Class Trigamma
- java.lang.Object
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- dev.nm.analysis.function.rn2r1.AbstractRealScalarFunction
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- dev.nm.analysis.function.rn2r1.univariate.AbstractUnivariateRealFunction
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- dev.nm.analysis.function.special.gamma.Trigamma
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- All Implemented Interfaces:
Function<Vector,Double>
,RealScalarFunction
,UnivariateRealFunction
public class Trigamma extends AbstractUnivariateRealFunction
The trigamma function is defined as the logarithmic derivative of the digamma function. That is, \[ \psi_1(z) = \frac{d}{dz} \psi(z) \] This implementation is based on Algorithm 121.- See Also:
- "B. E. Schneider, "Algorithm 121: Trigamma Function," JSTOR. Vol. 27, No. 1, 1978."
- Wikipedia: Trigamma function
- "http://pmtksupport.googlecode.com/svn/trunk/lightspeed2.3/trigamma.m"
- "http://www.math.mcmaster.ca/peter/s743/trigamma.html"
- "http://lib.stat.cmu.edu/apstat/121"
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Nested Class Summary
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Nested classes/interfaces inherited from interface dev.nm.analysis.function.Function
Function.EvaluationException
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Constructor Summary
Constructors Constructor Description Trigamma()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description double
evaluate(double x)
Evaluate y = f(x).-
Methods inherited from class dev.nm.analysis.function.rn2r1.univariate.AbstractUnivariateRealFunction
evaluate
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Methods inherited from class dev.nm.analysis.function.rn2r1.AbstractRealScalarFunction
dimensionOfDomain, dimensionOfRange
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface dev.nm.analysis.function.Function
dimensionOfDomain, dimensionOfRange
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Method Detail
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evaluate
public double evaluate(double x)
Description copied from interface:UnivariateRealFunction
Evaluate y = f(x).- Parameters:
x
- x- Returns:
- f(x)
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