org.apache.commons.math3.analysis.function
Class Gaussian

java.lang.Object
  org.apache.commons.math3.analysis.function.Gaussian

All Implemented Interfaces:

DifferentiableUnivariateFunction, UnivariateDifferentiableFunction, UnivariateFunction

public class Gaussian
extends Object
implements UnivariateDifferentiableFunction, DifferentiableUnivariateFunction

Gaussian function.

Since:

3.0

Version:

$Id: Gaussian.java 1455194 2013-03-11 15:45:54Z luc $

Nested Class Summary

static class

Gaussian.Parametric Parametric function where the input array contains the parameters of the Gaussian, ordered as follows: Norm Mean Standard deviation

Field Summary

private double	i2s2 Inverse of twice the square of the standard deviation.
private double	is Inverse of the standard deviation.
private double	mean Mean.
private double	norm Normalization factor.

Constructor Summary

Gaussian()
Normalized gaussian with zero mean and unit standard deviation.

Gaussian(double mean, double sigma)
Normalized gaussian with given mean and standard deviation.

Gaussian(double norm, double mean, double sigma)
Gaussian with given normalization factor, mean and standard deviation.

Method Summary

UnivariateFunction	derivative() Deprecated. as of 3.1, replaced by value(DerivativeStructure)
DerivativeStructure	value(DerivativeStructure t) Simple mathematical function.
double	value(double x) Compute the value of the function.
private static double	value(double xMinusMean, double norm, double i2s2)

Methods inherited from class java.lang.Object

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

Field Detail

mean

private final double mean

Mean.

is

private final double is

Inverse of the standard deviation.

i2s2

private final double i2s2

Inverse of twice the square of the standard deviation.

norm

private final double norm

Normalization factor.

Constructor Detail

Gaussian

public Gaussian(double norm,
                double mean,
                double sigma)
         throws NotStrictlyPositiveException

Gaussian with given normalization factor, mean and standard deviation.

Parameters:

norm - Normalization factor.

mean - Mean.

sigma - Standard deviation.

Throws:

NotStrictlyPositiveException - if sigma <= 0.

Gaussian

public Gaussian(double mean,
                double sigma)
         throws NotStrictlyPositiveException

Normalized gaussian with given mean and standard deviation.

Parameters:

mean - Mean.

sigma - Standard deviation.

Throws:

NotStrictlyPositiveException - if sigma <= 0.

Gaussian

public Gaussian()

Normalized gaussian with zero mean and unit standard deviation.

Method Detail

value

public double value(double x)

Compute the value of the function.

Specified by:

value in interface UnivariateFunction

Parameters:

x - Point at which the function value should be computed.

Returns:

the value of the function.

derivative

@Deprecated
public UnivariateFunction derivative()

Deprecated. as of 3.1, replaced by value(DerivativeStructure)

Returns the derivative of the function

Specified by:

derivative in interface DifferentiableUnivariateFunction

Returns:

the derivative function

value

private static double value(double xMinusMean,
                            double norm,
                            double i2s2)

Parameters:

xMinusMean - x - mean.

norm - Normalization factor.

i2s2 - Inverse of twice the square of the standard deviation.

Returns:

the value of the Gaussian at x.

value

public DerivativeStructure value(DerivativeStructure t)
                          throws DimensionMismatchException

Simple mathematical function.

UnivariateDifferentiableFunction classes compute both the value and the first derivative of the function.

Specified by:

value in interface UnivariateDifferentiableFunction

Parameters:

t - function input value

Returns:

function result

Throws:

DimensionMismatchException - if t is inconsistent with the function's free parameters or order

Since:

3.1