jsat.distributions.empirical.kernelfunc

Interface KernelFunction

All Superinterfaces:

java.io.Serializable

All Known Implementing Classes:

BiweightKF, EpanechnikovKF, GaussKF, TriweightKF, UniformKF

public interface KernelFunction
extends java.io.Serializable

Class for representing one dimensional kernel functions. Since they require no parameters and have no need for duplication, its is advised to make them singletons. See http://en.wikipedia.org/wiki/Kernel_(statistics)

Method Summary

Modifier and Type	Method and Description
double	cutOff() As the value of |u| for the kernel function approaches infinity, the value of k(u) approaches zero.
double	intK(double u) Computes the value of the finite integral from -Infinity up to the value u, of the function given by k(double)
double	k(double u) Returns the weight to be applied to a sample for the normalized distance of two data points.
double	k2() Returns the variance of the kernel function
double	kPrime(double u) Returns the value of the derivative at a point, k'(u)
java.lang.String	toString() Returns the name of this kernel function

Method Detail

k

double k(double u)

Returns the weight to be applied to a sample for the normalized distance of two data points.

Parameters:

u - the distance of the data points

Returns:

the value in [0, 1) of the amount of weight to give to the sample based on its distance

intK

double intK(double u)

Computes the value of the finite integral from -Infinity up to the value u, of the function given by k(double)

Parameters:

u - the distance of the data points

Returns:

the value of the integration

kPrime

double kPrime(double u)

Returns the value of the derivative at a point, k'(u)

Parameters:

u - the distance of the data points

Returns:

the value of the derivative at u

k2

double k2()

Returns the variance of the kernel function

Returns:

the variance of the kernel function

cutOff

double cutOff()

As the value of |u| for the kernel function approaches infinity, the value of k(u) approaches zero. This function returns the minimal absolute value of u for which k(u) returns 0

Returns:

the first value for which k(u) = 0

toString

java.lang.String toString()

Returns the name of this kernel function

Overrides:

toString in class java.lang.Object

Returns:

the name of this kernel function