/*
* File: ZeroKernel.java
* Authors: Justin Basilico
* Company: Sandia National Laboratories
* Project: Cognitive Foundry
*
* Copyright July 19, 2007, Sandia Corporation. Under the terms of Contract
* DE-AC04-94AL85000, there is a non-exclusive license for use of this work by
* or on behalf of the U.S. Government. Export of this program may require a
* license from the United States Government. See CopyrightHistory.txt for
* complete details.
*
*/
package gov.sandia.cognition.learning.function.kernel;
import gov.sandia.cognition.annotation.CodeReview;
import gov.sandia.cognition.util.AbstractCloneableSerializable;
/**
* The <code>ZeroKernel</code> always returns zero. On its own it is not useful,
* but it is useful in combination with some other kernels when there
* is some aspect of the data that needs to be ignored.
*
* @author Justin Basilico
* @since 2.0
*/
@CodeReview(
reviewer="Kevin R. Dixon",
date="2009-07-08",
changesNeeded=false,
comments="Looks fine."
)
public final class ZeroKernel
extends AbstractCloneableSerializable
implements Kernel<Object>
{
/** A static instance of this class because it has no internal fields. */
private static final ZeroKernel INSTANCE = new ZeroKernel();
/**
* Gets the single instance of this class because it has no internal data.
*
* @return The instance of the singleton.
*/
public static ZeroKernel getInstance()
{
return INSTANCE;
}
/**
* Creates a new instance of ZeroKernel.
*/
public ZeroKernel()
{
super();
}
@Override
public ZeroKernel clone()
{
return (ZeroKernel) super.clone();
}
/**
* Returns zero regardless of the input values.
*
* @param x The first item.
* @param y The second item.
* @return Zero.
*/
public double evaluate(
final Object x,
final Object y)
{
return 0.0;
}
}