agi.foundation.segmentpropagation

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

Class FiniteManeuverSegment

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.segmentpropagation.SegmentDefinition

agi.foundation.segmentpropagation.PropagateSegment

agi.foundation.segmentpropagation.NumericalPropagatorSegment

agi.foundation.segmentpropagation.FiniteManeuverSegment

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class FiniteManeuverSegment
extends NumericalPropagatorSegment

A segment that will run a NumericalPropagator until a StoppingCondition is satisfied. It is assumed that some sort of rocket thrusting is occurring, so this segment will handle the configuration pertaining to fuel level stopping conditions and the state at ignition and propagation start.

The results returned when this segment is propagated is FiniteManeuverSegmentResults.

Constructor Summary

Constructors

Modifier	Constructor and Description
	FiniteManeuverSegment() Creates a new instance.
protected	FiniteManeuverSegment(FiniteManeuverSegment existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(FiniteManeuverSegment other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(NumericalPropagatorSegment 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 ScalarStoppingCondition	createLimitedFuelStoppingCondition(Scalar fuelAmount, double fuelAmountThreshold, String stoppingConditionIdentification, boolean stopPropagation) Creates a ScalarStoppingCondition that will stop when the quantity of fuel reaches the specified value.
static ScalarStoppingCondition	createLimitedFuelStoppingCondition(Scalar fuelAmount, double fuelAmountThreshold, String stoppingConditionIdentification, boolean stopPropagation, double tolerance) Creates a ScalarStoppingCondition that will stop when the fuel amount reaches the specified value.
static ScalarStoppingCondition	createOutOfFuelStoppingCondition(Scalar fuelAmount, String stoppingConditionIdentification, boolean stopPropagation) Creates a ScalarStoppingCondition that will stop when the fuel amount becomes 0.
static ScalarStoppingCondition	createOutOfFuelStoppingCondition(Scalar fuelAmount, String stoppingConditionIdentification, boolean stopPropagation, double tolerance) Creates a ScalarStoppingCondition that will stop when the fuel amount becomes 0.
protected SegmentPropagator	createSegmentPropagator(EvaluatorGroup group, SegmentDefinition previousSegment) Creates, configures, and returns the SegmentPropagator for this segment.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
protected void	freezeAggregatedObjects() Called by DefinitionalObject.freeze() to also freeze any objects that are considered to be a part of this object.
ValueDefinition<Duration>	getBurnCenteringBias() Gets a bias to use for burn centering.
ValueDefinition<Duration>	getBurnCenteringDuration() Gets the ValueDefinition that will be used for burn centering.
ValueDefinition<ITimeBasedState>	getIgnitionState() Gets a parameter that represents the ignition state, taking into account the BurnCenteringDuration (get / set) and BurnCenteringBias (get / set).
ValueDefinition<ITimeBasedState>	getPropagationStartState() Gets a parameter that represents the state at the start of this segment's propagation.
void	setBurnCenteringBias(ValueDefinition<Duration> value) Sets a bias to use for burn centering.
void	setBurnCenteringDuration(ValueDefinition<Duration> value) Sets the ValueDefinition that will be used for burn centering.

Methods inherited from class agi.foundation.segmentpropagation.NumericalPropagatorSegment

checkForSameDefinition, getDefinedIn, getElementAdapter, getElements, getPropagatorDefinition, setElementAndAdapter, setPropagatorDefinition

Methods inherited from class agi.foundation.segmentpropagation.PropagateSegment

addPropagationFinishedEvent, addStepTaken, checkForSameDefinition, clearStoppingConditionsAutoSegment, getAllowZeroElements, getMaximumDuration, getNumberOfTimesToExecuteStoppingConditionsAutoSegment, getOutputSparsity, getStopOnMaximumDurationBehavior, getStoppablePropagator, getStoppingConditions, getStoppingConditionsAutoSegment, removePropagationFinishedEvent, removeStepTaken, setMaximumDuration, setOutputSparsity, setStopOnMaximumDurationBehavior, setStoppablePropagator, setStoppingConditionAutoSegment

Methods inherited from class agi.foundation.segmentpropagation.SegmentDefinition

checkForSameDefinition, containsElement, getName, getNextStateBehavior, getPassAllElementsToNextSegment, getPropagationDirection, getSegmentPropagator, getSegmentPropagator, getSegmentPropagator, getSegmentPropagator, removeElement, setName, setNextStateBehavior, setPropagationDirection, toString

Methods inherited from class agi.foundation.infrastructure.DefinitionalObject

areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, dictionaryItemsAreSameDefinition, freeze, 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

FiniteManeuverSegment

public FiniteManeuverSegment()

Creates a new instance. BurnCenteringBias (get / set) is set to Zero (get).

FiniteManeuverSegment

protected FiniteManeuverSegment(@Nonnull
                                FiniteManeuverSegment 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

Overrides:

clone in class NumericalPropagatorSegment

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(NumericalPropagatorSegment 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).

Overrides:

checkForSameDefinition in class NumericalPropagatorSegment

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
                                         FiniteManeuverSegment 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 FiniteManeuverSegment.checkForSameDefinition(agi.foundation.segmentpropagation.NumericalPropagatorSegment) method.

Overrides:

computeCurrentDefinitionHashCode in class NumericalPropagatorSegment

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 NumericalPropagatorSegment

Parameters:

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

freezeAggregatedObjects

protected void freezeAggregatedObjects()

Called by DefinitionalObject.freeze() to also freeze any objects that are considered to be a part of this object. Derived classes which contain additional aggregated objects MUST override this method, call the base implementation, and freeze aggregated objects introduced by the derived class. The objects that need to be frozen in this method are frequently created in this object's constructor and are not settable via properties.

