Package org.apache.commons.numbers.gamma
Class LogGamma
java.lang.Object
org.apache.commons.numbers.gamma.LogGamma
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:
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic 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 \( \Gamma(x) \).
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Constructor Details
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LogGamma
private LogGamma()Private constructor.
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Method Details
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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
ifx <= 0
and is an integer.
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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 indexsign[0]
is set on output to the sign of gamma(z).- Returns:
- \( \ln \lvert \Gamma(x) \rvert \), or
NaN
ifx <= 0
and is an integer. - Since:
- 1.1
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