agi.foundation.numericalmethods

(agi.foundation.segmentpropagation-2025r1.jar)

Class ScalarDifferenceOfSegmentCostFunction

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.numericalmethods.SegmentPropagatorCostFunction

agi.foundation.numericalmethods.ScalarDifferenceOfSegmentCostFunction

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class ScalarDifferenceOfSegmentCostFunction
extends SegmentPropagatorCostFunction

This costFunction will take the initial and final values from a SegmentResults and evaluate the difference of a Scalar (get / set) at those times.

Constructor Summary

Constructors

Modifier	Constructor and Description
	ScalarDifferenceOfSegmentCostFunction() Initializes a new instance.
protected	ScalarDifferenceOfSegmentCostFunction(ScalarDifferenceOfSegmentCostFunction existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	ScalarDifferenceOfSegmentCostFunction(Scalar scalar, SegmentDefinition segment, CostFunctionGoal goal, double tolerance, ScalarConstraintDifference costFunctionDifference) Initializes a new instance.
	ScalarDifferenceOfSegmentCostFunction(Scalar scalar, SegmentDefinition segment, CostFunctionGoal goal, double tolerance, ScalarConstraintDifference costFunctionDifference, CostFunctionScaling scaling) Initializes a new instance.
	ScalarDifferenceOfSegmentCostFunction(Scalar scalar, SegmentDefinition segment, CostFunctionGoal goal, double tolerance, ScalarConstraintDifference costFunctionDifference, CostFunctionScaling scaling, double weight) Initializes a new instance.
	ScalarDifferenceOfSegmentCostFunction(SegmentDefinition segment, CostFunctionGoal goal, double tolerance, ScalarConstraintDifference costFunctionDifference) Initializes a new instance.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(ScalarDifferenceOfSegmentCostFunction other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(SegmentPropagatorCostFunction 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.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
ScalarConstraintDifference	getCostFunctionDifference() Gets how the difference will be computed.
SegmentPropagatorCostFunctionEvaluator	getEvaluator(EvaluatorGroup group) Creates and returns the SegmentPropagatorCostFunctionEvaluator.
TimeBasedStateParameter	getParameter() Gets the parameter to use when evaluating the Scalar (get / set).
Scalar	getScalar() Gets the Scalar to compute a value to minimize or maximize.
SegmentDefinition	getSegment() Gets the SegmentDefinition whose initial and final ephemeris points (in the StateForNextSegment (get)) will be used to compute a value.
void	setCostFunctionDifference(ScalarConstraintDifference value) Sets how the difference will be computed.
void	setScalar(Scalar value) Sets the Scalar to compute a value to minimize or maximize.
void	setSegment(SegmentDefinition value) Sets the SegmentDefinition whose initial and final ephemeris points (in the StateForNextSegment (get)) will be used to compute a value.
protected void	validateProperties() Validates that required properties are configured correctly in order to get an evaluator for this instance.

Methods inherited from class agi.foundation.numericalmethods.SegmentPropagatorCostFunction

checkForSameDefinition, freezeAggregatedObjects, getGoal, getName, getSettings, setGoal, setName, setSettings

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, toString, wait, wait, wait

Constructor Detail

ScalarDifferenceOfSegmentCostFunction

public ScalarDifferenceOfSegmentCostFunction()

Initializes a new instance.

Before ScalarDifferenceOfSegmentCostFunction.getEvaluator(agi.foundation.EvaluatorGroup) can be called, Scalar (get / set), Segment (get / set), and Goal (get / set) must be configured, and Settings (get / set) must be configured with a valid Tolerance (get / set). Scaling (get / set) defaults to NoScalingOnCostFunction.

ScalarDifferenceOfSegmentCostFunction

public ScalarDifferenceOfSegmentCostFunction(Scalar scalar,
                                             SegmentDefinition segment,
                                             @Nonnull
                                             CostFunctionGoal goal,
                                             double tolerance,
                                             @Nonnull
                                             ScalarConstraintDifference costFunctionDifference,
                                             @Nonnull
                                             CostFunctionScaling scaling)

Initializes a new instance.

Parameters:

scalar - The Scalar to minimize or maximize.

goal - Whether the cost function should be minimized or maximized.

tolerance - How small the cost function's variation between subsequent iterations must become to consider this cost function to be converged.

segment - The SegmentDefinition whose initial and final states will be used to compute the Scalar (get / set).

costFunctionDifference - The type of the difference to evaluate (first minus last, or last minus first...).

scaling - The type of scaling to be used on this constraint.

ScalarDifferenceOfSegmentCostFunction

public ScalarDifferenceOfSegmentCostFunction(Scalar scalar,
                                             SegmentDefinition segment,
                                             @Nonnull
                                             CostFunctionGoal goal,
                                             double tolerance,
                                             @Nonnull
                                             ScalarConstraintDifference costFunctionDifference,
                                             @Nonnull
                                             CostFunctionScaling scaling,
                                             double weight)

Initializes a new instance.

Parameters:

scalar - The Scalar to minimize or maximize.

goal - Whether the cost function should be minimized or maximized.

tolerance - How small the cost function's variation between subsequent iterations must become to consider this cost function to be converged.

segment - The SegmentDefinition whose initial and final states will be used to compute the Scalar (get / set).

costFunctionDifference - The type of the difference to evaluate (first minus last, or last minus first...).

scaling - The type of scaling to be used on this constraint.

weight - The weight of this cost function compared to the constraints.