Overrides:

freezeAggregatedObjects in class NumericalPropagatorSegment

createOutOfFuelStoppingCondition

@Nonnull
public static ScalarStoppingCondition createOutOfFuelStoppingCondition(Scalar fuelAmount,
                                                                                 String stoppingConditionIdentification,
                                                                                 boolean stopPropagation)

Creates a ScalarStoppingCondition that will stop when the fuel amount becomes 0. By default, the tolerance of the returned condition will be 1e-10.

Parameters:

fuelAmount - The amount of fuel, often the IntegrationValue (get) of a PropagationScalar.

stoppingConditionIdentification - A name for the StoppingCondition.

stopPropagation - Indicates if the StoppingCondition actually stops propagation, or if it should only indicate when fuel runs out but allow propagation to continue with 0 fuel remaining.

Returns:

A ScalarStoppingCondition that will stop when the fuel amount becomes 0.

createOutOfFuelStoppingCondition

@Nonnull
public static ScalarStoppingCondition createOutOfFuelStoppingCondition(Scalar fuelAmount,
                                                                                 String stoppingConditionIdentification,
                                                                                 boolean stopPropagation,
                                                                                 double tolerance)

Creates a ScalarStoppingCondition that will stop when the fuel amount becomes 0.

Parameters:

fuelAmount - The amount of fuel, often the IntegrationValue (get) of a PropagationScalar.

stoppingConditionIdentification - A name for the StoppingCondition.

stopPropagation - Indicates if the StoppingCondition actually stops propagation, or if it should only indicate when fuel runs out but allow propagation continue with 0 fuel remaining.

tolerance - The tolerance to use.

Returns:

A ScalarStoppingCondition that will stop propagation or otherwise indicate when the fuel quantity becomes 0.

createLimitedFuelStoppingCondition

@Nonnull
public static ScalarStoppingCondition createLimitedFuelStoppingCondition(Scalar fuelAmount,
                                                                                   double fuelAmountThreshold,
                                                                                   String stoppingConditionIdentification,
                                                                                   boolean stopPropagation)

Creates a ScalarStoppingCondition that will stop when the quantity of fuel reaches the specified value. By default, the tolerance of the returned condition will be 1e-10.

Parameters:

fuelAmount - The amount of fuel, often the IntegrationValue (get) of a PropagationScalar.

fuelAmountThreshold - The amount of fuel that the returned condition will stop at.

stoppingConditionIdentification - A name for the StoppingCondition.

stopPropagation - Indicates if the StoppingCondition actually stops propagation, or if it should only indicate when fuel runs out but allow propagation continue with 0 fuel remaining.

Returns:

A ScalarStoppingCondition that will stop when the fuel amount reaches the specified value.

createLimitedFuelStoppingCondition

@Nonnull
public static ScalarStoppingCondition createLimitedFuelStoppingCondition(Scalar fuelAmount,
                                                                                   double fuelAmountThreshold,
                                                                                   String stoppingConditionIdentification,
                                                                                   boolean stopPropagation,
                                                                                   double tolerance)

Creates a ScalarStoppingCondition that will stop when the fuel amount reaches the specified value.

Parameters:

fuelAmount - The amount of fuel, often the IntegrationValue (get) of a PropagationScalar.

fuelAmountThreshold - The amount of fuel that the returned condition will stop at.

stoppingConditionIdentification - A name for the StoppingCondition.

stopPropagation - Indicates if the StoppingCondition actually stops propagation, or if it should only indicate when fuel runs out but allow propagation continue with 0 fuel remaining.

tolerance - The tolerance to use.

Returns:

A ScalarStoppingCondition that will stop when the fuel amount reaches the specified value.

getBurnCenteringDuration

public final ValueDefinition<Duration> getBurnCenteringDuration()

Gets the ValueDefinition that will be used for burn centering. This Duration will be evaluated at propagation time. The Duration will be halved and this segment will start propagating at that computed time. This is often the threshold of a DurationStoppingCondition. By default, this is null and no time adjustment to propagation start is made.

setBurnCenteringDuration

public final void setBurnCenteringDuration(ValueDefinition<Duration> value)

Sets the ValueDefinition that will be used for burn centering. This Duration will be evaluated at propagation time. The Duration will be halved and this segment will start propagating at that computed time. This is often the threshold of a DurationStoppingCondition. By default, this is null and no time adjustment to propagation start is made.

getBurnCenteringBias

public final ValueDefinition<Duration> getBurnCenteringBias()

Gets a bias to use for burn centering. If this is a positive value, then the centering time of the burn will be moved forward by the specified amount. If this is null then no bias will be applied. This only applies if BurnCenteringDuration (get / set) is used.

setBurnCenteringBias

public final void setBurnCenteringBias(ValueDefinition<Duration> value)

Sets a bias to use for burn centering. If this is a positive value, then the centering time of the burn will be moved forward by the specified amount. If this is null then no bias will be applied. This only applies if BurnCenteringDuration (get / set) is used.

getPropagationStartState

@Nonnull
public final ValueDefinition<ITimeBasedState> getPropagationStartState()

Gets a parameter that represents the state at the start of this segment's propagation. This, in combination with the TimeFromStateValueDefinition and the geometry types that depend on a time parameter, can be used to model a vector or attitude fixed at the propagation start.

getIgnitionState

@Nonnull
public final ValueDefinition<ITimeBasedState> getIgnitionState()

Gets a parameter that represents the ignition state, taking into account the BurnCenteringDuration (get / set) and BurnCenteringBias (get / set). This, in combination with the TimeFromStateValueDefinition and the geometry types that depend on a time parameter, can be used to model a vector or attitude fixed at the time of ignition.

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.

Overrides:

createSegmentPropagator in class NumericalPropagatorSegment

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.