weka.classifiers.functions.supportVector

Class RBFKernel

java.lang.Object

weka.classifiers.functions.supportVector.Kernel

weka.classifiers.functions.supportVector.CachedKernel

weka.classifiers.functions.supportVector.RBFKernel

All Implemented Interfaces:

java.io.Serializable, CapabilitiesHandler, OptionHandler, RevisionHandler

public class RBFKernel
extends CachedKernel

The RBF kernel : K(x, y) = exp(-gamma*(x-y)^2)

Valid options are:

  -C <num>
  The size of the cache (a prime number), 0 for full cache and
  -1 to turn it off.
  (default: 250007)
 

  -G <double>
  The value to use for the gamma parameter (default: 0.01).
 

  -output-debug-info
  Enables debugging output (if available) to be printed.
  (default: off)
 

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected double	m_gamma The gamma parameter for the RBF kernel.
protected double[]	m_kernelPrecalc The diagonal values of the dot product matrix (name needs to be consistent with J.

Fields inherited from class weka.classifiers.functions.supportVector.CachedKernel

m_cacheHits, m_cacheSize, m_cacheSlots, m_kernelEvals, m_kernelMatrix, m_keys, m_numInsts, m_storage

Fields inherited from class weka.classifiers.functions.supportVector.Kernel

m_ChecksTurnedOff, m_data, m_Debug, m_DoNotCheckCapabilities

Constructor Summary

Constructors

Constructor and Description
RBFKernel() default constructor - does nothing.
RBFKernel(Instances data, int cacheSize, double gamma) Creates a new RBFKernel instance.

Method Summary

Modifier and Type	Method and Description
void	buildKernel(Instances data) Builds the kernel.
protected double	evaluate(int id1, int id2, Instance inst1) This method is overridden in subclasses to implement specific kernels.
java.lang.String	gammaTipText() Returns the tip text for this property
Capabilities	getCapabilities() Returns the Capabilities of this kernel.
double	getGamma() Gets the gamma value.
java.lang.String	getRevision() Returns the revision string.
java.lang.String	globalInfo() Returns a string describing the kernel
void	setGamma(double value) Sets the gamma value.
java.lang.String	toString() returns a string representation for the Kernel

Methods inherited from class weka.classifiers.functions.supportVector.CachedKernel

cacheSizeTipText, clean, dotProd, eval, getCacheSize, getOptions, initVars, listOptions, numCacheHits, numEvals, setCacheSize, setOptions

Methods inherited from class weka.classifiers.functions.supportVector.Kernel

debugTipText, forName, getChecksTurnedOff, getDebug, getDoNotCheckCapabilities, makeCopies, makeCopy, setChecksTurnedOff, setDebug, setDoNotCheckCapabilities

Methods inherited from class java.lang.Object

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

Field Detail

m_gamma

protected double m_gamma

The gamma parameter for the RBF kernel.

m_kernelPrecalc

protected double[] m_kernelPrecalc

The diagonal values of the dot product matrix (name needs to be consistent with J. Lindgren's implementation).

Constructor Detail

RBFKernel

public RBFKernel()

default constructor - does nothing.

RBFKernel

public RBFKernel(Instances data,
                 int cacheSize,
                 double gamma)
          throws java.lang.Exception

Creates a new RBFKernel instance.

Parameters:

data - the training dataset used.

cacheSize - the size of the cache (a prime number)

gamma - the gamma to use

Throws:

java.lang.Exception - if something goes wrong

Method Detail

buildKernel

public void buildKernel(Instances data)
                 throws java.lang.Exception

Builds the kernel. Calls the super class method and then also initializes the cache for the diagonal of the dot product matrix.

Overrides:

buildKernel in class CachedKernel

Parameters:

data - the data to base the kernel on

Throws:

java.lang.Exception - if something goes wrong

globalInfo

public java.lang.String globalInfo()

Returns a string describing the kernel

Specified by:

globalInfo in class Kernel

Returns:

a description suitable for displaying in the explorer/experimenter gui

evaluate

protected double evaluate(int id1,
                          int id2,
                          Instance inst1)
                   throws java.lang.Exception

Description copied from class: CachedKernel

This method is overridden in subclasses to implement specific kernels.

Specified by:

evaluate in class CachedKernel

Parameters:

id1 - the index of instance 1

id2 - the index of instance 2

inst1 - the instance 1 object

Returns:

the dot product

Throws:

java.lang.Exception - if something goes wrong

getCapabilities

public Capabilities getCapabilities()

Returns the Capabilities of this kernel.

Specified by:

getCapabilities in interface CapabilitiesHandler

Overrides:

getCapabilities in class Kernel

Returns:

the capabilities of this object

See Also:

Capabilities

setGamma

@OptionMetadata(description="The value to use for the gamma parameter (default: 0.01).",
                displayName="gamma",
                commandLineParamName="G",
                commandLineParamSynopsis="-G <double>",
                displayOrder=1)
public void setGamma(double value)

Sets the gamma value.

Parameters:

value - the gamma value

getGamma

public double getGamma()

Gets the gamma value.

Returns:

the gamma value

gammaTipText

public java.lang.String gammaTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

toString

public java.lang.String toString()

returns a string representation for the Kernel

Overrides:

toString in class java.lang.Object

Returns:

a string representaiton of the kernel

getRevision

public java.lang.String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class Kernel

Returns:

the revision