gov.sandia.cognition.learning.function.scalar

Class IdentityScalarFunction

java.lang.Object

gov.sandia.cognition.util.AbstractCloneableSerializable

gov.sandia.cognition.math.AbstractScalarFunction<java.lang.Double>

gov.sandia.cognition.math.AbstractUnivariateScalarFunction

gov.sandia.cognition.math.AbstractDifferentiableUnivariateScalarFunction

gov.sandia.cognition.learning.function.scalar.IdentityScalarFunction

All Implemented Interfaces:

Evaluator<java.lang.Double,java.lang.Double>, DifferentiableEvaluator<java.lang.Double,java.lang.Double,java.lang.Double>, DifferentiableUnivariateScalarFunction, ScalarFunction<java.lang.Double>, UnivariateScalarFunction, CloneableSerializable, java.io.Serializable, java.lang.Cloneable

public class IdentityScalarFunction
extends AbstractDifferentiableUnivariateScalarFunction

A univariate scalar identity function: f(x) = x. This function simply acts as a pass-through, where evaluate(input) == input for any input. The derivative is always equal to 1.0. This is for those classes that expect an evaluator, but you don't want to alter the value of the function, like a FeedforwardNeuralNetwork. Note: prior to 3.3.0, this class was named "LinearFunction". Using LinearFunction with default values will produce the same result. However, it how has additional parameters.

Since:

3.3.3

Author:

Kevin R. Dixon

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
IdentityScalarFunction() Creates a new LinearFunction.

Method Summary

Modifier and Type	Method and Description
IdentityScalarFunction	clone() This makes public the clone method on the Object class and removes the exception that it throws.
double	differentiate(double input) Differentiates the output of the function about the given input
double	evaluate(double input) Produces a double output for the given double input
java.lang.Double	evaluate(java.lang.Double input) Evaluates the function on the given input and returns the output.
double	evaluateAsDouble(java.lang.Double input) Evaluates the scalar function as a double.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface gov.sandia.cognition.math.DifferentiableUnivariateScalarFunction

differentiate

Constructor Detail

IdentityScalarFunction

public IdentityScalarFunction()

Creates a new LinearFunction.

Method Detail

clone

public IdentityScalarFunction clone()

Description copied from class: AbstractCloneableSerializable

This makes public the clone method on the Object class and removes the exception that it throws. Its default behavior is to automatically create a clone of the exact type of object that the clone is called on and to copy all primitives but to keep all references, which means it is a shallow copy. Extensions of this class may want to override this method (but call super.clone() to implement a "smart copy". That is, to target the most common use case for creating a copy of the object. Because of the default behavior being a shallow copy, extending classes only need to handle fields that need to have a deeper copy (or those that need to be reset). Some of the methods in ObjectUtil may be helpful in implementing a custom clone method. Note: The contract of this method is that you must use super.clone() as the basis for your implementation.

Specified by:

clone in interface CloneableSerializable

Overrides:

clone in class AbstractCloneableSerializable

Returns:

A clone of this object.

evaluate

public java.lang.Double evaluate(java.lang.Double input)

Description copied from interface: Evaluator

Evaluates the function on the given input and returns the output.

Parameters:

input - The input to evaluate.

Returns:

The output produced by evaluating the input.

evaluate

public double evaluate(double input)

Description copied from interface: UnivariateScalarFunction

Produces a double output for the given double input

Parameters:

input - Input to the Evaluator

Returns:

output at the given input

evaluateAsDouble

public double evaluateAsDouble(java.lang.Double input)

Description copied from interface: ScalarFunction

Evaluates the scalar function as a double.

Parameters:

input - The input value.

Returns:

The scalar output calculated from the given input.

differentiate

public double differentiate(double input)

Description copied from interface: DifferentiableUnivariateScalarFunction

Differentiates the output of the function about the given input

Parameters:

input - Input about which to compute the derivative of the function output

Returns:

Derivative of the output with respect to the input