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

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

`public final class ErrorFunctionsextends 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)

 Release 0.2 (2009-07-06_1820)