de.lmu.ifi.dbs.elki.math
Class ErrorFunctions

java.lang.Object
  de.lmu.ifi.dbs.elki.math.ErrorFunctions

public final class ErrorFunctions
extends Object

Some mathematical error functions. Numerical approximations. Currently, this class contains the erf and erfc error functions (Gaussian = normal distribution)

Author:

Erich Schubert

Field Summary

(package private) static double[]	a
(package private) static double[]	b
(package private) static double[]	c
(package private) static double[]	d
(package private) static double	onebysqrtpi
(package private) static double[]	p
(package private) static double[]	q

Constructor Summary

ErrorFunctions()

Method Summary

static double	erf(double x) Error function for Gaussian distributions = Normal distributions.
static double	erfc(double x) Complementary error function for Gaussian distributions = Normal distributions.

Methods inherited from class java.lang.Object

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

Field Detail

a

static final double[] a

b

static final double[] b

c

static final double[] c

d

static final double[] d

p

static final double[] p

q

static final double[] q

onebysqrtpi

static final double onebysqrtpi

Constructor Detail

ErrorFunctions

public ErrorFunctions()

Method Detail

erfc

public static final double erfc(double x)

Complementary error function for Gaussian distributions = Normal distributions. Numerical approximation using taylor series. Implementation loosely based on http://www.netlib.org/specfun/erf

Parameters:

x - parameter value

Returns:

erfc(x)

erf

public static final double erf(double x)

Error function for Gaussian distributions = Normal distributions. Numerical approximation using taylor series. Implementation loosely based on http://www.netlib.org/specfun/erf

Parameters:

x - parameter value

Returns:

erf(x)