gov.sandia.cognition.learning.function.kernel
Class RadialBasisKernel

java.lang.Object
  extended by gov.sandia.cognition.util.AbstractCloneableSerializable
      extended by gov.sandia.cognition.learning.function.kernel.RadialBasisKernel
All Implemented Interfaces:
Kernel<Vectorizable>, CloneableSerializable, Serializable, Cloneable

@CodeReview(reviewer="Kevin R. Dixon",
            date="2009-07-08",
            changesNeeded=false,
            comments="Looks fine.")
public class RadialBasisKernel
extends AbstractCloneableSerializable
implements Kernel<Vectorizable>

The RadialBasisKernel implements the standard radial basis kernel, which is:
exp( -||x - y||^2 / (2 * sigma^2) )
where sigma is the parameter that controls the bandwidth of the kernel.

Since:
2.0
Author:
Justin Basilico
See Also:
Serialized Form

Field Summary
static double DEFAULT_SIGMA
          The default value for sigma is 1.0.
 
Constructor Summary
RadialBasisKernel()
          Creates a new instance of RadialBasisKernel with a default value for sigma of 1.0.
RadialBasisKernel(double sigma)
          Creates a new instance of RadialBasisKernel with the given value for sigma.
RadialBasisKernel(RadialBasisKernel other)
          Creates a new copy of a RadialBasisKernel.
 
Method Summary
 RadialBasisKernel clone()
          This makes public the clone method on the Object class and removes the exception that it throws.
 double evaluate(Vectorizable x, Vectorizable y)
          Evaluates the following kernel between the two given vectors: exp( -||x - y||^2 / (2 * sigma^2))
 double getSigma()
          Gets the sigma value that controls the bandwidth of the kernel.
 void setSigma(double sigma)
          Sets the sigma value that controls the bandwidth of the kernel.
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

DEFAULT_SIGMA

public static final double DEFAULT_SIGMA
The default value for sigma is 1.0.

See Also:
Constant Field Values
Constructor Detail

RadialBasisKernel

public RadialBasisKernel()
Creates a new instance of RadialBasisKernel with a default value for sigma of 1.0.


RadialBasisKernel

public RadialBasisKernel(double sigma)
Creates a new instance of RadialBasisKernel with the given value for sigma. Sigma is the parameter that controls the bandwidth of the kernel.

Parameters:
sigma - The sigma parameter that controls the bandwidth of the kernel.

RadialBasisKernel

public RadialBasisKernel(RadialBasisKernel other)
Creates a new copy of a RadialBasisKernel.

Parameters:
other - The RadialBasisKernel to copy.
Method Detail

clone

public RadialBasisKernel 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 double evaluate(Vectorizable x,
                       Vectorizable y)
Evaluates the following kernel between the two given vectors: exp( -||x - y||^2 / (2 * sigma^2))

Specified by:
evaluate in interface Kernel<Vectorizable>
Parameters:
x - The first vector.
y - The second vector.
Returns:
The kernel evaluated on the two given vectors.

getSigma

public double getSigma()
Gets the sigma value that controls the bandwidth of the kernel.

Returns:
The sigma value that returns the bandwidth of the kernel.

setSigma

public void setSigma(double sigma)
Sets the sigma value that controls the bandwidth of the kernel.

Parameters:
sigma - The sigma value for the kernel. Must be positive.