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


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