agi.foundation.numericalmethods

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

Class CombinedCostFunction

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.numericalmethods.SegmentPropagatorCostFunction

agi.foundation.numericalmethods.CombinedCostFunction

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class CombinedCostFunction
extends SegmentPropagatorCostFunction

This costFunction will take the weighted and scaled sum of all of its constituent cost functions as a new cost function.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CombinedCostFunction(CombinedCostFunction existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	CombinedCostFunction(CostFunctionGoal goal, double tolerance, CostFunctionScaling scaling, double weight, List<SegmentPropagatorCostFunction> costFunctions) Initializes a new instance.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(CombinedCostFunction 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.
SegmentPropagatorCostFunctionEvaluator	getEvaluator(EvaluatorGroup group) Creates and returns the SegmentPropagatorCostFunctionEvaluator.

Methods inherited from class agi.foundation.numericalmethods.SegmentPropagatorCostFunction

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

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

CombinedCostFunction

public CombinedCostFunction(@Nonnull
                            CostFunctionGoal goal,
                            double tolerance,
                            @Nonnull
                            CostFunctionScaling scaling,
                            double weight,
                            @Nonnull
                            List<SegmentPropagatorCostFunction> costFunctions)

Initializes a new instance.

Parameters:

goal - Whether the cost function is supposed to be minimized or maximized.

tolerance - The cost function is considered to be converged if its value changes by less than this value from one iteration to the next.

scaling - Sets the type of scaling to be used on this cost function.

weight - A value multiplied by the cost function to prioritize or de-prioritize it with respect to the constraint errors of any active constraints. This is the weight of the combined cost function and is applied after the weights of its constituents are applied.

costFunctions - A list of cost functions whose Weight (get / set), Scaling (get / set), and evaluation results will be used to form the evaluation results of this cost function. All of their other properties will be ignored. This list must contain at least one element.

Throws:

ArgumentNullException - Thrown if costFunctions is null.

ArgumentException - Thrown if costFunctions is empty.

CombinedCostFunction

protected CombinedCostFunction(@Nonnull
                               CombinedCostFunction 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
                                         CombinedCostFunction 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 CombinedCostFunction.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.

getEvaluator

public SegmentPropagatorCostFunctionEvaluator getEvaluator(EvaluatorGroup group)

Creates and returns the SegmentPropagatorCostFunctionEvaluator.

Derived classes should call SegmentPropagatorCostFunction.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.