Package org.apache.commons.numbers.gamma
Class Trigamma
java.lang.Object
org.apache.commons.numbers.gamma.Trigamma
Trigamma function.
It is the derivative of the
digamma function
:
\( \psi_1(x) = \frac{d^2}{dx^2} (\ln \Gamma(x)) \).-
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
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Field Details
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C_LIMIT
private static final double C_LIMITC limit.- See Also:
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S_LIMIT
private static final double S_LIMITS limit.- See Also:
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F_1_6
private static final double F_1_6Fraction.- See Also:
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F_1_30
private static final double F_1_30Fraction.- See Also:
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F_1_42
private static final double F_1_42Fraction.- See Also:
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Constructor Details
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Trigamma
private Trigamma()Private constructor.
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Method Details
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value
public static double value(double x) Computes the trigamma function.- Parameters:
x
- Argument.- Returns:
- trigamma(x) to within
1e-8
relative or absolute error whichever is larger.
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