The Trigamma Function
Usage
trigamma(z)
Arguments
z
Vector argument. May be real or complex but must have positive real part.
Description
Calculates the trigamma function, which is the second derivative of the logarithm of the gamma function, for complex vector arguments.
Details
Uses an asymptotic expansion where Re(z) > 5 and a recurrence formula to such a case where Re(z) <= 5. Accuracy is good.
Value
Vector of trigamma(z) values.
References
M. Abramowitz and I. A. Stegun (1965)
Handbook of Mathematical Functions.
Dover.
See Also
digamma
[Package Contents]