trigamma {MASS} | R Documentation |
Calculates the trigamma function, which is the second derivative of the logarithm of the gamma function, for complex vector arguments.
trigamma(z)
z |
Vector argument. May be real or complex but must have positive real part. |
Uses an asymptotic expansion where Re(z) > 5 and a recurrence formula to such a case where Re(z) <= 5. Accuracy is good.
Vector of trigamma(z) values.
M. Abramowitz and I. A. Stegun (1965) Handbook of Mathematical Functions. Dover.