agi.foundation.numericalmethods.advanced

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

Class PartialDerivativesEvaluator

java.lang.Object

agi.foundation.Function2<JulianDate,T>

agi.foundation.MotionEvaluator1<Matrix>

agi.foundation.geometry.DynamicMatrixEvaluator

agi.foundation.numericalmethods.advanced.PartialDerivativesEvaluator

All Implemented Interfaces:

IDisposable, IEvaluator, IEvaluator1<Matrix>, ICloneWithContext, IIsTimeVarying, IThreadAware, IAvailability, AutoCloseable

public abstract class PartialDerivativesEvaluator
extends DynamicMatrixEvaluator

An interface for an evaluator that takes a JulianDate, order, and list of inputs and returns the partial derivatives of itself with respect to those inputs.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PartialDerivativesEvaluator(EvaluatorGroup group, List<IPartialDifferentiable> independentVariables, IPartialDifferentiable partialsOf, List<IPartialDifferentiable> withRespectTo) Initializes a new instance that will evaluate the partial derivatives of the given partialsOf IPartialDifferentiable with respect to the given withRespectTo list of IPartialDifferentiable.
protected	PartialDerivativesEvaluator(PartialDerivativesEvaluator existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.

Method Summary

Modifier and Type	Method and Description
Matrix	evaluate(JulianDate date) Calls PartialDerivativesEvaluator.evaluatePartialsOfChildren(agi.foundation.time.JulianDate) to calculate the partials derivatives of DependentVariable (get) with respect to all variables in IndependentVariables (get) except for DependentVariable (get), and then adds on the terms for the partial derivatives of DependentVariable (get) with respect to itself, if necessary.
Motion1<Matrix>	evaluate(JulianDate date, int order) PartialDerivativeEvaluators only calculate zeroth order values, this method returns a Motion1 of order zero regardless of the requested order.
abstract Matrix	evaluatePartialsOfChildren(JulianDate date) Evaluates the partials derivatives of DependentVariable (get) with respect to all variables in IndependentVariables (get) except for DependentVariable (get), as that is taken care of by PartialDerivativesEvaluator.evaluate(JulianDate).
IEvaluator	getCachingWrapper() Gets a version of this evaluator that caches the previously computed value so that if it is evaluated twice at the same date the computation is done only once.
IPartialDifferentiable	getDependentVariable() Gets the IPartialDifferentiable identifying the object that the partial derivatives calculated during evaluation are of.
List<IPartialDifferentiable>	getIndependentVariables() Gets the list of IPartialDifferentiables identifying the objects that the partial derivatives calculated during evaluation are with respect to.

Methods inherited from class agi.foundation.geometry.DynamicMatrixEvaluator

getColumnDimension, getRowDimension

Methods inherited from class agi.foundation.MotionEvaluator1

evaluate, evaluate, evaluate, evaluate, getAvailabilityIntervals, getAvailabilityIntervals, getGroup, getIsTimeVarying, isAvailable, updateEvaluatorReferences

Methods inherited from class agi.foundation.Function2

clone, dispose, dispose, getIsThreadSafe, getNextSampleSuggestion

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.IThreadAware

getIsThreadSafe

Methods inherited from interface agi.foundation.infrastructure.ICloneWithContext

clone

Methods inherited from interface agi.foundation.compatibility.IDisposable

close, dispose

Constructor Detail

PartialDerivativesEvaluator

protected PartialDerivativesEvaluator(@Nonnull
                                      EvaluatorGroup group,
                                      @Nonnull
                                      List<IPartialDifferentiable> independentVariables,
                                      @Nonnull
                                      IPartialDifferentiable partialsOf,
                                      @Nonnull
                                      List<IPartialDifferentiable> withRespectTo)

Initializes a new instance that will evaluate the partial derivatives of the given partialsOf IPartialDifferentiable with respect to the given withRespectTo list of IPartialDifferentiable.

The RowDimension (get) of this instance will be equal to the Dimension (get) of partialsOf. The ColumnDimension (get) of this instance will be equal to the summation of the Dimension (get) of objects in the withRespectTo list.

Parameters:

group - The group that contains this evaluator.

independentVariables - The list of IPartialDifferentiable representing the independent variables of the partial derivative calculation.

partialsOf - The IPartialDifferentiable that the evaluated matrix will represent partials of.

withRespectTo - The list of IPartialDifferentiables from the independentVariables that partialsOf has non-zero partials with respect to. This could be an empty list, a subset of the independentVariables list, or the entire independentVariable list. Do not include partialsOf in this list. If partialsOf is an independentVariable this base class constructor will perform the necessary adjustments to account for the partial derivatives of the subject with respect to itself.

