Package edu.cmu.tetrad.search.utils

Class KernelGaussian

java.lang.Object

edu.cmu.tetrad.search.utils.KernelGaussian

All Implemented Interfaces:

Kernel

public final class KernelGaussian
extends Object
implements Kernel

Soces the Gaussian kernel for a given bandwidth. Default bandwidth is set using the median distance heuristic.

Version:

$Id: $Id

Author:

Robert Tillman

Constructor Summary

Constructors

Constructor	Description
KernelGaussian(double sigma)	Creates a new Gaussian kernel with the given bandwidth
KernelGaussian(DataSet dataset, Node node)	Creates a new Gaussian kernel using the median distance between points to set the bandwidth

Method Summary

Modifier and Type	Method	Description
double	eval(double i, double j)	Evaluates the kernel at two points in the input space
double	getBandwidth()	getBandwidth.
void	setDefaultBw(DataSet dataset, Node node)	Sets bandwidth from data using default method
void	setMedianBandwidth(DataSet dataset, Node node)	Sets the bandwidth of the kernel to median distance between two points in the given vector

Methods inherited from class java.lang.Object

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

Constructor Details

KernelGaussian

public KernelGaussian(double sigma)

Creates a new Gaussian kernel with the given bandwidth

Parameters:

sigma - the bandwidth

KernelGaussian

public KernelGaussian(DataSet dataset,
 Node node)

Creates a new Gaussian kernel using the median distance between points to set the bandwidth

Parameters:

dataset - dataet containing variable used to set bandwidth

node - variable used to set bandwidth

Method Details

getBandwidth

public double getBandwidth()

getBandwidth.

Specified by:

getBandwidth in interface Kernel

Returns:

the bandwidth

eval

public double eval(double i,
 double j)

Evaluates the kernel at two points in the input space

Evaluates the kernel at two given points

Specified by:

eval in interface Kernel

Parameters:

i - a double

j - a double

Returns:

a double

setDefaultBw

public void setDefaultBw(DataSet dataset,
 Node node)

Sets bandwidth from data using default method

Default setting of bandwidth based on median distance heuristic

Specified by:

setDefaultBw in interface Kernel

Parameters:

dataset - a DataSet object

node - a Node object

setMedianBandwidth

public void setMedianBandwidth(DataSet dataset,
 Node node)

Sets the bandwidth of the kernel to median distance between two points in the given vector

Parameters:

dataset - dataet containing variable used to set bandwidth

node - variable used to set bandwidth