by:

getDimension in interface IPartialDifferentiable

getEvaluator

public VectorEvaluator getEvaluator(EvaluatorGroup group)

Gets an evaluator that can be used to find the Motion<Cartesian> of this vector at a given date with respect to the axes in which it is defined. See VectorPropagationParameter.getEvaluator(EvaluatorGroup) for details.

This type will usually not be used directly, it is instead used by PropagationVector behind the scenes. If this type is used, such as during the implementation of a type similar to or deriving from PropagationVector, always call VectorPropagationParameter.configureIndicesOnEvaluator(agi.foundation.EvaluatorGroup, agi.foundation.geometry.VectorPropagationParameter, agi.foundation.Motion1<int[]>) prior to this method.

Specified by:

getEvaluator in class Vector

Parameters:

group - The group with which to associate the new evaluator. By grouping evaluators that are often evaluated at the same Julian dates, common computations can be performed only once for the entire group instead of multiple times for each evaluator.

Returns:

An evaluator for this vector.

configureIndicesOnEvaluator

public static void configureIndicesOnEvaluator(@Nonnull
                                               EvaluatorGroup group,
                                               @Nonnull
                                               VectorPropagationParameter vector,
                                               @Nonnull
                                               Motion1<int[]> stateInputIndices)

This is called by PropagationStateElement instances using VectorPropagationParameter so that the element can update the indices used to identify the individual values corresponding to this vector in the state during evaluation. In general, this should only be called from within the PropagationStateElement.getConverter(agi.foundation.EvaluatorGroup, agi.foundation.Motion1<int[]>) method when configuring the indices provided by the NumericalPropagatorDefinition.

The EvaluatorGroup will create an evaluator based on the StateParameter (get / set) and the IntegrationAxes (get / set) and cache it for future calls. This method updates the instance variables for the indices so that it will reflect the vector's elements within the state during evaluation. In general, this breaks the "Evaluator Pattern" by altering data on an evaluator after construction. However, so long as it is done once and only once prior to any evaluation this is deemed as following the "Evaluator Pattern" which stipulates that an evaluator should always return the same value for a given time.

Parameters:

group - The evaluator group in which to create the VectorEvaluator corresponding to this vector.

vector - The instance of the VectorPropagationParameter whose evaluator will be configured.

stateInputIndices - The indices representing the locations of the coordinates of this vector in the state during propagation.

getPartialDerivativesEvaluator

public final PartialDerivativesEvaluator getPartialDerivativesEvaluator(List<IPartialDifferentiable> independentVariables,
                                                                        EvaluatorGroup group)

This type does not have derivatives or partial derivatives with respect to any object with the exception of itself. Because of that the created PartialDerivativesEvaluator has a ColumnDimension (get) of zero if this PointPropagationParameter is not in the generalized state, and if it is in the generalized state it returns a 3x3 identity matrix.

Specified by:

getPartialDerivativesEvaluator in interface IPartialDifferentiable

Parameters:

independentVariables - The list of IPartialDifferentiable representing the independent variables that the created partial derivative evaluator calculates partials with respect to.

group - The EvaluatorGroup that will contain the created evaluator.

Returns:

The PartialDerivativesEvaluator.