PartialDerivativesEvaluator

protected PartialDerivativesEvaluator(@Nonnull
                                      PartialDerivativesEvaluator 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

getCachingWrapper

public IEvaluator getCachingWrapper()

Gets a version of this evaluator that caches the previously computed value so that if it is evaluated twice at the same date the computation is done only once.

This method is called by EvaluatorGroup to create a caching version of an evaluator that is shared between multiple computations.

To implement this method in your own evaluator, construct and return a caching version of the evaluator's base class. For example, if your evaluator implements IEvaluator1 directly, return an instance of CachingEvaluator. In many cases, such as when implementing a PointEvaluator this method does not need to be overridden because the default implementation returns an appropriate caching wrapper already. If you do not want the last value computed by your evaluator to ever be cached, or if your evaluator does its own caching internally, this method can return this.

Shows an example implementation in an evaluator that implements IEvaluator1 directly, where T is double.

@Override
public IEvaluator getCachingWrapper() {
    return new CachingEvaluator<Double>(this);
}

Specified by:

getCachingWrapper in interface IEvaluator

Overrides:

getCachingWrapper in class DynamicMatrixEvaluator

Returns:

A caching version of this evaluator. If a caching version is not available, or if this object does its own caching, this should be returned by this method.

getDependentVariable

public final IPartialDifferentiable getDependentVariable()

Gets the IPartialDifferentiable identifying the object that the partial derivatives calculated during evaluation are of.

getIndependentVariables

public final List<IPartialDifferentiable> getIndependentVariables()

Gets the list of IPartialDifferentiables identifying the objects that the partial derivatives calculated during evaluation are with respect to.

As an optimization this is typically only the subset of the independentVariables provided to IPartialDifferentiable.getPartialDerivativesEvaluator(java.util.List<agi.foundation.numericalmethods.advanced.IPartialDifferentiable>, agi.foundation.EvaluatorGroup) for which the DependentVariable (get) has non-zero partials, however a user-implemented PartialDerivativesEvaluator does not have to follow that pattern.

This list of variables corresponds to the columns of the Matrix produced by PartialDerivativesEvaluator.evaluate(JulianDate). Each IPartialDifferentiable in this list has a number of columns equal to its Dimension (get), and those column groupings follow the same order as this list. In addition, this list, while possible a subset of the independent variables specified by the user, will always be in the same order as that original list.

evaluate

@Nonnull
public Motion1<Matrix> evaluate(@Nonnull
                                          JulianDate date,
                                          int order)

PartialDerivativeEvaluators only calculate zeroth order values, this method returns a Motion1 of order zero regardless of the requested order.

Specified by:

evaluate in class MotionEvaluator1<Matrix>

Parameters:

date - The date at which to calculate the partial derivatives.

order - This requested order is disregarded.

Returns:

A Motion containing the Matrix representing the partial derivatives of the DependentVariable (get) object with respect to the objects in IndependentVariables (get).

evaluate

public Matrix evaluate(@Nonnull
                       JulianDate date)

Calls PartialDerivativesEvaluator.evaluatePartialsOfChildren(agi.foundation.time.JulianDate) to calculate the partials derivatives of DependentVariable (get) with respect to all variables in IndependentVariables (get) except for DependentVariable (get), and then adds on the terms for the partial derivatives of DependentVariable (get) with respect to itself, if necessary.

Specified by:

evaluate in interface IEvaluator1<Matrix>

Overrides:

evaluate in class MotionEvaluator1<Matrix>

Parameters:

date - The date at which to calculate the partial derivatives.

Returns:

A Motion containing the Matrix representing the partial derivatives of the DependentVariable (get) object with respect to the objects in IndependentVariables (get).

evaluatePartialsOfChildren

public abstract Matrix evaluatePartialsOfChildren(@Nonnull
                                                  JulianDate date)

Evaluates the partials derivatives of DependentVariable (get) with respect to all variables in IndependentVariables (get) except for DependentVariable (get), as that is taken care of by PartialDerivativesEvaluator.evaluate(JulianDate).

Parameters:

date - The date at which to calculate the partial derivatives.

Returns:

A Motion containing the Matrix representing the partial derivatives of the DependentVariable (get) object with respect to any of the objects (with the exception of DependentVariable (get)) in IndependentVariables (get).