LogGamma (Apache Commons Numbers Gamma 1.2 API)

java.lang.Object
- org.apache.commons.numbers.gamma.LogGamma

```
public final class LogGamma
extends Object
```
Natural logarithm of the absolute value of \( \Gamma(x) \).
\[ \operatorname{lgamma}(z) = \ln \lvert \Gamma(x) \rvert \]
This code has been adapted from the Boost c++ implementation <boost/math/special_functions/gamma.hpp>.

See Also:

Boost C++ Log Gamma functions

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static double`	`value(double x)`	Computes the function \( \ln \lvert \Gamma(x) \rvert \), the natural logarithm of the absolute value of \( \Gamma(x) \).
`static double`	`value(double x, int[] sign)`	Computes the function \( \ln \lvert \Gamma(x) \rvert \), the natural logarithm of the absolute value of \( \Gamma(x) \).

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - value
```
public static double value(double x)
```
    Computes the function \( \ln \lvert \Gamma(x) \rvert \), the natural logarithm of the absolute value of \( \Gamma(x) \).
    
    Parameters:
    
    x - Argument.
    
    Returns:
    
    \( \ln \lvert \Gamma(x) \rvert \), or NaN if x <= 0 and is an integer.
  - value
```
public static double value(double x,
                           int[] sign)
```
    Computes the function \( \ln \lvert \Gamma(x) \rvert \), the natural logarithm of the absolute value of \( \Gamma(x) \).
    The sign output is set to 1 if the sign of gamma(x) is positive or zero; otherwise it is set to -1.
    
    Parameters:
    
    x - Argument.
    
    sign - Sign output. If a non-zero length the first index sign[0] is set on output to the sign of gamma(z).
    
    Returns:
    
    \( \ln \lvert \Gamma(x) \rvert \), or NaN if x <= 0 and is an integer.
    
    Since:
    
    1.1