SuanShu, a Java numerical and statistical library

com.numericalmethod.suanshu.analysis.function.special.gamma

Class Trigamma

• 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.
• "B. E. Schneider, "Algorithm 121: Trigamma Function," JSTOR. Vol. 27, No. 1, 1978."
• Wikipedia: Trigamma function
• "http://www.math.mcmaster.ca/peter/s743/trigamma.html"
• "http://lib.stat.cmu.edu/apstat/121"

• Nested classes/interfaces inherited from interface com.numericalmethod.suanshu.analysis.function.Function

Function.EvaluationException
• Constructor Summary

Constructors
Constructor and Description
Trigamma()
• Method Summary

All Methods
Modifier and Type Method and Description
double evaluate(double x)
Evaluate y = f(x).
• Methods inherited from class com.numericalmethod.suanshu.analysis.function.rn2r1.univariate.AbstractUnivariateRealFunction

evaluate
• Methods inherited from class com.numericalmethod.suanshu.analysis.function.rn2r1.AbstractRealScalarFunction

dimensionOfDomain, dimensionOfRange
• Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
• Methods inherited from interface com.numericalmethod.suanshu.analysis.function.Function

dimensionOfDomain, dimensionOfRange
• Constructor Detail

• Trigamma

public Trigamma()
• Method Detail

• evaluate

public double evaluate(double x)
Description copied from interface: UnivariateRealFunction
Evaluate y = f(x).
Parameters:
x - x
Returns:
f(x)