Module rgsl::psi

The polygamma functions of order n are defined by

\psi^{(n)}(x) = (d/dx)ⁿ \psi(x) = (d/dx)^{n+1} \log(\Gamma(x))

where \psi(x) = \Gamma'(x)/\Gamma(x) is known as the digamma function.

Modules

diagamma
polygamma
trigamma