agi.foundation.numericalmethods

(agi.foundation.core-2024r3.jar)

Class SolverVariableSettings

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.numericalmethods.SolverVariableSettings

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IThreadAware

public class SolverVariableSettings
extends DefinitionalObject
implements IThreadAware

The settings for a variable used by a SolvableMultivariableFunction.

Constructor Summary

Constructors

Modifier	Constructor and Description
	SolverVariableSettings(double maximumStep) Initializes a new instance.
	SolverVariableSettings(double maximumStep, double initialValue) Initializes a new instance with the tolerance set to zero and no scaling.
	SolverVariableSettings(double maximumStep, double initialValue, double variableTolerance) Initializes a new instance with no scaling.
	SolverVariableSettings(double maximumStep, double initialValue, double variableTolerance, SolverVariableScaling scaling) Initializes a new instance.
	SolverVariableSettings(double maximumStep, double initialValue, double variableTolerance, SolverVariableScaling scaling, String name) Initializes a new instance.
protected	SolverVariableSettings(SolverVariableSettings 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(DefinitionalObject other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(SolverVariableSettings 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.
double	getInitialValue() Gets the initial value of the variable.
boolean	getIsThreadSafe() Gets a value indicating whether the methods on this instance are safe to call from multiple threads simultaneously.
double	getMaximumStep() Gets the maximum step to take.
String	getName() Gets an optional name for this variable.
SolverVariableScaling	getScaling() Gets the type of scaling applied to the variable.
double	getVariableTolerance() Gets the minimum step that the variable is allowed to take.
void	setInitialValue(double value) Sets the initial value of the variable.
void	setMaximumStep(double value) Sets the maximum step to take.
void	setName(String value) Sets an optional name for this variable.
void	setScaling(SolverVariableScaling value) Sets the type of scaling applied to the variable.
void	setVariableTolerance(double value) Sets the minimum step that the variable is allowed to take.
boolean	variableChangeWithinTolerance(double currentVariableValue, double previousVariableValue) Calculates if the absolute value of change in the variable between iterations is smaller than or equal to the VariableTolerance (get / set).

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

Constructor Detail

SolverVariableSettings

public SolverVariableSettings(double maximumStep)

Initializes a new instance. The InitialValue (get / set) and tolerance will default to zero. The scaling will default to NoScalingOnVariable.

Parameters:

maximumStep - The maximum step to take when changing the value of this variable.

SolverVariableSettings

public SolverVariableSettings(double maximumStep,
                              double initialValue)

Initializes a new instance with the tolerance set to zero and no scaling.

Parameters:

maximumStep - The maximum step to take when changing the value of this variable.

initialValue - The initial value of the variable.

SolverVariableSettings

public SolverVariableSettings(double maximumStep,
                              double initialValue,
                              double variableTolerance)

Initializes a new instance with no scaling.

Parameters:

maximumStep - The maximum step to take when changing the value of this variable.

initialValue - The initial value of the variable.

variableTolerance - How small of a step the variable can take when being solved numerically. If all variables in a SolvableMultivariableFunction are asked to step by less than this value, then the MultivariableFunctionSolver can not converge and will abort.

SolverVariableSettings

public SolverVariableSettings(double maximumStep,
                              double initialValue,
                              double variableTolerance,
                              @Nonnull
                              SolverVariableScaling scaling)

Initializes a new instance.

Parameters:

maximumStep - The maximum step to take when changing the value of this variable.

initialValue - The initial value of the variable.

variableTolerance - How small of a step the variable can take when being solved numerically. If all variables in a SolvableMultivariableFunction are asked to step by less than this value, then the MultivariableFunctionSolver can not converge and will abort.

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

SolverVariableSettings

public SolverVariableSettings(double maximumStep,
                              double initialValue,
                              double variableTolerance,
                              @Nonnull
                              SolverVariableScaling scaling,
                              String name)

Initializes a new instance.

Parameters:

maximumStep - The maximum step to take when changing the value of this variable.

initialValue - The initial value of the variable.

variableTolerance - How small of a step the variable can take when being solved numerically. If all variables in a SolvableMultivariableFunction are asked to step by less than this value, then the MultivariableFunctionSolver can not converge and will abort.

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

name - An optional name for the variable settings.

SolverVariableSettings

protected SolverVariableSettings(@Nonnull
                                 SolverVariableSettings 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(DefinitionalObject 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 DefinitionalObject

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(SolverVariableSettings 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 SolverVariableSettings.checkForSameDefinition(agi.foundation.infrastructure.DefinitionalObject) method.

Overrides:

computeCurrentDefinitionHashCode in class DefinitionalObject

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.

getIsThreadSafe

public boolean getIsThreadSafe()

Gets a value indicating whether the methods on this instance are safe to call from multiple threads simultaneously.

If this property is true, all methods and properties are guaranteed to be thread safe. Conceptually, an object that returns true for this method acts as if there is a lock protecting each method and property such that only one thread at a time can be inside any method or property in the class. In reality, such locks are generally not used and are in fact discouraged. However, the user must not experience any exceptions or inconsistent behavior that would not be experienced if such locks were used.

If this property is false, the behavior when using this class from multiple threads simultaneously is undefined and may include inconsistent results and exceptions. Clients wishing to use multiple threads should call CopyForAnotherThread.copy(T) to get a separate instance of the object for each thread.

Specified by:

getIsThreadSafe in interface IThreadAware

getInitialValue

public final double getInitialValue()

Gets the initial value of the variable. By default, this is set to zero.

setInitialValue

public final void setInitialValue(double value)

Sets the initial value of the variable. By default, this is set to zero.

getMaximumStep

public final double getMaximumStep()

Gets the maximum step to take. This is to prevent a MultivariableFunctionSolver from taking too large of a step which might cause the solver to jump over relevant changes and events.

setMaximumStep

public final void setMaximumStep(double value)

Sets the maximum step to take. This is to prevent a MultivariableFunctionSolver from taking too large of a step which might cause the solver to jump over relevant changes and events.

getVariableTolerance

public final double getVariableTolerance()

Gets the minimum step that the variable is allowed to take. If a MultivariableFunctionSolver asks the function to step by a value less than this, it means that the function results will not change by any relevant amount. If all the variables are asked to step by a value less than their VariableTolerance (get / set), then the solver must abort.

setVariableTolerance

public final void setVariableTolerance(double value)

Sets the minimum step that the variable is allowed to take. If a MultivariableFunctionSolver asks the function to step by a value less than this, it means that the function results will not change by any relevant amount. If all the variables are asked to step by a value less than their VariableTolerance (get / set), then the solver must abort.

getScaling

public final SolverVariableScaling getScaling()

Gets the type of scaling applied to the variable.

setScaling

public final void setScaling(SolverVariableScaling value)

Sets the type of scaling applied to the variable.

getName

public final String getName()

Gets an optional name for this variable.

setName

public final void setName(String value)

Sets an optional name for this variable.

variableChangeWithinTolerance

public final boolean variableChangeWithinTolerance(double currentVariableValue,
                                                   double previousVariableValue)

Calculates if the absolute value of change in the variable between iterations is smaller than or equal to the VariableTolerance (get / set).

Parameters:

currentVariableValue - The variable value at the current iteration.

previousVariableValue - The variable value at the previous iteration.

Returns:

true if the variable change is within the tolerance and false if the variable change is outside the tolerance.