ScalarDifferenceOfSegmentCostFunction

public ScalarDifferenceOfSegmentCostFunction(SegmentDefinition segment,
                                             @Nonnull
                                             CostFunctionGoal goal,
                                             double tolerance,
                                             @Nonnull
                                             ScalarConstraintDifference costFunctionDifference)

Initializes a new instance.

Parameters:

goal - Whether the cost function should be minimized or maximized.

tolerance - How small the cost function's variation between subsequent iterations must become to consider this cost function to be converged.

segment - The SegmentDefinition whose initial and final states will be used to compute the Scalar (get / set).

costFunctionDifference - The type of the difference to evaluate (first minus last, or last minus first...).

ScalarDifferenceOfSegmentCostFunction

public ScalarDifferenceOfSegmentCostFunction(Scalar scalar,
                                             SegmentDefinition segment,
                                             @Nonnull
                                             CostFunctionGoal goal,
                                             double tolerance,
                                             @Nonnull
                                             ScalarConstraintDifference costFunctionDifference)

Initializes a new instance.

Parameters:

scalar - The Scalar to minimize or maximize.

goal - Whether the cost function should be minimized or maximized.

tolerance - How small the cost function's variation between subsequent iterations must become to consider this cost function to be converged.

segment - The SegmentDefinition whose initial and final states will be used to compute the Scalar (get / set).

costFunctionDifference - The type of the difference to evaluate (first minus last, or last minus first...).

ScalarDifferenceOfSegmentCostFunction

protected ScalarDifferenceOfSegmentCostFunction(@Nonnull
                                                ScalarDifferenceOfSegmentCostFunction 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(SegmentPropagatorCostFunction 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 SegmentPropagatorCostFunction

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
                                         ScalarDifferenceOfSegmentCostFunction 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 ScalarDifferenceOfSegmentCostFunction.checkForSameDefinition(agi.foundation.numericalmethods.SegmentPropagatorCostFunction) method.

Overrides:

computeCurrentDefinitionHashCode in class SegmentPropagatorCostFunction

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 SegmentPropagatorCostFunction

Parameters:

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

getScalar

public final Scalar getScalar()

Gets the Scalar to compute a value to minimize or maximize. This Scalar must be set to evaluate at any time during the ephemeris of the Segment (get / set). The common way to do that is to create a Scalar that is built from a ParameterizedOnStateScalar, ParameterizedOnStatePoint or ParameterizedOnStateVector with this parameter as their parameter.

setScalar

public final void setScalar(Scalar value)

Sets the Scalar to compute a value to minimize or maximize. This Scalar must be set to evaluate at any time during the ephemeris of the Segment (get / set). The common way to do that is to create a Scalar that is built from a ParameterizedOnStateScalar, ParameterizedOnStatePoint or ParameterizedOnStateVector with this parameter as their parameter.

getSegment

public final SegmentDefinition getSegment()

Gets the SegmentDefinition whose initial and final ephemeris points (in the StateForNextSegment (get)) will be used to compute a value.

setSegment

public final void setSegment(SegmentDefinition value)

Sets the SegmentDefinition whose initial and final ephemeris points (in the StateForNextSegment (get)) will be used to compute a value.

getCostFunctionDifference

@Nonnull
public final ScalarConstraintDifference getCostFunctionDifference()

Gets how the difference will be computed. The final value minus the initial value is the default.

setCostFunctionDifference

public final void setCostFunctionDifference(@Nonnull
                                            ScalarConstraintDifference value)

Sets how the difference will be computed. The final value minus the initial value is the default.

getParameter

@Nonnull
public final TimeBasedStateParameter getParameter()

Gets the parameter to use when evaluating the Scalar (get / set). The Scalar (get / set) must be set to evaluate at any time during the ephemeris of the Segment (get / set). The common way to do that is to create a Scalar that is built from a ParameterizedOnStateScalar, ParameterizedOnStatePoint or ParameterizedOnStateVector with this parameter as their parameter.

getEvaluator

public SegmentPropagatorCostFunctionEvaluator getEvaluator(EvaluatorGroup group)

Creates and returns the SegmentPropagatorCostFunctionEvaluator.

Derived classes should call ScalarDifferenceOfSegmentCostFunction.validateProperties() to check properties owned by this base class, as well as validate their own properties.

Specified by:

getEvaluator in class SegmentPropagatorCostFunction

Parameters:

group - The EvaluatorGroup to use to create any necessary evaluators for this constraint.

Returns:

The fully configured cost function evaluator.

validateProperties

protected void validateProperties()

Validates that required properties are configured correctly in order to get an evaluator for this instance. Derived classes should call this method when implementing ScalarDifferenceOfSegmentCostFunction.getEvaluator(agi.foundation.EvaluatorGroup), as well as validate their own properties.

Overrides:

validateProperties in class SegmentPropagatorCostFunction

Throws:

PropertyInvalidException - Thrown when Segment (get / set) or Scalar (get / set) is null.

PropertyInvalidException - Thrown when Settings (get / set) is null, or Scaling (get / set) is null, or Tolerance (get / set) is not greater than zero.